Susol руководство по эксплуатации

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Manuals and User Guides for LS Industrial Systems Susol Series. We have 1 LS Industrial Systems Susol Series manual available for free PDF download: Technical Catalogue

Страница 38 из 39

Переноска, хранение и монтаж
Переноска

Во избежание падения аппарата, установленного на монтажную рейку, не переносите его в перевернутом состоянии.
Не переносите аппарат, перевязав его тросом или проводом.
Не роняйте аппарат.

Хранение

Не храните аппарат в атмосфере, содержащей коррозионные газы.
Храните аппарат в положении ОТКЛ. или «Сработал».
Храните аппарат при относительной влажности воздуха не более 85 %.

Монтаж

Не допускайте попадания на аппарат капель дождя и масла, а также пыли, порошков и т.д.
Не закрывайте посторонними предметами верхние выводы аппарата.
Не допускайте попадания на аппарат прямого солнечного света.
Не снимайте изоляционную платину сзади аппарата.

Затягивая болтовые соединения проводников сзади, не погните контакты.
Расположите проводники параллельно и прочно прикрепите к выводам.
Удалите смазку.

Указания по эксплуатации
Susol

Условия эксплуатации
Автоматические выключатели Susol TD и TS могут эксплуатироваться при температуре от -25°С до +70″С. При температуре выше 40 С следует учитывать влияние температуры на рабочие характеристики аппарата. На высоте до 2000 м эксплуатационные характеристики аппарата не изменяются. Во избежание возгорания или выхода их строя не устанавливайте автоматические выключатели в местах, где они могут подвергаться ударному воздействию и сильным вибрациям, а также влиянию высокой температуры и влажности, коррозионных газов, пыли и т.д.
Рабочая температура окружающей среды: от -5С до 40С
Допустимая температура хранения: от -40С до 85С
Относительная влажность воздуха: 45~85%

Высота над уровнем моря: до 2000 м
Автоматические включатели с теплоэлектромагнитными расцепителями
При температуре выше 40С следует учитывать влияние температуры на рабочие характеристики аппарата. По дополнительному заказу автоматические выключатели Susol TD и TS выпускаются в исполнении с контрольной температурой 55 С.
Автоматические включатели с электронными расцепителями


Автоматические выключатели Susol TS с электронными расцепителями могут эксплуатироваться при температуре от -20 С до +70 С. При температуре выше 40Сследует учитывать влияние температуры на рабочие характеристики аппарата.
Автоматические выключатели Susol TD и TS с теплоэлектромагнитными расцепителями обеспечивают включение и отключение электропитания, и защиту от короткого замыкания при температурах не ниже — 25С. Допустимая температура хранения в оригинальной упаковке: от -40С до +85С.
В запыленной или влажной атмосфере выключатели следует устанавливать в пыле- и влагозащищенных оболочках.
Избегайте сильных вибраций, способных вызвать срабатывание аппарата или поломку его соединений и механических деталей.

В атмосфере, содержащей коррозионные газы, автоматические выключатели следует устанавливать в коррозионно-стойкой оболочке, защищающей от воздействия агрессивной среды.

Low voltage circuit breakersSuper SolutionNorth American
Edition

Low voltage circuit breakers

Susol LV circuit breakers

Super Solution

Overview Main characteristics Accessories Technical information
Mounting & connection Characteristics curves

A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-9

Contents

Dimensions Catalogue numbers Catalogue numbers index

Recognized Susol DesignSusol product represents simultaneously
simple and complicated design for using cut diamond motive to
emphasis on the hardness of industrial product. And we applied the
identity of product image by designing same concept MCCB and
Contactor which are installed to cubicle. Susol Series acquire the
competitive power By obtaining the prestigious IF Design Award

>>>

Super Solution

For power distribution High breaking capacity Optimum
coordination technique (Cascading & discrimination) Powerful
engineering tools

For protection of motor & its control device Optimal
overload protection Guaranteed Short Circuit Current Ratings

For controlling and disconnecting circuits For extensive
applications Wide range of optimized auxiliaries and
accessories

Global Leading Products

Circuit breakersFor protection of power distribution

Molded Case SwitchFor protecting and disconnecting circuits

MCCB

Beyond the limits…

The circuit breaker will supply more stable, reliable, upgraded
systems to customer with high breaking capacity.

Susol TD and TS series

Molded Case Circuit Breakers

Susol MCCBSimplified product rangeAF: 125AF, 250AF, 400AF, 800AF
Ampere Range: 15A ~ 800A

Standards

Various trip units

High performanceUltimate breaking capacity (kA rms) Icu: Max
65kA @480VAC

World class with UL489, CE approvals FTU: Fixed thermal &
Magnetic unit ATU: Adjustable thermal & Magnetic unit Variable
accessories FMU: Adjustable thermal, Fixed magnetic unit MCS:
Molded Case Switch Electrical auxiliaries Extended rotary handle
Flange handle Locking devices

MCCB8 Models in 4 FramesSusol TD and TS circuit breakers are
rated from 15 through 800 amperes and are available in four frame
sizes.

UL 489 Listed Circuit Breakers Family TD/ TS65kA at 480VAC / 8
models in 4 frames

TD125UIn 15~125A Icu: 35kA(NU), 65kA(HU) 90(W) x 164(H) x
86mm(D)

Enhanced high performanceN Type — 35kA, H Type — 65kAMaximum
breaking capacity for all Ampere Frame is 65kA at 480VAC.65kA 35kA
TS400HU TS800HU

TS800NU

TS400NU

TS250HU

TS250NU

TD125HU

TD125NU

800A 400A 250A 125A

65kA

35kA

High available fault current at 480V (kA)

TS800U TS400U TS250UIn 150~250A Icu: 35kA(NU), 65kA(HU) 105(W) x
178(H) x 86mm(D) In 300~400A Icu: 35kA(NU), 65kA(HU) 140(W) x
292(H) x 110mm(D) In 500~800A Icu: 35kA(NU), 65kA(HU) 210(W) x
428(H) x 135mm(D)

Rated current (A)

MCCB AccessoriesA complete range of convenient internal and
external accessories for Susol TD and TS series

Simplicity & FlexibilityVarious kinds of accessories for
user convenienceInternal auxiliaries (AX, AL, SHT, UVT) are the
same for all frame size. And trip units, Handles, Locking devices
are the same for a given frame size.

Alarm Switch (AL)

Auxiliary Switch (AX)

Shunt Trip (SHT)

Undervoltage trip (UVT)

Susol Circuit Breaker System Overview

Circuit breaker Flange handle (Cable operating handle) Extended
rotary handle Locking devices (Removable, Fixed) Mechanical
interlock device Accessories device (AL, AX, UVT, SHT) Trip
units

MCCB

Trip units

Interchangeable trip unit

*

Susol TS series circuit breakers provide several kinds of
protection function according to selected trip unit and thanks to
interchangeable trip unit concept, user can change the trip unit
easily and rapidly.* Only available in factory

Interchangeable trip units

Protection of power distribution systems1. Thermal Magnetic trip
units — FTU: Fixed thermal and Fixed magnetic trip unit — FMU:
Adjustable thermal and Fixed magnetic trip unit — ATU: Adjustable
thermal and Adjustable magnetic trip unitTS250 FTU

Im=2500AIr Im

250A40 3P

Motor Protection- MTU: Magnetic only trip unitTS250MTU1848 1584
1320Im

2112 2376 2640

220A3P

Thermal Magnetic Trip Unit — FTU

Thermal Magnetic Trip Unit — FMU

Thermal Magnetic Trip Unit — ATU

Control and disconnection- MCS: Molded case switchTS250 DSU

3P

15

20

32 40

50

60

80 100 128 150 160 175 200 225 250 300 350 400 500 600 700 800
FTU

Thermal-magnetic (Interchangeable)

FMU ATU

Mold ed Case Sw itch (Interchangeable)

MCS

MCCB

Internal accessories

SimplicityThe range of internal accessories of TD & TS
series circuit breakers is characterized by common use regardless
of frame size and is allowing reduction of stocks.

Internal accessoriesCommon use to all Susol TD and TS circuit
breakersElectrical auxiliaries that are installed internally are
common from 15A to 800A.Alarm Switch (AL)Alarm switches offer
provisions for immediate audio or visual indication of a tripped
breaker due to overload, short-circuit, operation of shunt trip, or
undervoltage trip conditions, operation of push button. They are
particularly useful in automated plants where operators must be
signaled about changes in the electrical distribution system. This
switch features a closed contact when the circuit breaker is
tripped automatically. In other words, this switch does not
function when the breaker is operated manually. Its contact is open
when the circuit breaker is reset.

Auxiliary Switch (AX)Auxiliary switch is for applications
requiring remote ON and OFF indication. Each switch contains two
contacts having a common connection. One is open and the other
closed when the circuit breaker is open, and viceversa.

Undervoltage trip (UVT)The undervoltage trip automatically opens
a circuit breaker when voltage drops to a value ranging between 35%
to 70% of the line voltage. The operation is instantaneous, and the
circuit breaker cannot be reclosed until the voltage returns to 85%
of line voltage. Continuously energized, the undervoltage trip must
be operating be fore the circuit breaker can be closed.

Shunt Trip (SHT)The shunt trip opens the mechanism in response
to an externally applied voltage signal. LS shunt trips include
coil clearing contacts that automatically clear the signal circuit
when the mechanism has tripped.

MCCB

External accessories

ConvenienceWide range of external accessories provides
convenient solution for easy installation.

External accessories

Extended rotary handleThere are 3 types of length 12/16/24inch
UL50 type 1, 3(R), 12 and 4(X) option available

Flange handle (Cable operating handle)There are 4 types of
length 36/48/60/72inch at each AF UL50 type 1, 3(R), 12 and 4(X)
option available

Locking deviceFixed padlock Removable padlock Key lock device on
direct handle

Mechanical interlocking deviceInterlocks prevent connection to
both sources at the same time, even momentarily.

MCCB

Main characteristics

Susol series circuit breakers are suitable forProtection of
power distribution Controlling and disconnecting circuits

Optimum technical support for(Cascading, Discrimination, Type 2
coordination) * Selecting economical protection system Quarantee
safety of the installation Reducing the stress on components and
damage Guarantee service continuity* Certificate under process

TD & TS MCCB Index

A-1. OverviewRange of Susol products Overview of TD/TS family
Marking and configuration Overview of trip units Switching
mechanism Degree of protectionA-1-1 A-1-3 A-1-5 A-1-7 A-1-9
A-1-10

Range of Susol products

125AF

250AF

Susol TD circuit breakers

For power distribution TD125U Thermal magnetic trip unitFTU
(Fixed thermal, Fixed magnetic trip unit) FMU (Adjustable thermal,
Fixed magnetic trip unit)

Susol TS circuit breakers

For power distribution

TS250U Thermal magnetic trip unitFTU (Fixed thermal, Fixed
magnetic trip unit) FMU (Adjustable thermal, Fixed magnetic trip
unit) ATU (Adjustable thermal, Adjustable magnetic trip unit)

Susol switch-disconnectors

Molded Case Switch TS125U Molded case switch unitMCS (Molded
Case Switch)

TS250U

A-1-1

Range of Susol products

400AF

800AF

Susol TD circuit breakers

For power distribution

Susol TS circuit breakers

For power distribution TS400U Thermal magnetic trip unitFTU
(Fixed thermal, Fixed magnetic trip unit) FMU (Adjustable thermal,
Fixed magnetic trip unit) ATU (Adjustable thermal, Adjustable
magnetic trip unit)

TS800U

Susol switch-disconnectors

Molded Case Switch TS400U Molded case switch unitMCS (Molded
Case Switch)

TS800U

A-1-2

Overview of TD/TS family

TD series

TD125UFrame size Rated current In No. of Poles Rated operational
voltage, Ue AC UL interrupting rating AC 50/60Hz 240 V 480 V 600 V
Reference standard Trip unit (Thermal-Magnetic) Fixed-thermal,
Fixed-magnetic Adjustable-thermal, Fixed-magnetic
Adjustable-thermal, Adjustable-magnetic (3Pole) Molded Case Switch
Variable accessories AX AL SHT UVT Extended rotary handle Flange
handle Locking devices (Removable, Fixed) Mechanical interlock
device Mechanical life Electrical life @600V AC Weight 3-Pole Basic
dimension, WHD 3-Pole [operations] [operations] [lbs/kg] [inch/m]
4,000 4,000 2.65/1.2 3.546.463.39/0.901.640.86

[AF] [A]

125 15, 20, 30, 40, 50, 60, 80, 100, 125 2, 3

[V] [kA]NU 50 35 10

600 HU 100 65 14 UL 489

FTU FMU ATU MCS

A-1-3

Overview of TD/TS family

TS series

TS250U250 150, 160, 175, 200, 225, 250 2, 3 600 NU 50 35 10 UL
489 HU 100 65 14 NU 50 35 10

TS400U400 300, 350, 400 2, 3 600 HU 100 65 14 UL 489 NU 50 35
10

TS800U800 500, 600, 700, 800 2, 3 600 HU 100 65 14 UL 489

5,000 1,000 4.19/1.9 4.137.013.39/1.051.780.86

5,000 1,000 12.57/5.7 5.5111.504.33/1.402.921.10

3,000 500 29.98/13.6 8.2716.855.31/2.104.281.35

A-1-4

Marking and configuration

Rated frequency

Standard

Manufacturer

Utilization category

UL listed number Terminal Information

Symbol indicating suitability for isolation as defined by
UL489

A-1-5

Marking and configuration

Model (Rating and breaking capacity) TS: Series 250: Max. Ampere
rating NU: Normal (Standard) HU: High Standardized characteristics:
Ui: Rated insulation voltage Uimp: Impulse withstand voltage Ue:
Rated operational voltage Icu: Ultimate breaking capacity Ics:
Service breaking capacity

125AF NU TD125NU

250AF TS250NU

400AF TS400NU

800AF TS800NU

HU

TD125HU

TS250HU

TS400HU

TS800HU

NU

50kA

50kA

50kA

50kA

HU

100kA

100kA

100kA

100kA

Product: Molded Case Circuit Breaker

Upstream connections Fixing hole Certificate plate Indication of
closed (I/ON) position

Brand name

Operating handle

Indication of open (O/OFF) position Company logo «push to trip»
button Rating of trip unit Trip unit

Fixing hole Downstream connections

A-1-6

Overview of trip units

On TD100U to TS800U circuit breakers, the thermal-magnetic trip
units are interchangeable and may be rapidly fitted to the circuit
breakers.

