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Safety clearances

During a short-circuit interruption, high temperatures, ionized gases and high pressures occur in and above the arcing chambers of the molded case circuit breaker.

Safety clearances are required to:

The following safety clearances apply to 3VA molded case circuit breakers:

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Molded case circuit breaker without accessories or with short terminal cover

Molded case circuit breaker with accessories, e.g. phase barrier or long terminal cover

A

Minimum clearance between molded case circuit breaker and current paths (uninsulated and grounded metal), see tables below

B

Minimum clearance between molded case circuit breaker and side walls left / right (uninsulated and grounded metal), see tables below

C

Minimum clearance between two horizontally installed molded case circuit breakers, see tables below;
applicable to fixed-mounted and plug-in versions (see chapter Plug-in and draw-out technology)

D

Minimum clearance between molded case circuit breaker and control cabinet door

E

Minimum clearance between live parts of connection system and grounded mounting plate

Minimum clearance for 3VA1 molded case circuit breakers:

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1)

Can be used for connection methods: box terminal, screw-type terminal, internal circular conductor terminal, and rear terminals

2)

Can be used for connection methods: circular conductor terminal large, front connection bars extended, and front connection bars broadened

Minimum clearance for 3VA2 molded case circuit breakers:

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1)

Can be used for connection methods: box terminal, screw-type terminal, internal circular conductor terminal, and rear terminals

2)

Can be used for connection methods: circular conductor terminal large, front connection bars extended, and front connection bars broadened

O. r.

On request

NOTE

In addition to the clearances stated above, any insulating equipment that might be required must also be considered, see chapter Insulating equipment.

It must be ensured that the cable or busbar connection does not reduce the air insulation clearance.

Accessory components can increase the width or height of the molded case circuit breaker. In this case the minimum clearances apply from the corresponding sides of the overall molded case circuit breaker/accessory combination.

NOTICE

Damage to the molded case circuit breaker and the system

Depending on the application, larger minimum clearances may be necessary.

Please observe the specifications regarding air and creepage distances in the applicable overriding guidelines (e.g. IEC 61439).

Safety clearances between molded case circuit breakers

No minimum clearance needs to be observed between the molded case circuit breakers on the longitudinal sides (see table above).

The following safety clearances apply to molded case circuit breakers installed directly on top of each other:

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x

See tables below for minimum clearance

Front connection with cable, direct

Front connection with cable lug

Front connection with flat busbar

Rear connection with plug-in base or busbar terminals

Insulation of cable

Insulation of busbar

Minimum clearance for 3VA1 molded case circuit breakers:

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Minimum clearance for 3VA2 molded case circuit breakers:

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