Selection criteria of all cb's

Masterpact - Compact - multi 9How to choosea circuit breaker ?

Merlin Gerin Square D Telemecanique

DBTP55EN-03/97M9CF6BEN-03/97


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How to choose a circuit breaker ? Summary

2 Function of a Circuit Breaker 4 Introduction 11 Criteria of choice 16 Low voltage network 17 Main LV switchboard 20 Air circuit breaker : definition 22 Air circuit breaker 29 Sub distribution board 32 Moulded case circuit breaker 38 Final distribution board 41 Miniature circuit breaker 48 Conclusion


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How to choose a circuit breaker ? Function of a circuit breaker

Protect cables against overloads and short circuits

Let the current flow without overbreaking Open and close a circuit under rated current Protect against insulation faults

(with an integrated earth leakage device)

To guarantee The dependability of the installation the end-user's

safety

Basic function of a circuit breaker


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How to choose a circuit breaker ? Introduction

Mechanical system to open and close the circuit

Composed of a trip unit A bimetal strip to act against overloads, A magnetic trip to act against short circuits, Or a electronic trip unit to act against both the

fault currents.

Composed of a switching device

A switching device A trip unit


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How to choose a circuit breaker ? IntroductionThree types of circuit breaker:

Air circuit breaker Moulded case circuit breaker Miniature circuit breaker


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How to choose a circuit breaker ? Low voltage networkSources

Main LV switchboardLevel 1a

Level 1b

Level 2

Level 3

Loads

or

a

Final distribution board

Sub distribution board


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How to choose a circuit breaker ? Main LV switchboardLevel 1a: the upper level

Incoming devices Bus couplers High rated outgoingsThe level of the industrial circuit breaker

Level 1a

Level 1b

or

a


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How to choose a circuit breaker ? IntroductionA circuit breaker also fulfils other functions :Isolation function according to IEC 947.2 standard

M32 H1Ui 1000 50/60HzUe 380/440V 480/690VIcu 100kA 85kAIcs 100kA 85kAIcw 75kA 1s

IEC947-2

masterpact

multi9

C25400Va6000

10kA IEC 947.2

220/240 85380/415 36440 35500 30660/690 8250 50cat AIcs=100% Icu

IEC947-2UTE VDE BS CEI UNE NEMA

1 3

2 4


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How to choose a circuit breaker ? IntroductionA circuit breaker also fulfils other functions :Remote control and automatic transfer switches


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How to choose a circuit breaker ? IntroductionA circuit breaker also fulfils other functions :Metering and communication


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How to choose a circuit breaker ? Introduction

...how to choose between all these breakers ?


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How to choose a circuit breaker ? Criteria of choice

To the required needs At the right cost

And... several criteria of choice

A step-by-step process in order to selectthe right circuit breaker


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Rating I, U, F, ... Breaking capacity Number of poles (grounding system) Standards (IEC, UL, JIS, ...) Type of loads to be protected (cable, busbar,

generator, motor, direct current devices)

"Basic" criteria


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Earth leakage protection Isolating function Positive break indication Front face double insulation Locking Interlocking Limiting technology

"Dependability" criteria


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Selectivity Draw-out possibility Maintenability

"Continuity of service" criteria


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Cascading Reverse feeding without derating Field installable auxiliaries

"Comfort" criteria Simple to install, easy to work with Evolutive network (modular system) Network monitoring, communication

"Performing" criteria


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How to choose a circuit breaker ? Low voltage networkSources

Main LV switchboard

Sub distribution board

Final distribution board

Level 1a

Level 1b

Level 2

Level 3

Loads

or

a

MCCB area

ACB and High Power MCCB area

MCB area


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How to choose a circuit breaker ? Main LV switchboardLevel 1a: the upper level

Incoming devices Bus couplers High rated outgoingsThe level of the industrial circuit breaker

Level 1a

Level 1b

or

a


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How to choose a circuit breaker ? Main LV switchboard

Very high nominal current (thousands of amps) High level of short circuit Continuity of service selectivity possibility of maintenance draw-out choice Gen-set synchronisation Interlocking Network monitoring

Level 1a requirements


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How to choose a circuit breaker ? Air circuit breaker

Ratings up to: 6300 A

Comply with standards: IEC 947.2

Levels of breaking capacity: high (up to 150 kA)

Icu / Ics: 100 %

Electrodynamical withstand: high

Level of selectivity: max

Main contact / pole design: blow closed

Stored energy mechanism ? yes

Isolating case: opened

Trip unit: solid state

ACB standard basic design


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How to choose a circuit breaker ? Air circuit breakerACB standard installation size: large

Positioning: horizontal

Connection: rear

Draw-out type: 90 %


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How to choose a circuit breaker ? Air circuit breakerACB standard installation Endurance cycle : medium

Inspection possibility ? yes

Main tenance requirement: high

Maintenance possibility ? yes


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How to choose a circuit breaker ? Main LV switchboard

This is the "air circuit breaker" field


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How to choose a circuit breaker ? Air circuit breaker: definition

Industrial networks: several types

Hybrid circuit breaker

Power circuit breaker

Moulded case circuit breaker

Links ?

Air circuit breaker


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How to choose a circuit breaker ? Air circuit breakerMasterpact basic design Ratings up to: 6300 A

Comply with standards IEC 947.2and others standards(UL, ANSI, JIS,...)