It is therefore easy to change the protection of a given circuit
following a modification in an uninstallation.

Ampere ratingsMCCB frame type Rated current, In[A] Thermal
magnetic release Type of trip unit TD125U FTU 15, 20, 30, 40, 50,
60, 80, 100, 125 150, 175, 200, 225, 250 300, 350, 400 FMU 32, 40,
48, 64, 80, 100 128, 160, 200 ATU MCS 15, 20, 30, 40, 50, 60, 80,
100, 125 150, 160, 175, 200, 225, 250 300, 350, 400

TS250U

128, 160, 200

TS400U

240, 320

240, 320

TS800U

500, 600, 700, 800

400, 480, 640

400, 480, 640

500, 600, 700, 800

Types of trip unitsFTU FMU ATU MCS

Fixed thermal, Fixed magnetic Adjustable thermal, Fixed magnetic
Adjustable thermal, Adjustable magnetic Molded case switch

A-1-7

Overview of trip units

FTU

Fixed-thermal, fixed-magneticTS250 FTU

Electronic trip unitIr Im

Im=2500AThermal magnetic trip unit

FMU

Adjustable-thermal, fixed-magnetic

Trip unit identificationTS250U FMU

Trip unit function

MCCB frame type ATU Adjustable-thermal, adjustable-magneticTS250
ATU0.8 0.9 1Ir Im

7 6 5

8 9 10

MCSFTU FMU ATU

Molded case switchTS250 DSU

3P

A-1-8

Switching mechanismDouble contactor structure

OptimizeRepulsion force Shape of contactor Induce easily the arc
mobility to grid direction Rapidly redeploy the arc from moving
contactor Prevent contact tip from erosion Open speed & contact
force

ON position

Unvarying contact force regardless of over travel Open speed of
moving contact is rapid by optimized cam curve regardless of trip
signal Function of trip freeOptimized cam curve

Force

Unvarying contact

Fig. 3 ON position

Angle

OFF position Push to trip in OFF position* Reset pin moment <
Main spring moment

Stability of endurance

600.0

Stress Amplitude (MPa)

500.0 400.0 300.0 200.0 100.0 0.0 0.00E+00

Fig. 4 OFF position

4.00E+06

3.00E+06

1.20E+07

1.60E+07

2.00E+07

Life

TRIP position Enables tripping mechanically from outside, for
confirming the operation of the accessory switches and the manual
resetting functionFig. 5 TRIP position

A-1-9

Degree of protection

The table indicates the degrees of protection guaranteed by
Susol TD and TS circuitbreakers according to several type of
installation. Basically, the fixed parts are always preset with
IP20 degree of protection.

IP65 degree of protection can be obtained with the
circuit-breaker installed in a switchboard fitted with an extended
rotary handle operating mechanism transmitted on the compartment
door.

Type

Degree of protection

IP

NEMA type

Protection of persons against access to hazardo us parts
with:

Extended rotary handle

There are 3 types of length

IP40

1, 3R,12 4X

Wire

Flange handle (Cable operating handle)

There are 4 types of length

IP40

1, 3R,12 4X

Wire

A-1-10

TD & TS MCCB Index

A-2. Main characteristicsMCCBs for power distributionElectrical
characteristics Thermal magnetic trip unitsOverview FTU, FMU for
TD125U FTU, FMU for TS250U, ATU for TS250U FTU, FMU, ATU for TS400U
FTU, FMU, ATU for TS800U A-2-4 A-2-5 A-2-8 A-2-11 A-2-15 A-2-2

Molded case switch

A-2-17

MCCBs for power distribution

TD series

TD125UFrame size No. of Poles Maximum voltage ratings Switch
ampere ratings Magnetic override Short circuit withstand ratings
120V AC 240V AC 480V AC 600V AC Catalog number of wire connector
Dimensions Shipping weight [V AC] [A] [A] [AF] 125 3 600 125 1250
100kA 100kA 65kA 14kA LSCA1 Same as MCCB Same as MCCB

A-2-1

MCCBs for power distribution

TS series

TS250U250

TS400U400 3

TS800U800

600 250 2500 100kA 65kA 18kA LSCA2

600 400 4000 100kA 65kA 20kA LSCA4 Same as MCCB Same as MCCB

800 8000 100kA 65kA 25kA LSCA8

A-2-2

MCCBs for power distributionThermal magnetic trip units
OverviewSusol TD & TS series circuit breakers can be installed
with thermal magnetic trip units. And, there are two kinds of trip
units according to way of installation as follows. Built-in trip
units for TD series upto 160A Interchangeable trip units for TS
series upto 800A

FunctionProtection of power distribution Overload protection:
Thermal protection with a fixed or adjustable threshold
Short-circuit protection: Magnetic protection with a fixed or
adjustable pick-up Protection of the fourth pole 4P3T type (neutral
unprotected) 4P4T type 50% (neutral protection at 0.5In) 4P4T type
100% (neutral protection at 1In)

OperationTrip bar

ATU

Thermal magnetic types Time-Delay operation An overcurrent heats
and warps the bimetal to actuate the trip bar by the bimetal
characteristic. Instantaneous operation If the overcurrent is
excessive, the armature is attracted and the trip bar actuated by
electromagnetic force.

Bimetal

Armature

RatingsRatings(A) at 40 TD125U TS250U TS400U TS800U In 15 20 30
40 Thermal magnetic trip units(FTU/FMU/ATU) 50 60 TD125U to TS800U
80 100 125 150 160 175 200 225 250 300 350 400 500 600 700 800

Note) Rated current 700A is available for TS800UFTU.

A-2-3

MCCBs for power distributionThermal magnetic trip units
OverviewCharacteristicsFixed thermal, fixed magnetic trip units FTU
Fixed thermal 15A … 800A rated currents Fixed magnetic 400A …
8000A tripping currents Applicable to TD125U … TS800U framesTS250
FTU

Im=2500AIr Im

Adjustable thermal, fixed magnetic trip units FMU Adjustable
thermal 40A … 800A rated currents Adjustable : 0.8~1In Fixed
magnetic 400A … 8000A tripping currents Applicable to TD125U …
TS800U frames

Adjustable thermal, adjustable magnetic trip units ATU
Adjustable thermal 150A … 800A rated currents Adjustable :
0.8~1In Adjustable magnetic 500A … 8000A tripping currents
Adjustable : 5~10In Applicable to TS250U … TS800U frames

TS250 ATU0.8

0.9 1Ir Im

7 6 5

8 9 10

A-2-4

MCCBs for power distributionThermal magnetic trip units FTU, FMU
for TD125U

ConfigurationTrip unit identification

Ratings (A), In at 40C Number of pole Short circuit protection
(magnetic) Setting current, Im

Overload protection (thermal) Setting current, Ir

TD125U FTU — Fixed thermal & magnetic trip unit

TD125FTUIm=1250AIr Im

125A

TD125U FMUt

0.9 0.8 1

TD125U FMU — Adjustable thermal & fixed magnetic trip
unit0.9 1Ir Im

TD125FMU0.8

Im=1250A

125A0 Ir Im I

A-2-5

MCCBs for power distributionThermal magnetic trip units FTU, FMU
for TD125U

CharacteristicsThermal magnetic trip units(FTU/FMU) … TD125U
Rating(A) at 40 In TD125U 15 20 30 40 50 60 80 100 125

Overload protection(thermal) Current setting(A) Ir FTU FMU Fixed
Adjustable 0.8, 0.9, 1In (3 settings)

Short — circuit protection(magnetic) Current setting(A) Im FTU
FMU Fixed 400A Fixed 400A Fixed 10In Fixed 10In

Catalogue numbering systemTD125U FMUTrip unit function — FTU :
Fixed thermal & magnetic unit — FMU : Adjustable thermal, fixed
magnetic unit MCCB frame type — TD125U : TD125NU, TD125HU

A-2-6

MCCBs for power distributionThermal magnetic trip units FTU, FMU
for TD125U

Setting detailsThermal overload protectionTrip unit type Setting
Ir TD125U FTU TD125U FMU Fixed 0.8 0.9 1 15 15 20 20 30 30 Trip
unit rating, In (A) 40 40 32 36 40 50 50 40 45 50 60 60 48 54 60 80
80 64 72 80 100 100 80 90 100 125 125 100 112.5 125

Magnetic short-circuit protectionTrip unit type Setting current,
Ir TD125U FTU TD125U FMU 0.8In 0.9In 1.0In Setting current, Im
Fixed Fixed Fixed Fixed In10 In10 In10 In10 15 400 20 400 30 400 40
400 400 400 400 Trip unit rating, In (A) 50 500 500 500 500 60 600
600 600 600 80 800 800 800 800 100 1000 1000 1000 1000 125 1250
1250 1250 1250

A-2-7

MCCBs for power distributionThermal magnetic trip units FTU, FMU
for TS250U ATU for TS250UConfigurationTrip unit identification

Ratings (A), In at 40C Number of pole Short circuit protection
(magnetic) Setting current, Im

Overload protection (thermal) Setting current, Ir

TS250U FTU — Fixed thermal fixed magnetic trip unitTS250 FTU

TS250U FMU

Im=2500AIr Im

TS250U FMU — Adjustable thermal fixed magnetic trip unit

TS250U ATUt

Short circuit protection (magnetic)0.9 0.8 1

TS250U ATU — Adjustable thermal adjustable magnetic trip
unitTS250 ATU0.8 0.9 1Ir Im

Short circuit protection (magnetic)7 6 8 9 5 10

7 6 5

8 9 100 Ir Im

I

A-2-8

MCCBs for power distributionThermal magnetic trip units FTU, FMU
for TS250U ATU for TS250UCharacteristicsThermal magnetic trip
units(FTU/FMU) … TS250U Rating(A) at 40 In TS250U Overload
protection(thermal) Current setting(A) Ir FTU FMU ATU Fixed
Adjustable 0.8 toIn Adjustable 0.8 toIn 150 160 175 200 225 250

Short — circuit protection(magnetic) Current setting(A) Im FTU
FMU ATU Fixed 10In Fixed 10In Adjustable 5, 6, 7, 8, 9, 10In (6
settings)

Catalogue numbering systemTS250U FTUTrip unit function — FTU:
Fixed thermal, fixed magnetic unit MCCB frame type — TS250U:
TS250NU, TS250HU

TS250U

FMUTrip unit function — FMU: Adjustable thermal, fixed magnetic
unit MCCB frame type — TS250U: TS250NU, TS250HU

TS250U

ATUTrip unit function — ATU: Adjustable thermal, adjustable
magnetic unit MCCB frame type — TS250U: TS250NU, TS250HU

