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Selection of MCB for SPD protection

Julien Leblanc
Hello,

I need to install a type 1+2 SPD into the main panel of a small business building, which needs lightning protection.

The main breaker in the main panel is a 4 poles 40A MCB.

I was looking for a SPD and I found this: Schneider A9L16634.

In the technical specification sheet it says "Associated circuit breaker NG125N 80A curve C - Icu 15 kA".

I was wondering why the associated breaker needs to have such a high current (80A)? It seems i cannot ensure the selectivity of the breakers.

Could anyone explain what can happen if i use a smaller breaker, for example a 32A one for the protection of the SPD?


Thank you.




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  • Former Community Member
    0 Former Community Member

    Julien Leblanc:

    Hello,

    I need to install a type 1+2 SPD into the main panel of a small business building, which needs lightning protection.

    The main breaker in the main panel is a 4 poles 40A MCB.

    I was looking for a SPD and I found this: Schneider A9L16634.

    In the technical specification sheet it says "Associated circuit breaker NG125N 80A curve C - Icu 15 kA".

    I was wondering why the associated breaker needs to have such a high current (80A)? It seems i cannot ensure the selectivity of the breakers.

    Could anyone explain what can happen if i use a smaller breaker, for example a 32A one for the protection of the SPD?


    Thank you.




     




    Hi julien, have you considered the A9L15693?

Reply
  • Former Community Member
    0 Former Community Member

    Julien Leblanc:

    Hello,

    I need to install a type 1+2 SPD into the main panel of a small business building, which needs lightning protection.

    The main breaker in the main panel is a 4 poles 40A MCB.

    I was looking for a SPD and I found this: Schneider A9L16634.

    In the technical specification sheet it says "Associated circuit breaker NG125N 80A curve C - Icu 15 kA".

    I was wondering why the associated breaker needs to have such a high current (80A)? It seems i cannot ensure the selectivity of the breakers.

    Could anyone explain what can happen if i use a smaller breaker, for example a 32A one for the protection of the SPD?


    Thank you.




     




    Hi julien, have you considered the A9L15693?

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