Icu / Ics: 100 %

Electrodynamical withstand: very high

Level of selectivity: total (N1 and H1 types)

Main contact / pole design: blow closed

Stored energy mechanism ? yes

Isolating case: closed

Trip unit: solid state (RMS)


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How to choose a circuit breaker ? Air circuit breakerMasterpact installation size: optimized

Positioning: horizontal

Connection: rear

Draw-out type: 90 %


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How to choose a circuit breaker ? Air circuit breakerMasterpact installation Endurance: very high

Inspection possibility ? yes

Maintenance requirement: low

Maintenance possibility ? yes


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How to choose a circuit breaker ? Air circuit breakerMasterpact Compact size

Isolating case

High endurance

RMS electronic trip units


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How to choose a circuit breaker ? Sub distribution boardLevels 1b and 2: the medium level

Low rated outgoing of the main LV swichboard Sub-distribution switchboardStill the level of the industrial circuit breakers

Level 1b

Level 2


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How to choose a circuit breaker ? Sub distribution board

Medium nominal current (hundreds Amps, 40°C)

High level of short-circuits (up to 150kA)

Limitation of the effects of the electrical faults

Frequent operations

No need of maintenance

Additional functions

Levels 1b and 2: requirements


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How to choose a circuit breaker ? Sub distribution board

This is the "moulded case circuit breaker" field


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How to choose a circuit breaker ? Moulded case circuit breaker



Levels of breaking capacity: high (150 kA)

Icu / Ics: 50 %

Electrodynamical withstand: low (15 x In)

Level of selectivity: limited

Main contact / pole design: blow open

Stored energy mechanism ? no

Isolating case: moulded

MCCB standard basic design


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How to choose a circuit breaker ? Moulded case circuit breaker




Icu / Ics: 100 % up to 630 A for N, H, L

50 % for N and H ranges from 800 Ato 1250 A

Electrodynamical withstand: low

Level of selectivity: high

Main contact / pole design: blow open

Stored energy mechanism ? no

Isolating case: moulded

Compact basic design


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How to choose a circuit breaker ? Moulded case circuit breakerMCCB standard installation Compact size: yes

Positioning: vertical

Connection: front

Draw-out type: 10 %


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How to choose a circuit breaker ? Moulded case circuit breakerCompact installation Compact size: yes

Positioning: vertical, horizontal

Connection: front, rear

Draw-out type: option


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How to choose a circuit breaker ? Moulded case circuit breakerMCCB standard utilisation Endurance: high

Inspection possibility ? no

Maintenance requirement: low

Maintenance possibility ? no


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How to choose a circuit breaker ? Moulded case circuit breakerCompact utilisation Endurance: high

Inspection possibility ? no

Maintenance requirement: very low

Maintenance possibility ? no


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How to choose a circuit breaker ? Final distribution boardLevel 3: final level

Low rated outgoings Distribution board From industrial applications to residential

appplications

Level 3

Loads


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How to choose a circuit breaker ? Final distribution board

MCB shall comply with domestic and industrial standards

Low current (up to 125 A , 20°, 30°, 40°C)

Limitation of the effects of the electrical faults

From low level to Medium level of short-circuits (from 3 to 50 kA)

MCB shall be of the isolating type

MCB shall meet the requirements for current discimination

No need of maintenance additional functions (as auxiliaries and accessories)

Level 3: requirements


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How to choose a circuit breaker ? Final distribution board

This is the "miniature circuit breaker" field


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How to choose a circuit breaker ? Miniature circuit breaker

Mounting system: 35 mm symmetrical rails

Comply with standards: IEC 898/EN 898IEC 947.2/EN60947.2IEC 1009/EN 61009

Ratings: from 1 to 80 A

Levels of breaking capacity: low (10 kA)

Icu / Ics: 50 %

Current limiting: class 3


Insulation and isolation: positive contact indication

Additionnal function accessories, auxiliaries

MCB standard basic design


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Mounting system: 35 mm DIN type

Comply with standards: IEC 898/EN 898IEC 947.2/EN60947.2IEC 1009/EN 61009UL/CSA

Ratings: from 0,5 to 125 A

Levels of breaking capacity: up to 50 kA

Icu / Ics: up to 75 %

Current limiting: class 3


Insulation and isolation: positive contact indication/UIMP = 6 kV

Additionnal function yes

Multi 9 basic design


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How to choose a circuit breaker ? Miniature circuit breakerMCB standard installation Miniature size: yes


Connection: front, rear

Power supply connections: up and downstream

Large incoming / outgoingterminals: yes

Locking screw: flat, recessed head screws

DIN rail system: yes


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How to choose a circuit breaker ? Miniature circuit breakerMulti 9 MCB installation Miniature size: yes


Connection: front, rear, connection

combs

Power supply connections: up and downstream

Large incoming / outgoingterminals: tunnel type terminal

Locking screw: flat, recessed head screws, positive

DIN rail system: 35 mm symmetrical rail


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How to choose a circuit breaker ? Miniature circuit breakerMCB standard installation Electrical endurance: high

Mechanical endurance : high

Operating temperature: – 5° C to 45° C

Degree of protection: IP 40

Auxiliary function: yes

Possibility of earth leakageprotection: yes

Accessories: yes


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How to choose a circuit breaker ? Miniature circuit breakerMulti 9 MCB utilisation Electrical endurance: greater than

requirements

Mechanical endurance : greater thanelectrical endurance

Operating temperature: – 5° C to 60° C

Degree of protection: IP 40 (in accordance with IEC 947.1)

Auxiliary function: position indication, alarm switch, under voltage trip, shunt trip

Possibility of earth leakageprotection: yes, with added unit

Accessories: locking facilities, marking connection combs


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Timers Contactors Impulse relays Surge arresters Push buttons Lamps Enclosures...

With also a range of complementary products:


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How to choose a circuit breaker ? ConclusionThe right choice

From 1 up 6300 A, Schneider Electric circuitbreaker ranges meet the most severerequirements

Selection criteria of all cb's

Engineering

Transcript of Selection criteria of all cb's