The trip unit ATU is available from 125A

A-2-9

MCCBs for power distributionThermal magnetic trip units FTU, FMU
for TS250U ATU for TS250USetting detailsThermal overload
protectionTrip unit type Setting Ir TS250U FTU TS250U FMU Fixed 0.8
0.9 1 TS250U ATU 0.8 0.9 1 150 150 160 128 144 160 128 144 160 175
175 200 200 160 180 200 160 180 200 Trip unit rating, In (A) 225
225 250 250 200 225 250 200 225 250

Magnetic short-circuit protectionTrip unit type Setting current,
Ir TS250U FTU TS250U FMU 0.8 In 0.9 In 1.0 In TS250U ATU Setting
current, Im Fixed Fixed Fixed Fixed In 10 In 10 In 10 In 10 In 5 In
0.8 In Adjustable In In In 6 7 8 9 150 1500 160 800 960 1120 1280
1440 1600 800 960 1120 1280 1440 1600 800 960 1120 1280 1440 1600
Trip unit rating, In (A) 175 1750 200 2000 2000 2000 2000 1000 1200
1400 1600 1800 2000 1000 1200 1400 1600 1800 2000 1000 1200 1400
1600 1800 2000 225 2250 250 2500 2500 2500 2500 1250 1500 1750 2000
2250 2500 1250 1500 1750 2000 2250 2500 1250 1500 1750 2000 2250
2500

In 10 In 5 In 0.9 In Adjustable In In In 6 7 8 9

In 10 In 5 In 1.0 In Adjustable In In In 6 7 8 9

In 10

A-2-10

MCCBs for power distributionThermal magnetic trip units FTU,
FMU, ATU for TS400U

ConfigurationTrip unit identification

Ratings (A), In at 40C Number of pole Short circuit protection
(magnetic) Setting current, Im

Overload protection (thermal) Setting current, Ir

TS400U FTU — Fixed thermal fixed magnetic trip unit

TS400U FMU

TS400 FTUIm=4000AIr Im

400A

t

0.9 0.8 1

TS400U FMU — Adjustable thermal fixed magnetic trip unit

0

Ir

Im

I

TS400FMU0.9 0.8 1 Ir Im

400AIm=4000A TS400U ATUt

0.9 0.8 1

TS400U ATU — Adjustable thermal adjustable magnetic trip
unit

7

8 9

TS400ATU0.9 0.8 1 Ir Im 6 5 7 8 9 100 Ir Im

6

400A

5

10

I

A-2-11

MCCBs for power distributionThermal magnetic trip units FTU,
FMU, ATU for TS400U

CharacteristicsThermal magnetic trip units(FTU/FMU/ATU) …
TS400U Rating(A) at 40 In TS400U Overload protection(thermal)
Current setting(A) Ir FTU FMU ATU In=Ir (Fixed) Adjustable 0.8,
0.9, 1In (3 settings) Adjustable 0.8, 0.9, 1In (3 settings) 300 350
400

Short — circuit protection(magnetic) Current setting(A) Im FTU
FMU ATU Fixed 10In Fixed 10In Adjustable 5, 6, 7, 8, 9,10In(6
settings)

Catalogue numbering systemTS400U ATUTrip unit function — FTU :
Fixed thermal & magnetic unit — FMU : Adjustable thermal &
fixed magnetic unit — ATU : Adjustable thermal & adjustable
magnetic unit MCCB frame type — TS400U : TS400NU, TS400HU

A-2-12

MCCBs for power distributionThermal magnetic trip units FTU,
FMU, ATU for TS400U

Setting detailsThermal overload protectionTrip unit type Setting
Ir TS400U FTU TS400U FMU Fixed 0.8 0.9 1 TS400U ATU 0.8 0.9 1 300
300 240 270 300 240 270 300 Trip unit rating, In (A) 350 350 400
400 320 360 400 320 360 400

Magnetic short-circuit protectionTrip unit type Setting current,
Ir TS400U FTU TS400U FMU 0.8 In 0.9 In 1.0 In TS400U ATU Setting
current, Im Fixed Fixed Fixed Fixed In 10 In In In 10 10 10 300
3000 3000 3000 3000 1500 1800 2100 2400 2700 3000 1500 1800 2100
2400 2700 3000 1500 1800 2100 2400 2700 3000 Trip unit rating, In
(A) 350 3500 400 4000 4000 4000 4000 2000 2400 2800 3200 3600 4000
2000 2400 2800 3200 3600 4000 2000 2400 2800 3200 3600 4000

In 5 In 0.8 In Adjustable In In In 6 7 8 9

In 10 In 5 In 0.9 In Adjustable In In In 6 7 8 9

In 10 In 5 In 1.0 In Adjustable In In In 6 7 8 9

In 10

A-2-13

MCCBs for power distributionThermal magnetic trip units FTU,
FMU, ATU for TS800U

ConfigurationTrip unit identification

Ratings (A), In at 40C Number of pole

Short circuit protection (magnetic) Setting current, Im

Overload protection (thermal) Setting current, Ir

TS800U FTU — Fixed thermal fixed magnetic trip unit

TS800FTUIm=8000AIr Im

TS800U FMU

800At

0.9 0.8 1

TS800U FMU — Adjustable thermal fixed magnetic trip unit

TS800FMU0.9 0.8 1 Ir Im

0

Ir

Im

I

Im=8000A

800ATS800U ATUt

0.9 0.8 1

TS800U ATU — Adjustable thermal adjustable magnetic trip unit7 8
9 5 10

TS800ATU0.9 0.8 1 Ir Im 6 5 7 8 9 100 Ir Im

6

800A

I

A-2-14

MCCBs for power distributionThermal magnetic trip units FTU,
FMU, ATU for TS800U

CharacteristicsThermal magnetic trip units(FTU/FMU/ATU) …
TS800U Rating(A) at 40 In TS800U Overload protection(thermal)
Current setting(A) Ir FTU FMU ATU Fixed Adjustable 0.8, 0.9,1In (3
settings) Adjustable 0.8, 0.9,1In (3 settings) 500 600 700 800

Short — circuit protection(magnetic) Current setting(A) Im FTU
FMU ATU Fixed 10In Fixed 10In Adjustable 5, 6, 7, 8, 9, 10In (6
settings)

Catalogue numbering systemTS800U ATUTrip unit function — FTU :
Fixed thermal & magnetic unit — FMU : Adjustable thermal &
fixed magnetic unit — ATU : Adjustable thermal & adjustable
magnetic unit MCCB frame type — TS800U : TS800NU, TS800HU

A-2-15

MCCBs for power distributionThermal magnetic trip units FTU,
FMU, ATU for TS800U

Setting detailsThermal overload protectionTrip unit type Setting
Ir TS800U FTU TS800U FMU Fixed 0.8 0.9 1 TS800U ATU 0.8 0.9 1 500
500 400 450 500 400 450 500 Trip unit rating, In (A) 600 600 480
540 600 480 540 600 700 700 800 800 640 720 800 640 720 800

Magnetic short-circuit protectionTrip unit type Setting current,
Ir TS800U FTU TS800U FMU 0.8 In 0.9 In 1.0 In TS800U ATU Setting
current, Im Fixed Fixed Fixed Fixed In 10 In 10 In 10 In 10 In 5 In
0.8 In Adjustable In In In In 6 7 8 9 10 500 5000 5000 5000 5000
2500 3000 3500 4000 4500 5000 2500 3000 3500 4000 4500 5000 2500
3000 3500 4000 4500 5000 Trip unit rating, In (A) 600 6000 6000
6000 6000 3000 3600 4200 4800 5400 6000 3000 3600 4200 4800 5400
6000 3000 3600 4200 4800 5400 6000 700 7000 800 8000 8000 8000 8000
2000 4800 5600 6400 7200 8000 2000 4800 5600 6400 7200 8000 2000
4800 5600 6400 7200 8000

In 5 In 0.9 In Adjustable In In In In 6 7 8 9 10

In 5 In 1.0 In Adjustable In In In In 6 7 8 9 10

A-2-16

Molded case switch

The Molded case switch are different from the circuit-breakers
in the absence of the conventional protection unit. They keep the
overall dimensions, connection systems and accessories unchanged
from the

corresponding circuit-breakers. Installation standards require
upstream protection. However, thanks to their high-set magnetic
release, TD125U … TS800U MCS are self protected.

TD series

TD125UFrame size Conventional thermal current, Ith No. of poles
Rated operational voltage, Ue Rated operational current, Ie Rated
impulse withstand voltage,Uimp Rated insulation voltage, Ui Rated
short-circuit making capacity, Icm Rated short-time withstand
current, Icw 1s 3s 20s Isolation behavior Trip unit (release)
Molded case switch Connection fixed front-connection
rear-connection plug-in front-connection rear-connection Mechanical
life Electrical life @415 V AC Basic dimensions, WHD (front
connection) Weight (front connection) Reference standard 2-pole
3-pole 2-pole 3-pole [operations] [operations] [mm] [mm] [kg] [kg]
MCS [kV] [V] [kA peak] [A rms] [A rms] [A rms] AC DC [V] [V] [AF]
[A] 125 125 2, 3 600

A-2-17

Molded case switch

TS series

TS250U250 250 2, 3 600

TS400U400 400 2, 3 600

TS800U800 800 2, 3 600

Trip unit identification

A-2-18

TD & TS MCCB Index

A-3. AccessoriesElectrical auxiliariesUndervoltage release, UVT
Shunt release, SHT Auxiliary switch (AX), Alarm switch (AL) and
Fault alarm switch (FAL) Possible configuration of electrical
auxiliariesA-3-1 A-3-2 A-3-3 A-3-4

Rotary handlesRotary handlesA-3-5

Locking devicesRemovable locking device Fixed locking
deviceA-3-7 A-3-8

InterlockMechanical interlocking deviceA-3-9

AccessoriesElectrical auxiliariesThe following devices are
installed into all TD & TS circuit breakers regardless of frame
size. And, the electrical auxiliaries can be easily installed in
the accessory compartment of the circuit breakers which is cassette
type.

Undervoltage release, UVTThe undervoltage release automatically
opens a circuit breaker when voltage drops to a value ranging
between 35% to 70% of the line voltage. The operation is
instantaneous, and after tripping, the circuit breaker cannot be
reclosed again until the voltage returns to 85% of line voltage.
Continuously energized, the undervoltage release must be operating
before the circuit breaker can be closed. The undervoltage release
can be easily installed in the left accessory compartment of the
Susol TD and TS circuit-breakers.

UVT

Range of tripping voltage: 0.35 ~ 0.7Vn MCCB making is possible
voltage: 0.85Vn (exceed) Frequency (only AC): 45Hz ~ 65Hz

Technical dataControl voltage (V) AC/DC 24V Power consumption
AC/DC 48V AC/DC 110~130V AC 200~240V/DC 250V AC 380~440V AC
440~480V Max.opening time (ms) Tightening torque of terminal screw
Transformer operating voltage (V) — Drop (Circuit breaker trips) —
Rise (Circuit breaker can be switched on) 0.7~1.35Vn ~0.85Vn 0.64
1.09 0.73 1.21 1.67 1.68 Consumption AC (VA) DC (W) 0.65 1.10 0.75
1.35 50 8.2kgfcm mA 27 23 5.8 5.4 3.8 3.5 TD125U, TS250U, TS400U,
TS800U Applicable MCCBs

8.2kgfcm

A-3-1

AccessoriesElectrical auxiliaries

Shunt release, SHTThe shunt release opens the mechanism in
response to an externally applied voltage signal. The releases
include coil clearing contacts that automatically clear the signal
circuit when the mechanism has tripped. Range of operational
voltage: 0.7 ~ 1.1Vn Frequency (only AC): 45Hz ~ 65Hz The shunt
release can be installed in the left accessory compartment of the
Susol TD & TS circuit-breakers.

SHT

Technical dataControl voltage (V) DC 12V Power consumption AC/DC
24V AC/DC 48V AC/DC 110~130V AC 220~240V/DC250V AC 380~500V
Max.opening time (ms) Tightening torque of terminal screw 0.58 1.22
1.36 1.80 1.15 Consumption AC (VA) DC (W) 0.36 0.58 1.23 1.37 1.88
50 8.2kgfcm mA 30 24 25 10.5 7.5 2.3 TD125U, TS250U, TS400U, TS800U
Applicable MCCBs

8.2kgfcm

Click

A-3-2

AccessoriesElectrical auxiliaries

Auxiliary switch (AX), Alarm switch (AL)Auxiliary switch (AX)
Auxiliary switch is for applications requiring remote ON and OFF
indication. Each switch contains two contacts having a Alarm switch
(AL) Alarm switches offer provisions for immediate audio or visual
indication of a tripped breaker due to overload, short circuit,
shunt trip, or undervoltage release conditions. They are
particularly useful in automated plants where operators must be
signaled about changes in the electrical distribution system.
common connection. One is open and the other closed when the
circuit breaker is open, and vice-versa.

