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Fire Alarm Panel & Refuge Alarm Panel: 0.4s or 5s disconnection time?

Apostolos

Good afternoon

A question that may sound silly but there it is...

Do we treat the power supplies to the Fire Alarm Panel and tot he Refuge Alarm Panel as final circuits or as submains?

Are they 0.4s disconnection or 5s disconnection time?

Do these panel have any internal distribution which would make the supplies to them typically 'submains'?

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    Any internal protection wouldn't protect against faults at the incoming terminals (or through the outer casing) and would be outside BS 7671's scope anyway, so I don't think that would help.

    If you had something like a FCU just before the panel, I could see an argument that it could be a distribution circuit up to the FCU, and a final circuit after. Not that it would make much difference if you're using MCBs - since Zs would be the same for both 0.4s and 5s disconnection times (for them it's either magnetic operation and it opens in <0.1s or thermal and takes >>5s) (I presume you won't be using D-types). On fuses, there might be something to argue...

       - Andy.

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