AX

This switch features a closed contact when the circuit breaker
is tripped automatically. In other words, this switch does not
function when the breaker is operated manually. Its contact is open
when the circuit breaker is reset.

Contact operationMCCBAL

ONAXa1 AXc1 AXb1

OFFAXc1

TRIPAXa1 AXb1

Position of AX Position of AL

AXa1 AXc1 AXb1 AXc1

AXa1 AXb1

Technical dataConventional thermal current Ith Rated operational
current Ie with rated operational voltage Ue — Altemating current
50/60Hz AC 125V 250V 500V — Direct current DC 30V 125V 250V 5A
Voltage Resistance 5 3 4 0.4 0.2 Ie Inductance 3 2 3 0.4 0.2
TD125U, TS250U, TS400U, TS800U

A-3-3

AccessoriesElectrical auxiliaries

Possible configuration of electrical auxiliariesMaximum
possibilitiesPhase Accessory AX R (Left) AL SHT or UVT T (Right) AX
AL TD125U 1 1 2 TS250U 1 1 1 1 TS400U 3 1 1 TS800U 3 1 2

TD125U

TS250U

TS400U

TS800U

AL AX AX SHT/ UVT SHT/ UVT AX AL *FAL AX

AX AX AX AL

*FAL

AX AX AX

AL AL

SHT/ UVT *FAL

SHT/ UVT

A-3-4

AccessoriesRotary handles

Extended handlesThe rotary handle operating mechanism is
available in either the direct version or in the extended version
on the compartment door.

MCCB TD125U TS250U TS400UExtended rotary handles

Extended Handle EH1 EH2 EH3 EH4

TS800U

Flange HandleThe flange hanle is operated by cable and can be
applied on the compartment door. This device is designed to easily
installed and operated for its own flexibility And, also can be
selected various length (4 types) at each frames.

MCCB TD125U TS250U TS400UFlange handle (Cable operating
handle)

Flange Handle FH1 FH2 FH3 FH4

TS800U

A-3-5

AccessoriesLocking devices

Removable locking deviceRemovable locking device is available
for all TD & TS circuit breakers. The locking device is
designed to be easily attached to the circuit-breaker. This device
allows the handle to be locked in the OFF position. Locking in the
OFF position guarantee isolation according to UL489 File E223241.
Removable locking deviceMCCB TD125U TS250U TS400U TS800U
Padlockable device PL1 PL2 PL3 PL4 OFF position Function

The locking device for the toggle handle can be installed in
2-pole and 3-pole circuit-breakers. Maximum three (3) padlocks with
shackle diameters ranging from 0.2~0.3inch(5~8mm) may be used.
(Padlocks are not supplied)

Cover Aux.

Pad-lock

0.2~0.3inch (5~8mm)

1.2inch (30mm)

Padlock dimensions

A-3-6

AccessoriesLocking devices

Fixed locking deviceFixed locking device is available for all TD
& TS circuit breakers. This device allows the handle to be
locked in the ON and OFF position. Locking in the OFF position
guarantee isolation according to IEC 60947-2. The locking device
for the toggle handle can be installed in 2-pole and 3-pole
circuit-breakers. Maximum three (3) padlocks with shackle diameters
ranging from 0.2~0.3inch(5~8mm) may be used. (Padlocks are not
supplied)

Fixed locking deviceMCCB TD125U TS250U TS400U TS800U Padlockable
device PHL1 PHL2 PHL3 PHL4 Lock in Off or On position Function

0.2~0.3inch (5~8mm)

How to useThe locking device for the toggle handle is designed
to be easily attached to the front of circuit-breaker. Please set
the toggle handle in the position of On or Off. Install the lock
device onto the front of auxiliary cover of circuit breaker.
Folding the wings of lock device as shown in picture 3. The padlock
to be used shall be that which is commercially available with the
nominal dimension. (1.2inch (30mm), nominal dimension, 0.2~0.3inch
(5~8mm) diameter)

1.2inch (30mm)

Padlock dimensions

TD125U

TS250U ~ TS800U

A-3-7

AccessoriesInterlock

Mechanical interlocking deviceThe mechanical interlock (MIT) can
be applied on the front of two breakers mounted side by side, in
either the 3-pole version and prevents simultaneous closing of the
two breakers. Fixing is carried out directly on the cover of the
breakers.Mechanical Interlock (Padlocks are not supplied)

The front interlocking plate allows installation of a padlock in
order to fix the position. (possibility of locking in the O-O
position as well) This mechanical interlocking device is very
useful and simple for consisting of manual source-changeover
system.

OperationFrame type TD125U

MCCB Pole 3-pole 4-pole TS250U 3-pole 4-pole

Interlock MIT13 MIT14 MIT23 MIT24 MIT33 MIT34 MIT43 MIT44

Left MCCB: ON/OFF is possible Right MCCB: Off lock

TS400U

3-pole 4-pole

TS800U

3-pole 4-pole

Interlock handle Interlock bar

Left MCCB: Off lock Right MCCB: ON/OFF is possible

Both MCCBs are of locked

A-3-8

TD & TS MCCB Index

A-4. Technical informationTemperature derating Power dissipation
/ Resistance ApplicationPrimary use of transformer Protection of
lighting & heating circuits Use of circuit-breakers for
capacitor banks Using circuit-breakers in DC networks Circuit
breakers for 400Hz networks Protection of several kinds of
loadsA-4-4 A-4-6 A-4-8 A-4-11 A-4-12 A-4-13 A-4-1 A-4-3

Protective coordinationDiscrimination & Cascading Cascading,
network 220/240V Cascading, network 380/415V Cascading, network
480/500V Protection discrimination table, Discrimination Type 2
Coordination according to IEC60947-4-1A-4-15 A-4-16 A-4-19 A-4-22
A-4-25 A-4-31

How to calculate short-circuit current valueVarious
short-circuit With percent impedance With a simple formula
Calculation example Combination of transformer and impedance
Various short-circuit Calculation example Calculation graphA-4-36
A-4-38 A-4-40 A-4-42 A-4-46 A-4-47 A-4-48 A-4-49

Technical informationTemperature derating

A derating of the rated operational current of the Susol TD and
TS molded case circuit breaker is necessary if the ambient
temperature is greater than 40C. Namely, when the ambient
temperature is greater than 40C, overload-protection
characteristics are

slightly modified. Electronic trip units are not affected by
variations in temperature. But, the maximum permissible current in
the circuit breaker depends on the ambient temperature.

Susol TD & TS series MCCB with thermal-magnetic trip
unitsMCCB Rating (A) 15 20 30 40 TD125U 50 60 80 100 125 150 160
175 TS250U 200 225 250 300 TS400U 350 400 500 TS800U 600 700 800
Fixed MCCB (c/w Thermal-magnetic trip unit) -12.2F 10C 15 20 30 40
50 60 80 100 125 150 160 175 200 225 250 300 350 400 500 600 700
800 -6.7F 20C 15 20 30 40 50 60 80 100 125 150 160 175 200 225 250
300 350 400 500 600 700 800 -1.1F 30C 15 20 30 40 50 60 80 100 125
150 160 175 200 225 250 300 350 400 500 600 700 800 4.4F 40C 15 20
30 40 50 60 80 100 125 150 160 175 200 225 250 300 350 400 500 600
700 800 10F 50C 15 19 29 39 48 58 78 97 121 145 155 170 194 219 242
291 341 388 484 580 680 775 15.6F 60C 14 19 28 38 47 56 75 94 117
140 150 165 188 213 234 281 331 375 469 571 661 750 21.1F 70C 13 18
26 35 44 53 71 88 110 131 141 156 176 201 220 264 314 353 441 525
625 705 26.7F 80C 12 16 24 33 41 49 66 82 103 121 131 146 164 189
205 246 296 328 410 487 587 656

Note) TD160 1pole MCCB is not applied to temperature
derating.

A-4-1

Technical informationPower dissipation / Resistance

Susol TD & TS series MCCB with thermal-magnetic trip unitsAF
Rating (A) Fixed MCCB R (m ) Watt single pole Watt three poles 15
5.60 1.43 4.30 20 5.60 2.24 6.72 30 3.80 3.89 11.67 TD125U (2P
& 3P) 40 1.84 2.94 50 1.34 3.35 60 1.10 4.37 13.10 80 0.91 5.82
17.47 100 0.70 7.00 21.00 125 0.61 9.53 28.59

8.83 10.05

AF Rating (A) Fixed MCCB R (m ) Watt single pole Watt three
poles 150 0.62 13.95 41.85 160 0.62 15.87 47.62

TS250U (2P & 3P) 175 0.52 15.93 47.78 200 0.52 20.80 62.40
225 0.25 12.66 37.97 250 0.25 15.79 47.38

AF Rating (A) Fixed MCCB R (m ) Watt single pole Watt three
poles 300 0.30 26.82 80.46

TS400U(2P & 3P) 350 0.30 36.75 110.25 400 0.30 47.68
143.04

AF Rating (A) Fixed MCCB R (m ) Watt single pole Watt three
poles 500 0.49 122.50 367.50

TS800U (2P & 3P) 600 0.49 176.40 529.20 700 0.12 58.80
176.40 800 0.12 76.80 230.40

Power dissipated per pole (P/pole): Watts (W). Resistance per
pole (R/pole): Milliohms (m) (measured cold). Total power
dissipation is the value measured at In, 50/60 Hz, for a 3 pole or
4 pole circuit breaker (Power= 3I2R)

A-4-2

Technical informationApplication Primary use of
transformerApplication for transformer protectionTransformer
excitation surge current may possibly exceed 10 times rated
current, with a danger of nuisance tripping of the MCCB. The
excitation surge current will vary depending upon the supply phase
angle at the time of switching, and also on the level of core
residual magnetism. So, its recommended to select proper circuit
breakers according to the continuous current carrying capacity of
transformer. It requires to consider separately whether transformer
is single phase or three phase. The below table indicates the
proper molded case circuit breaker suitable for each
transformer.

AC240VCapacity of 3 phase transformer (kVA) Capacity of single
phase transformer (kVA) Breaking capacity (kA) (sym) Frame (A) 125
250 400 800 Below 1500 Below 300 50 TD125NU TS250NU TS400NU TS800NU
TD125HU TS250HU TS400HU TS800HU 100 Below 1500 Below 2000 —

AC480VCapacity of 3 phase transformer (kVA) Breaking capacity
(kA) (sym) Frame (A) 125 250 400 800 TD125NU TS250NU TS400NU
TS800NU Below 2000 35 TD125HU TS250HU TS400HU TS800HU 65 Below
3000

A-4-3

Technical informationApplication Primary use of
transformerApplication for transformer protection (MCCBs for
Transformer-Primary Use)Transformers are used to change in the
supply voltage, for both medium and low voltage supplies. The
choice of the protection devices should be considered transient
insertion phenomena, during which the current may reach values
higher than the rated full load current; the phenomenon decays in a
few seconds. The peak value of the first half cycle may reach
values of 15 to 25 times the effective rated current. For a
protective device capable of protecting these units this must be
taken into account. Manufacturers data and tests have indicated
that a protective device feeding a transformer must be capable of
carrying the following current values without tripping.

TD125U, TS250U~800U equipped with Thermal magnetic trip units1
phase 240V 3 to 4 4 to 5 5 to 7 7 to 9 9 to 12 12 to 14 14 to 19 19
to 24 24 to 30 30 to 36 36 to 42 42 to 48 48 to 54 54 to 60 60 to
72 72 to 84 84 to 96 96 to 120 120 to 144 144 to 168 168 to 192
Transformer ratings (kVA) 3 phase 240V 1 phase 415V 5 to 6 6 to 8 9
to 12 13 to 16 16 to 20 20 to 24 24 to 32 32 to 41 41 to 51 51 to
62 62 to 72 72 to 83 83 to 93 93 to 103 103 to 124 124 to 145 145
to 166 166 to 207 207 to 249 249 to 290 290 to 332 3 phase 415V 8
to 10 10 to 14 14 to 21 21 to 28 28 to 35 35 to 43 43 to 57 57 to
71 71 to 89 89 to 107 107 to 125 125 to 143 143 to 161 161 to 179
179 to 215 215 to 251 251 to 287 287 to 359 359 to 431 431 to 503
503 to 575 MCCB rated current (A) 15 20 30 40 50 60 80 100 125 150
175 200 225 250 300 350 400 500 600 700 800 FTU FMU ATU Trip
unit

A-4-4

Technical informationApplication Protection of lighting &
heating circuitsIn the lighting & heating circuits,
switchingsurge magnitudes and times are normally not sufficient to
cause serious tripping problems. But, in some cases, such as
incandescent lamps, mercury arc lamps, metal halide and sodium
vapour, or other large starting-current equipment, the proper
selection should be considered. Upon supply of a lighting
installation, for a brief period an initial current exceeding the
rated current (corresponding to the power of the lamps) circulates
on the network. This possible peak has a value of approximately
1520 times the rated current, and is present for a few
milliseconds; there may also be an inrush current with a value of
approximately 1.53 times the rated current, lasting up to some
minutes. The correct dimensioning of the switching and protection
devices must take these problems into account. Generally, it is
recommended to make the maximum operating current not to exceed 80%
of the related current.

AC220VThe maximum operating current (A) 12 16 24 32 40 48 64 80
100 120 140 160 180 200 240 280 320 400 480 560 640 The rated
Breaking capacity (kA) current of sym MCCB (A) 15 20 30 40 50 60 80
100 125 150 175 200 225 250 300 350 400 500 600 700 800 TS800NU
TS800HU TS400NU TS400HU TS250NU TS250HU TD125NU TD125HU 50 100

A-4-5

Technical informationApplication Protection of lighting &
heating circuitsAC480VThe maximum operating current (A) 12 16 24 32
40 48 64 80 100 120 140 160 180 200 240 280 320 400 480 560 640 The
rated Breaking capacity (kA) current of sym MCCB (A) 15 20 30 40 50
60 80 100 125 150 175 200 225 250 300 350 400 500 600 700 800
TS800NU TS800HU TS400NU TS400HU TS250NU TS250HU TD125NU TD125HU 35
65

A-4-6

Technical informationApplication Protection of resistance
welding circuitsShort circuit protection for resistance welding
devices can be obtained by applying molded case circuit breaker
properly. These breakers permit normally high welding currents, but
trip instantaneously if a short circuit develops. It’s recommended
to select proper circuit breaker according to the characteristics
of welding devices as the follow table.

Characteristics of welding device Capacity (kVA) Maximum input
(kVA)

Applied circuit breaker (MCCB 2P) 240V (Single phase) 415V
(Single phase)

15

35

TD125NU/HU 125A

TD125NU/HU 50A

30

65

TS250NU/HU 150A

TD125NU/HU 125A

55

140

TS250NU/HU 250A

TD125NU/HU 125A

A-4-7

Technical informationApplication Use of circuit-breakers for
capacitor banksApplication for protection of capacitor circuitC

Capacitor circuit

In order to reduce system losses (less than 0.5W/kvar in low
voltage) and voltage drops in the power distribution system,
reactive power compensation or power factor correction is generally
undertaken. As a result, the power fed into the system is used as
active power and costs will be saved through a reduction in
Examples of equipment which consume reactive energy are all those
receivers which require magnetic fields or arcs in order to
operate, such as: — Asynchronous motors: An asynchronous motor is a
large consumer of inductive reactive energy. The amount of reactive
power consumed is between 20% and 25% of the rated power of the
motor (depending on its speed). — Power Transformers: Power
transformers are normally always connected. This means that
reactive energy is always consumed. Also, as a consequence of its
inductive nature, the reactive energy increases when the
transformer is loaded. — Discharge lamps, Resistance-type soldering
machines, Dielectric type heating ovens, Induction heating ovens,
Welding equipments, Arc furnaces

the capacitive and inductive power factors. The compensation can
be carried out by the fixed capacitors and automatic capacitor
banks. However, the disadvantages of installing capacitors are
sensitivity to over-voltages and to the presence of nonlinear
loads.

L1 L2 L3 1 2 3 4 5 6 Breaker

1 2

3 4

5 Contactor 6

O/L

At the instant of closing a switch to energize a capacitor, the
current is limited only by the impedance of the network upstream of
the capacitor, so that high peak values of current will occur for a
brief period, rapidly falling to normal operating values. According
to the relevant standards IEC 60831-1/IEC 70, capacitors must
function under normal operating conditions with the current having
a RMS value up to 1.3 times the rated current of the capacitor.
Additionally, a further tolerance of up to 15% of the real value of
the power must be taken into consideration. The maximum current
with which the selected circuit-breaker can be constantly loaded,
and which it must also be able to switch, is calculated as follows:
Maximum expected rated current = Rated current of the capacitor
bank1.5 (RMS value)

T1

T2 T3 C M Motor

L1 L2 L3 1 2 3 4 5 6 Breaker

1 2

3 4

5 Contactor 6 O/L

T1

T2 T3 C M Motor

L1 L2 L3 1 2 3 4 5 6 Breaker 1 2 3 4 5 6 Breaker

1 2

3 4

5 Contactor 6 O/L C

T1

T2 M

T3

Motor

Usual connection diagram

A-4-8

Technical informationApplication Using circuit-breakers in DC
networksSusol circuit-breakers for protection of power distribution
with thermal overload and magnetic short-circuit trip units are
suitable for usage in Circuit-breaker selection criteria The
followings are the most important criteria for selection of
suitable circuit breaker for DC networks. The rated current
determines the rating and size of the circuit-breaker (Equipment)
Setting range of the trip values Thermal overload protection: Same
setpoints as in 50/60Hz circuits DC networks. The circuit-breakers
with electronic overcurrent releases are not suitable for DC
networks. The rated voltage determines the number of poles in
series necessary for breaking The maximum short-circuit current at
the connection point determines the breaking capacity Instantaneous
short-circuit protection: The response threshold increases by
maximum 40%.

The following wiring diagrams are recommended since the current
must flow through all current paths in order to conform to the
thermal tripping characteristic curve.-(N) +(P) -(N) +(P)

Load

Load

Recommended wiring method for DC500V circuit

Recommended wiring method for DC600V circuit

Model TD125NU TS250NU TS400NU Thermal magnetic TS800NU TD125HU
TS250HU TS400HU TS800HU

Trip unit

Applicable to DC circuits

Breaking capacity (kA) 42

FTU FMU ATU

50

65

85

A-4-9

Technical informationApplication Circuit breakers for 400Hz
networksWhen circuit breakers are used at high frequencies, the
breakers in many cases require to be derated as the increased
resistance of the copper sections resulting from the skin effect
produced by eddy currents at 400Hz. Standard production breakers
can be used with alternating currents with frequencies other than
50/60 Hz (the frequencies to which the rated performance of the
device refer, with alternating current) as appropriate derating
coefficients are applied.

Thermal magnetic trip unitsThermal trip As can be seen from the
data shown in below, the tripping threshold of the thermal element
(ln) decreases as the frequency increases because of the reduced
conductivity of the Instantaneous trip The magnetic threshold
increases with the increase in frequency. materials and the
increase of the associated thermal phenomena. Rated current (A) at
400Hz= K1 rated current (A) at 50/60Hz

Instantaneous current (A) at 400Hz = K2Instantaneous current (A)
at 50/60Hz

Thermal magnetic trip unitsTD and TS series performance table at
400HzRated current (A) in 400 Hz 15 20 30 40 50 60 80 100 125 150
160 175 200 225 250 300 350 400 500 600 700 800Note) K1Multiplier
factor of rated current (In) K2-Multiplier factor of instantaneous
current due to the induced magnetic fields FTU-Fixed Thermal and
magnetic trip unit FMUAdjustable thermal and fixed magnetic trip
unit ATUAdjustable thermal and magnetic trip unit

Applied circuit breaker (MCCB)

Multiplier factors (K1, K2) Trip unit K1 (Thermal trip units)
0.8 0.8 0.8 0.8 K2 (Magnetic trip units) 2 2 2 2 2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2

TD125NU, TD125HU

0.8 0.8 0.8 FTU FMU ATU 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8

TS250NU, TS250HU

TS400NU, TS400HU

0.8 0.8 0.8 0.8 0.8 0.8

TS800NU, TS800HU

A-4-10

Technical informationApplication Protection of several kinds of
loadsApplication for protection of several kinds of loadsIt
requires to select proper circuit breakers according to the
characteristics of loads when they are installed to protect several
kinds of loads. It’s needed to consider the maximum operating
current and the capacity of loads in total so as to select the
rated current of breakers.

Selection of circuit breaker protecting the several loads
simultaneouslyThe kind of loads (IM: motors, IL: others) In case
of, IM ILIb Iw M IM1 M IM2 IL1 IL2

Permissible current in cable or wire: IW

The rated current of circuit breaker: Ib

IW IM + IL Choose the low value among two formulas: Ib 3IM + IL.
and Ib 2.5IW Iw 1.25IM + IL Its permitted to select the above value
only if IW (above 100A) isnt subject to the rated current of
circuit breaker. IW 1.1IM + IL

In case of, IM IL, IM 50AIb Iw

M IM1 M IM2 IL1 IL2

In case of, IM IL, Ib IM 50AIw

M IM1 M IM2 IL1 IL2

The rated current of breakers as the main circuit of 3 phase
inductive loads (AC 220V)Capacity of loads In total (below kW) 3
4.5 6.3 8.2 12 15.7 19.5 23.2 30 37.5 45 52.5 63.7 75 86.2 97.5
112.5 125 150 1751kw 1.3405hp Capacity of the highest motor (HP/ A)
The maximum operating current 1.00 2.01 2.95 4.96 7.37 10.0 14.7
20.1 24.8 29.4 40.2 49.6 60.3 73.7 100. 120. 5 0 5 5 0 0 9 1 0 2 3
53 64 (below A) 4.8 8 11.1 17.4 26 34 48 65 79 93 125 160 190 230
310 360

15 20 30 40 50 75 90 100 125 150 175 200 250 300 350 400 450 500
600 700

20 40 40 50 80 100 100 125 160 200 200 250 300 400 400 500 500
700 700 800

30 40 40 50 80 100 100 125 160 200 200 250 300 400 400 500 500
700 700 800

30 40 40 50 80 100 100 125 160 200 200 250 300 400 400 500 500
700 700 800

50 50 50 80 100 100 125 160 200 200 250 300 400 400 500 500 700
700 800

80 80 80 100 100 125 160 200 200 250 300 400 400 500 500 700 700
800

100 100 100 100 125 160 200 200 250 300 400 400 500 500 700 700
800

125 125 125 160 200 200 250 300 400 400 500 500 700 700 800

160 160 160 160 200 200 250 300 400 400 500 500 700 700 800

200 200 200 200 200 250 300 400 400 500 500 700 700 800

200 250 250 250 250 300 400 400 500 500 700 700 800

300 300 400 300 400 300 400 400 400 400 400 500 500 500 500 700
700 700 700 800 800

500 500 500 500 500 500 700 700 800

500 500 500 500 500 700 700 800

630 630 700 700 700 800

700 700 700 800 800

A-4-11

Technical informationApplication Protection of several kinds of
loadsThe rated current of breakers as the main circuit of 3 phase
inductive loads (AC 440V)Capacity of loads In total (below kW) 3
4.5 6.3 8.2 12 15.7 19.5 23.2 30 37.5 45 52.5 63.7 75 86.2 97.5
112.5 125 150 175 200 250 300 Capacity of the highest motor (HP/ A)
1kw 1.3405hp The maximum operating 1.00 2.95 10.0 14.7 20.1 24.8
29.4 40.2 49.6 60.3 73.7 100. 120. 147. current 5 2.01 0 4.96 7.37
5 5 0 0 9 1 0 2 3 53 64 45 (below A) 4.8 8 11.1 17.4 26 34 48 65 79
93 125 160 190 230 310 360 220 7.5 10 15 20 25 38 45 50 63 75 88
100 125 150 175 200 225 250 300 350 400 500 600 20 20 20 40 40 50
50 80 80 20 20 20 40 40 50 50 80 80 20 20 20 40 40 50 50 80 80 40
40 40 40 50 50 80 80 40 40 40 50 50 80 80 50 50 50 50 80 80 80 80
80 80 80 80 100 80 100 125 80 100 125

100 100 100 100 100 100 100 100 100 125 160 100 100 100 100 100
100 100 100 100 125 160 200 125 125 125 125 125 125 125 125 125 125
160 200 250 160 160 160 160 160 160 160 160 160 160 160 200 250 250
200 200 200 200 200 200 200 200 200 200 200 200 250 250 200 200 200
200 200 200 200 200 200 200 200 200 250 300 400 250 250 250 250 250
250 250 250 250 250 250 250 250 300 400 400 500 250 250 250 250 250
250 250 250 250 250 250 250 250 300 400 400 500 300 300 300 300 300
300 300 300 300 300 300 300 300 300 400 400 500 400 400 400 400 400
400 400 400 400 400 400 400 400 400 400 400 500 400 400 400 400 400
400 400 400 400 400 400 400 400 400 400 500 700 500 500 500 500 500
500 500 500 500 500 500 500 500 500 500 500 700 700 700 700 700 700
700 700 700 700 700 700 700 700 700 700 700 800 700 700 700 700 700
700 700 700 700 700 700 700 700 700 700 700 800

Notes) The above mentioned technical data is defined under the
usage conditions as follows ; 1. The circuit breaker is tripped
within 10seconds in 600% of the current of the fully operating
loads. 2. The start-up input current is set within 1700% of the
current of the fully operating loads. 3. The capacity of highest
motor is also applied when several loads starts up
simultaneously.

A-4-12

Technical informationProtective coordination Discrimination
& CascadingThe primary purpose of a circuit protection system
is to prevent damage to series connected equipment and to minimize
the area and duration of power loss. The first consideration is
whether an air circuit breaker or molded case circuit breaker is
the most suitable. The next is the type of system to be used. The
two major types are: Discrimination and cascading.

DiscriminationMain breaker Comtinuous supply

According to IEC60947-2, the discrimination Total discrimination
(total selectivity) Over-current discrimination where, in the
presence of two over-current protective devices in series, the
protective device on the Partial discrimination (partial
selectivity) Over-current discrimination where, in the presence of
two over-current protective devices in series, the protective
device on the No discrimination In case of a fault, main and branch
circuit

can be defined as follows. load side effects the protection
without causing the other protective device to operate.

Branch breaker

Healthy circuit

Short-circuit point

load side effects the protection up to a given level of
over-current, without causing the other protective device to
operate. breakers open.

Main breaker

Branch breaker

CascadingThis is an economical approach to the use of circuit
breakers, whereby only the main (upstream) breaker has adequate
interrupting capacity for the maximum available fault current. The
MCCBs downstream cannot handle this maximum fault current and rely
on the opening of the upstream breaker for protection. The
advantage of the cascade back-up approach is that it facilitates
the use of low cost, low fault level breakers downstream, thereby
offering savings in both the cost and size of equipment. As Susol
TD & TS circuit breakers have a very considerable current
limiting effect, they can be used to provide this cascade back-up
protection for downstream circuit breakers.

Fault point

A-4-13

Technical informationProtective coordination Cascading, network
240VComplementary technical informationMain: Susol UL TD Branch:
Susol UL TD, TSTD125NU 50 TD125HU 100 75 75 75 75 TS250NU 50
TS250HU 100 75 75 75 75 Main breaker Branch breaker Rated breaking
capacity (kArms) TD125NU TD125HU Susol TS250NU TD & TS TS250HU
TS400NU TS400HU TS800NU TS800HU 50 100 50 100 50 100 50 100

Main breaker Branch breaker Rated breaking capacity (kArms)
TD125NU TD125HU Susol TS250NU TD & TS TS250HU TS400NU TS400HU
TS800NU TS800HU 50 100 50 100 50 100 50 100

TS400NU 50 —

TS400HU 100 75 75 75 75 —

TS800NU 50 —

TS800HU 100 75

75 75 75 —

A-4-14

Technical informationProtective coordination Cascading, network
480VComplementary technical informationMain: Susol UL TD Branch:
Susol UL TD, TSTD125NU 35 TD125HU 65 50 50 50 50 TS250NU 35 TS250HU
65 50 50 50 50 Main breaker Branch breaker Rated breaking capacity
(kArms) TD125NU TD125HU Susol TS250NU TD & TS TS250HU TS400NU
TS400HU TS800NU TS800HU 35 65 35 65 35 65 35 65

Main breaker Branch breaker Rated breaking capacity (kArms)
TD125NU TD125HU Susol TS250NU TD & TS TS250HU TS400NU TS400HU
TS800NU TS800HU 35 65 35 65 35 65 35 65

TS400NU 35 —

TS400HU 65 50 50 50 50 —

TS800NU 35 —

TS800HU 65 50 50 50 50 —

A-4-15

Technical informationProtective coordination Cascading, network
600VComplementary technical informationMain: Susol UL TD Branch:
Susol UL TD, TSTD125NU 10 TD125HU 14 12 12 TS250NU 10 TS250HU 18 14
16 14 16 Main breaker Branch breaker Rated breaking capacity
(kArms) TD125NU TD125HU Susol TS250NU TD & TS TS250HU TS400NU
TS400HU TS800NU TS800HU 10 14 10 18 14 20 18 25

Main breaker Branch breaker Rated breaking capacity (kArms)
TD125NU TD125HU Susol TS250NU TD & TS TS250HU TS400NU TS400HU
TS800NU TS800HU 10 14 10 18 14 20 18 25

TS400NU 14 12 12 —

TS400HU 20 15 17 15 19 17 19 —

TS800NU 18 14 16 14 16 —

TS800HU 25 17 19 17 21 19 22 21 —

A-4-16

Technical informationProtective coordination Protection
discrimination table, DiscriminationComplementary technical
informationMain: TD125U (Thermal magnetic)Branch breaker Main
breaker Rating (A) 15 15 20 30 40 N 50 60 80 Susol TD & TS 100
Trip unitsThermal magnetic 125 15 20 30 40 H 50 60 80 100 125 150
160 N Susol TD & TS H 175 200 225 Trip unitsThermal magnetic
250 150 160 175 200 225 250 1.25kA 0.5kA 0.5kA 0.5kA 0.63kA 0.8kA
0.5kA 0.5kA 0.63kA 0.8kA 0.5kA 0.63kA 0.8kA 0.63kA 0.8kA 0.63kA
0.8kA 0.8kA 2kA 2kA 2kA 2kA 2kA 2kA T T 50kA 50kA 50kA 50kA 50kA
50kA 20 30 TD125NU/HU Trip units-Thermal magnetic 40 50 60 80 100
125 2kA 2kA 2kA 2kA 2kA 2kA 1.25kA 150 2kA 2kA 2kA 2kA 2kA 2kA 2kA
0.5kA 0.5kA 0.5kA 0.63kA 0.8kA 0.5kA 0.5kA 0.63kA 0.8kA 0.5kA
0.63kA 0.8kA 0.63kA 0.8kA 0.63kA 0.8kA 0.8kA

Branch: TD125U (Thermal magnetic)TS 250NU/ HU Trip units-Thermal
magnetic 160 2kA 2kA 2kA 2kA 2kA 2kA 2kA 175 T T T T T T T T 200 T
T T T T T T T 4kA T T 50kA 50kA 50kA 50kA 50kA 50kA 4kA 225 T T T T
T T T T 4kA T T 50kA 50kA 50kA 50kA 50kA 50kA 4kA

1.6kA 1.6kA

1.25kA 1.25kA T T 50kA 50kA 50kA 50kA 50kA 50KA T T 50kA 50kA
50kA 50kA 50kA 50kA

1.25kA 1.25kA 1.25kA

A-4-17

Technical informationProtective coordination SCCR according to
UL489

MCCB

MC Performance: Ue=240V MCCB TD125U NU 50kA HU 100kA TOR

Motor hp (kW) 0.49 (0.37) 0.737 (0.55) 1.005 (0.75) 1.474 (1.1)
2.01 (1.5) 2.95 (2.2) 4.02 (3) 4.959 (3.7) 5.36 (4) 7.37 (5.5)
10.05 (7.5) 12.06 (9) 13.41 (10) 14.745 (11) 20.11 (15) A 1.8 Type
TD125U

MCCB Rating Ir (A) 15

Contactor Type MC-9

Thermal overload relay Type MT-32 Setting range (A) 1.6-2.5

2.75

TD125U

15

MC-32

MT-32

2.5-4

3.5

TD125U

15

MC-32

MT-32

2.5-4

4.4

TD125U

15

MC-40

MT-63

4-6

6.1

TD125U

15

MC-40

MT-63

5-8

8.7

TD125U

15

MC-40

MT-63

9-13

11.5

TD125U

15

MC-40

MT-63

9-13

13.5

TD125U

15

MC-40

MT-63

12-18

14.5

TD125U

15

MC-40

MT-63

12-18

20

TD125U

20

MC-40

MT-63

16-22

27

TD125U

30

MC-40

MT-63

24-36

32

TD125U

40

MC-85

MT-95

28-40

35

TD125U

40

MC-85

MT-95

28-40

39

TD125U

40

MC-85

MT-95

34-50

52

TD125U

60

MC-85

MT-95

45-65

A-4-18

Technical informationProtective coordination SCCR according to
UL489

MCCB

MC Performance: Ue=480V MCCB TD125U NU 50kA HU 100kA TOR

Motor hp (kW) 0.49 (0.37) 0.737 (0.55) 1.005 (0.75) 1.474 (1.1)
2.01 (1.5) 2.95 (2.2) 4.02 (3) 4.959 (3.7) 5.36 (4) 7.37 (5.5)
10.05 (7.5) 12.06 (9) 13.41 (10) 14.745 (11) 20.11 (15) 24.80
(18.5) 29.49 (22) 33.51 (25) A 1.03 1.6 2 2.6 3.5 5 6.6 7.7 8.5
11.5 15.5 18.5 20 22 30 37 44 52 Type TD125U TD125U TD125U TD125U
TD125U TD125U TD125U TD125U TD125U TD125U TD125U TD125U TD125U
TD125U TD125U TD125U TD125U TD125U

MCCB Rating Ir (A) 15 15 15 15 15 15 15 15 15 15 15 20 20 30 40
40 50 80

Contactor Type MC-9 MC-9 MC-9 MC-32 MC-32 MC-40 MC-40 MC-40
MC-40 MC-40 MC-40 MC-40 MC-40 MC-40 MC-85 MC-85 MC-85 MC-85

Thermal overload relay Type MT-32 MT-32 MT-32 MT-32 MT-32 MT-63
MT-63 MT-63 MT-63 MT-63 MT-63 MT-63 MT-63 MT-63 MT-95 MT-95 MT-95
MT-95 Setting range (A) 1-1.6 1-1.6 1.6-2.5 2.5-4 2.5-4 4-6 5-8 6-9
7-10 9-13 12-18 16-22 16-22 16-22 24-36 28-40 34-50 45-65

A-4-19

Technical informationProtective coordination SCCR according to
UL489

MCCB

MC Performance: Ue=600V MCCB TD125U NU 50kA HU 100kA TOR

Motor hp (kW) 0.49 (0.37) 0.737 (0.55) 1.005 (0.75) 1.474 (1.1)
2.01 (1.5) 2.95 (2.2) 4.02 (3) 4.959 (3.7) 5.36 (4) 7.37 (5.5)
10.05 (7.5) 12.06 (9) 14.745 (11) 20.11 (15) 24.80 (18.5) 29.49
(22) 33.51 (25) A 0.6 0.9 1.1 1.5 2 2.8 3.8 4.4 4.9 6.6 8.9 10.6
11.5 14 17.3 21.3 25.4 Type TD125U TD125U TD125U TD125U TD125U
TD125U TD125U TD125U TD125U TD125U TD125U TD125U TD125U TD125U
TD125U TD125U TD125U

MCCB Rating Ir (A) 15 15 15 15 15 15 15 15 15 15 15 15 15 15 20
25 32

Contactor Type MC-9 MC-9 MC-9 MC-9 MC-32 MC-32 MC-32 MC-40 MC-40
MC-40 MC-40 MC-85 MC-85 MC-85 MC-85 MC-85 MC-85

Thermal overload relay Type MT-32 MT-32 MT-32 MT-32 MT-32 MT-32
MT-32 MT-63 MT-63 MT-63 MT-63 MT-95 MT-95 MT-95 MT-95 MT-95 MT-95
Setting range (A) 0.4-0.63 0.63-1 1-1.6 1-1.6 1.6-2.5 2.5-4 2.5-4
4-6 4-6 5-8 7-10 9-13 9-13 12-18 16-22 18-25 24-36

A-4-20

Technical informationHow to calculate short-circuit current
value Various short-circuitThe purpose of calculating short circuit
values Selection of circuit breakers, fuse. Adjusting metering
devices Consideration for mechanical resistance Consideration for
thermal resistance Various value of short-circuit current should be
applied to the tests for upper factors. Symmetrical current for AC
and asymmetrical current for DC are used for classifying short
circuit current. Their differences should be essentially considered
in the basic step of making network plan. Symmetrical short-circuit
current real value Short-circuit current is composed of AC and DC
as it shows on . The short-circuit which indicates the real value
of AC is called as symmetrical short-current real value, l
(rms)sym. This current is the essential factor of selecting MCCB,
ACB, fuse.AC+ DC (asymmetrical short-circuit current) DC AC

3-phases average asymmetrical shortcircuit current real value: l
(rms)ave Each phase is different in its input current value in 3
phases circuit. So that AC rate for 3 phases is different. This
value is the average of asymmetrical short-circuit current of 3
phases. And with symmetrical short-circuit current real value and
short-circuit power factor, we can achieve the value, and 3-phases
average asymmetrical short circuit current real value is calculated
with this formula. l (rms)ave= (rms)sym l Maximum asymmetrical
short-circuit current instantaneous value: lmax Each phase has
different instantaneous current value. And when asymmetrical
short-circuit current shows its maximum instantaneous value, the
current value is called as maximum asymmetrical short-circuit
current instantaneous value. This current is to test the mechanical
strength of serial equipments. And with symmetrical short-circuit
current real value and short-circuit power factor, we can achieve
the value, and maximum asymmetrical short-circuit current
instantaneous value is calculated with this formula. lmax= (rms)sym
l

Composition of short-circuit current

Maximum asymmetrical short-circuit current real value: l
(rms)asym The short-circuit which indicates the real value of DC is
called as asymmetrical short-circuit current real value. And this
current value is changeable upon the short-circuit closing phase.
This current value is treated for checking the thermal resistant
strength of wrings, CT and etc. With symmetrical short-circuit
current real value and short-circuit power factor, we can achieve
the value, from . and maximum asymmetrical short-circuit current
real value is calculated with this formula. l (rms)asym= (rms)sym
l

Network impedance for calculating shortcircuit current value
Bellows should be considered for the calculation as the impedance
components affecting circuit to trouble spot from shortcircuit
power. a. Primary part impedance of incoming transformer Its
calculated from the shortcircuit current data which is provided by
power supplier. Calculated value can be regarded as reactance. b.
Impedance of incoming transformer Its amount is upon the capacity
of transformer and primary voltage. Generally this impedance can be
regarded as reactance and refer to , .

A-4-21

Technical informationHow to calculate short-circuit current
value Various short-circuitc. Reactance of motor Motor works as
generator and supply short circuit current in the condition of an
accident circuit such as . Generation factor of firm motor should
be considered in a low voltage circuit where a circuit breaker
operates quickly and in a high voltage circuit for the selection of
fuse. Reactance of motor can be regarded in the range of 25%
normally. d. Distribution impedance Impedance of cable and busduct
do control short-circuit remarkably in low voltage network. Refer
to , . e. Others MCCB, ACB CT are equipments for the network of low
voltage. The impedance of these equipment which is calculated from
short-circuit current value should be considered. Generally, the
impedance of those equipment is that of rated current (normal
condition), if operators apply that impedance value, bigger
reactance value may be applied to calculated short-circuit current
value.Interphase voltage Between RS Between ST 400V 30kW
Short-circuit

Between TR R current S current T current

Short-circuit of motor

A-4-22

Technical informationHow to calculate short-circuit current
value With percent impedanceOhm formula (), percent impedance
formula (%), unit formula (per unit) can be applied to calculate
short-circuit current value. Ohm formula [] Short-circuit current
value is calculated by converting into ohm value [] Percent
impedance formula (%) Each impedance is converted into the
impedance of base value and base voltage. And the required amount
for electric demand should be shown as percent unit. And apply that
value in ohm formula. Unit formula The base value equals 1.0. and
all value of network shows in the way of decimal system. Applying
any of upper calculation formulas to achieve short-circuit current
value, it shows equal value. To select a certain formula for doing
it, operator can select one of those formula which is proper to
oneself. Below is percent impedance formula. Finding base value The
rated current of transformer shall be the base value. Base capacity
PB= PT kVA Base voltage VB= VT V Base current IB= IT = PT 103 A 3VT
V V = PB103 PT1032 B 2 T

Converting impedance into base value a. Primary part impedance
of transformer: %X1 PB %X1= 100 % Q103Q: Primary part short-circuit
capacity

b. Impedance of transformer: %ZT It generally indicates as
percent impedance. If base capacity is equal to transformer
capacity, %ZT can be used as it is. When base capacity is not equal
to transformer capacity, convert values by this formula. PT PB =
%ZT %ZB%: value converted by base value

1phase transformer should converted into the value of 3 phase
transformer, And the percent impedance is equal to 3 2 calculated
urgent value. c. Reactance of motor: %Xm Transformer capacity shows
the value in kW, so it is converted into unit, kVA. (kVA value)
1.5(Output of motor, kW) %Xm= 25% Converting it from base capacity
PB PM = %Xm %Xm(Converting formula for different capacity)

d. Impedance of busduct, cable Cable: Area of cross-section
& length Busduct: Rated current In , ZC = ( per each unit
length)(length) [] Convert this value into % value. %ZC = ZC ZB

Base impedance ZB=

(% converting formula)

2cables in same dimension, its recommendable to divide the
length by 2.

Base value

A-4-23

Technical informationHow to calculate short-circuit current
value

Preparing a impedance map Prepare impedance map according to the
impedance value from (2). Various electricity suppliers like
source, motor have same electric potential in impedance map. As you
find it on (a), extend it from the unlimited bus to fault point,
draw impedance map.

In case of 1 phase short-circuit Current value from (5)
multiplied by 3 2

Each short-circuit current value (1)= 3 2 (3phases short-circuit
current)(or )

Calculating impedance Calculate impedance as in impedance map
< Fig.4 (a)> %Z = %R + j %X %Z = (%R)2+ (%X)2

Calculating symmetrical short-circuit current real value

Base value

Calculating various short-circuit current value IF (3) = IF
(rms)sym (3) = = P B10 3 100 3VB%Z IB 100 A %Z

Calculate various short-circuit current value with values from
like , , %R short-circuit power factor cos = %Z 3 phases average
asymmetrical real value IF (rms)ave= (rms)sym IF Maximum average
asymmetrical real value IF (rms)asym=IF (rms)sym Maximum
asymmetrical instantaneous value IFmax= (rms)sym IF

A-4-24

Technical informationHow to calculate short-circuit current
value With a simple formulaFor its special cases, calculating exact
value should be needed, in the other hand, for the practical use,
we recommend simple formula. Finding a base value It shall be the
rated current of transformer. PB= PT [kVA] VB= VT [V] IB= IT [A]
VTB [] ZB= PT103Ref 1) Calculation in the random voltage E Voltage
line which is mostly close to E shall be selected to calculate it .
i.e. in case of 220V, (200V line value)200/220 Ref 2) Calculation
for a certain impedance Zt (%) Impedance line which is mostly close
to Zt (%) shall be selected to calculate it. i.e. 420V, Zt= 4.5%
%Z=4% Line value (or 5% line) 4 (or 5)/4.5 Ref 3) When the value is
out of lines or over 200VA or below 100kA, multiply 10 times to the
calculated values. Transformer capacity and short-circuit current
Base value

Short-circuit current from incoming circuit Disregard the
impedance value of primary part of transformer. Calculate
short-circuit current value according to . (If the impedance value
of primary part of transformer is considered, calculate the current
value as below formula) IA (R)= IB (%RT)2+ (%X1+%XT)2 PB 100 [%]
Q103 100 A

Short-circuit current to motor IA (M)= 4 (Rated current of
motor) Symmetrical short-circuit current at point A IA= IA (R)+IA
(M) Decreasing coefficient caused by busduct IA Obtaining the value
of 10VT Calculate decreasing coefficient from Decreasing
short-circuit current by reactance When theres 1phase transformer
in a certain circuit, calculate it in the base of reactance.
Regarding the reactance as pre-impedance at source part at point of
, EB XC = 3 IC Reactance C~D: XD[] (impedance of 1 T)

%X1 =

If the value of %RT is not clear, %ZT%TT IA (R) = IB 100 A
%X1+%XT

A-4-25

Technical informationHow to calculate short-circuit current
value

Calculating the value of XD/XC and decreasing coefficient d from
the reactance of . Current at point D ID=dIC Impedance of 1 phase
transformer XD= X (1) 1 2 a. Short-circuit current at EC voltage
base ID (rms)sym3= dIC (rms)sym3 b. Short-circuit current at ED
voltage base ID (rms)sym3= dIC (rms)sym3EC/ED

1 phase short-circuit (Each current)= 3 3 phases short-circuit
current 2 (or )

General busduct Decreasing coefficient of short-circuit current
by reactance: dBusduct Ratings (A) Material Size [mm] [/m]
Resistance Reactance Impedance R X Z [/m] [/m] [/m]

Coefficient d for cables ID Calculating the value of 10VT
Decreasing coefficient b value is calculated from . For insulator
drawn wrings, we can find the value directly from . Calculating
symmetrical short-circuit current real value IF (rms)sym= bID[D]
Various short-circuit current In case of having short-circuit
current power factor, find , , from , If not find 3 values from 3
phases short-circuit asymmetrical current average value IF IF
(rms)ave= (rms)sym Maximum asymmetrical real value IF (rms)ave=
(rms)sym IF Maximum asymmetrical instantaneous value IF (rms)ave=
(rms)sym IF , , values when short circuit power factor value is not
definite.Symmetrical short-circuit real value (A) Variables Maximum
asymmetrical real value 3 phases short-circuit asymmetrical current
average value Maximum asymmetrical instantaneous value

200 400 600 Cu 800 1000 1200 1500

325 640 650 675 6100 6125 6150

2.4110-4 1.31210-4 2.7410-4 0.75110-4 1.0210-4 1.26710-4
0.60710-4 0.9110-4 1.09410-4 0.41210-4 0.7210-4 0.83010-4 0.31510-4
0.6010-4 0.67810-4 0.26110-4 0.51610-4 0.57810-4 0.22110-4
0.44910-4 0.50010-4

2000 61252 0.12910-4 0.7910-4 0.80010-4 Decreasing coefficient
of general busduct (Cu)

Decreasing coefficient b in cable (600V IV)

2500 25015000 50011000 100115000 1500125000 25000

1.0 1.03 1.13 1.18 1.25 1.33

1.0 1.02 1.07 1.09 1.13 1.17

1.48 1.64 1.94 2.05 2.17 2.29

Decreasing coefficient b in cable (600V IV)

A-4-26

Technical informationHow to calculate short-circuit current
value Calculation exampleCalculation1) Short-circuit current value
will be achieved by simple formula and percent impedance formula
for

Percent impedance formula (1) Base value PB = 750kVA VB = 420V
IB = 1031A ZB = 0.237 (2) Each impedance a. Reactance at primary
part of transformer %X1= 750 100= 0.075 % 1000103 e. Impedance of
cable Converting impedance of whole metal tube [2100mm2 10m] %
%RC1= 0.0001810 1 100= 0.38 0.237 2 1 %XC1= 0.0001310 100= 0.27 %
0.237 2 [125mm2 20m] % %RC2= 0.0001420 100= 1.18 0.237 %XC2=
0.0001320 100= 1.09 % 0.237 [250mm2 50m] % %RC3= 0.0000750 100=
1.47 0.237 %XC3= 0.0001350 100= 2.74 % 0.237 [14mm2 30m] % %RC4=
0.0001330 100= 16.45 0.237 %XC4= 0.0001530 100= 1.88 % 0.237

b. Impedance of transformer %RT= 1.4% %XT= 4.8% c. 1Tr impedance
%RT1 = 1.15750 20 1.68750 %XT1 = 20 1 = 21.6 % 2 1 = 31.5 % 2

d. Reactance of transformer 750 1201.5 750 %Xm2 = 1401.5 750
%Xm3 = 1001.5 750 %Xm4 = 1151.5 %Xm1 = 25= 104 % 25= 89 % 25= 125 %
25= 108.7 %

A-4-27

Technical informationHow to calculate short-circuit current
value

(3) Preparing a impedance map Connect short-circuit supplier to
the unlimited bus.

IF2 (rms)sym is short-circuit current. Therefore, convert it
into 1 phase short-circuit current. 3 IF2 (rms)1sym= 7989 = 6919 A
2 39.06 = 0.72 cos2= 54.2

Unlimited bus

(6) Various short-circuit current Calculate from . , , a. Fault
point F1 cos1= 0.422 1.05 1.3 1.74 = = = IF1 (rms)ave= 1.0316900=
17407 A IF1 (rms)asym= 1.0516900= 17745 A IF1max= 1.7416900= 29406
A b. Fault point F2 cos2= 0.72 1.0 1.48 = = IF21 (rms)asym= 1.06919
A IF21max= 1.486919= 10240 A

Calculating impedance Calculate it in serial/parallel type
formula

Simple calculation formula (1) Base value PB = 750kVA VB = 420V
IB = 1031A ZB = 0.237

a. Fault point F1

b. Fault point F2

(2) Short-circuit current of incoming circuit Disregard the
impedance of primary part of transformer In IA (R)= 20500 A (3)
Short-circuit current of motor Sum of motor capacity=
(120+140+100+115)1.5= 713 kVA IA (M) = 713 3420 4= 3920 A

%Z1=

(2.57)2+ (5.53)2

%Z2=

(39.06)2+ (37.55)2 (4) Symmetrical short-circuit current at
point A IA = 20500+3920= 24420 A

= 6.1[%]

= 54.2[%]

(5) Calculation of asymmetrical short-circuit current a. Fault
point F1 1031 IF1 (rms)sym = 6.1 100= 16900 A 2.57 = 0.422 cos1 =
6.1 b. Fault point F2 (1 phase circuit) 1031 IF2 (rms)sym = 100=
1902 A (at 100V) 54.2 = 1031 100 420 = 7989 A (at 420V) 54.2
100

A-4-28

Technical informationHow to calculate short-circuit current
value Calculation example(5) Decreasing short-circuit current for
cable a. At point F1 2100mm2 10m 2100mm2 10m= 100mm2 5m IA 2024420
= = 29.1 10420 10E Coefficient b= 0.935 Short-circuit current value
at point C Ic (rms)sym= 0.93524420= 22850 A 125mm2 20m IC 2022850 =
= 108.9 10420 10E IF1 (rms) sym= 0.785244850= 17940 A b. At point
F1 14mm2 30m IC 3024420 = = 174.4 10420 10E Coefficient b= 0.249 ID
(rms)3sym= 0.2424420= 6080 A Decreasing by the reactance (1Tr)dp
Convert the value of %X of 1Tr to base capacity XD= 7502/20= 75%
Impedance of primary part at 1Tr XA = IB 1031 100 = 100[%] 6080 ID
(6) Various short-circuit current Find , , from a. At point F1 1.25
1.13 2.17 = = = IF1 (rms)ave= 1.1317940= 20272 A IF1 (rms)asym=
1.2517940= 22425 A IF1max= 2.1717940= 38930 A b. At point F2 1.13 =
1.94 = IF21 (rms)asym= 1.137076= 7945 A IF21max= 1.947076= 13727 A
Comparison of short-circuit

Fault pointSymmetrical short-circuit current real value 3 phases
average asymmetrical current real value Maximum asymmetrical
current real value Percent impedance calculation value Simple
formula calculation value Percent impedance calculation value
Simple formula calculation value Percent impedance calculation
value Simple formula calculation value

F1

F2

16900A 6919A 17940A 7076A 106% 102% 17407A 20272A 116% —

17745A 6919A 22425A 7995A 126% 115%

Convert XD to equivalent 3 phases, and XD/2 75026080 = = 2.21 XA
2021031100 Coefficient d of d= 0.32 IF2 (rms)3sym= 0.326080=1945 A
(400V) = 0.326080420/100 = 817 [A] (100V) IF2 (rms)1 sym= 8171 3 =
7076 A 2

A-4-29

Technical informationHow to calculate short-circuit current
value

Short-circuit current value will be achieved by simple formula
for Z1=0.25%(1000kVA) A Z2=0.01%(1000kVA) Tr2 500kVA 6.6/3.3kV
Z3=4%

Short-circuit current at point B: ISB a) Impedance Map Serial
sum of impedance Ztot= 0.25+0.01+8= 8.26 %

tot = 0.25+0.01+8 = 8.26 %

B M 100kW M 200kW Tr2 100kVA 3.3kV/220V Z4=2.5% 20kWu=8.5%
cos=0.8 1000kVA Z5=1.0% M 1000kVA Z5=1.0%

b) Short-circuit current ISC = 2118 A 33.3 kV 10008.26 Breaking
capacity of breaker [MVA] MVA= 3 short-circuit current [kA] line to
line voltage[kV] ISB= Short-circuit current at point C: ISC a)
Impedance Map 1000 kVA 1000100

M

M

(1) Calculate rated current at each point Rated current InA at
point A InA= 500 kVA 1000 36.6 kV 1000 Rated current InB at point B
InB= 100 kVA 1000 33.3 kV 1000 InC= 20 kW 1000 3220 V 0.850.8 =
43.7 A

= 17.5 A Parallel sum of impedance Z= 1 = 32.58 % 1 1 1 + 2001 +
8001 33.26

= 77.2 A

(2) Put 1000k VA for base capacity and calculate short-circuit
current at each point. Short-circuit current ISA at point A a)
Impedance Map

b) Short-circuit current ISC ISC= 1000 kVA 1000100 = 8055 A 3220
V 32.58 %

Incoming 25%

Calculation formulaZ=0.25(%)

Rated current In =

Transformer capacity 3Rated voltage Transformer capacity100
3Rated voltage%Z

b) Short-circuit ISA ISA= 1000 kVA 1000100 36.6 kV 10000.25% =
34990 A

Short-circuit current Is =

Breaking capacity of breaker [MVA] MVA= 3 short-circuit
current[kA] line to line voltage[kV]

A-4-30

Technical informationHow to calculate short-circuit current
value Combination of transformer and impedance Combination of
transformer and impedanceTransformer Impedance 3 phases transformer
6.3kV/210V Oil Tr. 6.3kV/210V Mold Tr. 20kV/420V Mold Tr. 20kV/420V
Oil Tr. XT[%] ZT[%] RT[%] XT[%]

Transformer capacity (VA) ZT[%] RT[%] XT[%] ZT[%] RT[%] XT[%]
ZT[%] RT[%] 20 2.19 1.94 1.03 30 2.45 1.92 1.53 4.7 2.27 4.12 50
2.47 1.59 1.89 4.7 1.94 4.28 75 2.35 1.67 1.66 4.4 1.56 4.11 100
2.54 1.65 1.96 4.6 1.5 4.24 150 2.64 1.64 2.07 4.2 1.29 4.0 200 2.8
1.59 2.31 4.5 1.17 4.35 300 3.26 1.46 2.92 4.5 1.2 4.33 500 3.61
1.33 3.36 4.7 0.08 4.69 5.0 1.56 750 4.2 1.55 3.9 6.0 0.8 5.95 5.0
1.40 1000 5.0 1.35 4.82 7.0 0.7 6.96 5.0 1.26 1500 5.1 1.22 4.95
7.0 0.6 6.97 5.5 1.2 2000 5.0 1.2 4.85 7.5 0.65 7.47 5.5 1.1

4.76 4.80 4.84 5.37 5.39

6.0 6.0 6.0 7.0 7.0

1.0 0.9 0.8 0.75 0.7

5.92 5.93 5.95 6.96 6.96

Example of transformer impedanceTransformer Impedance
Transformer capacity (VA) 10 20 30 50 75 100 200 300 500 750 1000
2000 3000 5000 7500 10000 15000 20000 30000 50000 75000 100000
150000 200000 300000 500000 1 phase transformer 6.3kV/210V Oil Tr.
6.3kV/210V Mold Tr.

Example of cable impedance (600 vinyl cable)Impedance of cable
1m () Internal Internal insulation Cable vinyl tube wiring or
dimension wiring of cable of steel tube steel tube and duct and
duct 1.6mm 2mm 3.2mm 0.00020 0.00012 5.5mm2 8mm2 14mm2 22mm2
0.00015 0.00010 30mm2 2 38mm 50mm2 60mm2 80mm2 100mm2 125mm2
0.00013 0.00009 150mm2 200mm2 250mm2 325mm2 Resistance () / cable
1meter 0.0089 0.0056 0.0022 0.0033 0.0023 0.0013 0.00082 0.00062
0.00048 0.00037 0.00030 0.00023 0.00018 0.00014 0.00012 0.00009
0.00007 0.00005

ZT[%] RT[%] XT[%] ZT[%] RT[%] XT[%] 14.9 14.0 14.8 13.6 11.0
8.87 7.70 5.75 5.08 5.05 4.03 4.55 4.29 3.26 2.72 2.33 2.04 1.90
14.9 14.0 14.8 13.6 11.0 8.85 7.68 5.69 4.97 4.92 3.93 4.50 4.22
3.18 2.81 2.18 1.82 1.60 0.268 0.503 0.523 0.494 0.558 0.562 0.571
0.619 1.05 1.16 0.904 0.637 0.768 0.725 0.775 0.823 0.937 1.02

Insulator wiring in building

0.00031

0.00026

2.5 2.37 2.57 2.18 2.05 2.27 2.48 3.39 3.15 2.23 4.19

2.07 1.84 1.76 1.58 1.47 1.46 1.49 1.31 1.31 1.28 1.09

1.40 1.49 1.87 1.50 1.42 1.74 1.98 3.13 2.87 2.96 4.03

0.00022

At 60Hz, the reactance multiply 2 times itself, so 1/2 reactance
of primary part can achieve IB. When the cable is parallelly 2 or
3ea, reactance and resistance can be calculated in the condition of
1/3 and 1/3 length cable.

A-4-31

Technical informationHow to calculate short-circuit current
value Various short-circuit Impedance sample of bus and busduct
(50Hz)Ampere rating (A) 600 800 1000 1200 1350 1500 1600 2000 2500
3000 3500 4000 4500 5000 50Hz R 1.257 0.848 0.641 0.518 0.436 0.378
0.360 0.286 0.218 0.180 0.143 0.126 0.120 0.095 X 0.323 0.235 0.185
0.152 0.129 0.113 0.107 0.084 0.065 0.054 0.042 0.038 0.036 0.028 Z
1.297 0.879 0.667 0.540 0.454 0.394 0.375 0.298 0.228 0.188 0.149
0.131 0.125 0.099 R 1.385 0.851 0.645 0.523 0.443 0.386 0.367 0.293
0.221 0.184 0.146 0.129 0.122 0.098 60Hz X 0.387 0.282 0.222 0.183
0.155 0.135 0.128 0.101 0.078 0.064 0.051 0.045 0.043 0.034 Z 1.438
0.896 0.682 0.554 0.469 0.409 0.389 0.310 0.235 0.195 0.155 0.136
0.130 0.103[10-4/m]

Impedance sample of Bus and busduct (50Hz)Ampere rating (A) 600
800 1000 1200 1350 1500 1600 2000 2500 3000 3500 4000 4500 5000
5500 6500 50Hz R 0.974 0.784 0.530 0.405 0.331 0.331 0.282 0.235
0.166 0.141 0.122 0.110 0.094 0.082 0.078 0.068 X 0.380 0.323 0.235
0.185 0.152 0.152 0.129 0.107 0.076 0.065 0.056 0.051 0.043 0.038
0.035 0.028 Z 1.045 0.848 0.580 0.445 0.364 0.364 0.311 0.259 0.182
0.155 0.135 0.121 0.104 0.091 0.086 0.074 R 0.977 0.789 0.536 0.412
0.338 0.338 0.289 0.241 0.169 0.144 0.127 0.113 0.096 0.084 0.080
0.071 60Hz X 0.456 0.387 0.282 0.222 0.183 0.183 0.155 0.128 0.091
0.078 0.068 0.061 0.052 0.045 0.043 0.031

[10-4/m]

Z 1.078 0.879 0.606 0.468 0.384 0.384 0.328 0.273 0.192 0.164
0.143 0.126 0.109 0.096 0.091 0.077

A-4-32

Technical informationHow to calculate short-circuit current
value Calculation exampleUsing a certain graph, you can find and
calculate the short-circuit current value which is at one position
of network. No matter the condition of network is different, you
can do the calculation through adjusting variables. Graph note P
coordinatesTransformer capacity (kVA) Is 1 coordinatesShort-circuit
current value (kA) Is 2 coordinatesShort-circuit current value
affected cable condition (kA) Line — % impedance of transformer (%)
Line — Length of cable (m) Line — Square mm of cable (mm2) Line —
Is2 (kA)Remark) line shows the length of hard vinyl cable (600V
IV)

How to calculate short-circuit current value (1) 3 phases
transformer Short-circuit current value at (A) where it is just
below transformer. At P coordinates, find the coordinates value (g)
of the cross point (f) which is from transformer capacity (e) and A
line. Disregard primary part impedance of transformer. Find the
short-circuit current value at Point B, C which are considered
cable impedance. At short-circuit current g (kA) of Is 1
coordinates, find the value (h) of B line Move (h) to parallel
direction of Is, and find the cross point (i) to C line. Move (i)
to parallel direction of Is2, and find the cross point value (j) to
D line (g), finally find (k) of Is2

(2) 1 phase transformer Short-circuit current value where it is
just below transformer. Find the value as same as that of 3 phase
transformer and multiply it 3 times. (gkA) Find the short-circuit
current value where it is considered cable impedance. Multiply 2/3
times to g of Is coordinates Find the Is2 value as same as that of
3 phase transformer and multiply it 3/2 times.

Remark 1. Its not considered the transformer contribution.
Multiply 4 times the rated current of transformer in cases. 2. The
real short-circuit current value is littler lower that its
calculated value by the way we suggest because