pfc

[soulman]

Hi i am after a bit of advice, I measured pfc at a domestic ccu & got 3.8kA. (PME) Push button breakers 3871 are used for the storage heater board which have a lower breaking capacity that the pfc measured. At the main ccu there were 3036 semi enclosed which are rated around 1 to 2 KA. My question, is this acceptable? I have found in the BGB reg number 434.5.1 which i am assuming this means as long as there is a cutout fuse it's o.k.

Cheers

 

[Richard Burns]

Domestic consumer units are designed to be an assembly that can have up to a 16kA fault current so long as they have a BS88 /BS1361 main fuse.

This is in the (red) OSG 7.2.7 prospective fault current, not sure where it is on the green OSG, just look up fault current.

When the 3036 ones go they will spray metal very nicely, but be safe (ish)!

 

[Chr!s]

Hi i am after a bit of advice, I measured pfc at a domestic ccu & got 3.8kA. (PME) Push button breakers 3871 are used for the storage heater board which have a lower breaking capacity that the pfc measured. At the main ccu there were 3036 semi enclosed which are rated around 1 to 2 KA. My question, is this acceptable? I have found in the BGB reg number 434.5.1 which i am assuming this means as long as there is a cutout fuse it's o.k.

Cheers

No, it's no right, Annex Za won't apply in your case.

 

[soulman]

Cheers Richard, I am not too bothered about the 3036's, i am more concerned with the push in breakers whether they can safely interrupt the fault current.
Can you please explain Chris?

Cheers

 

[alanl]

If you have only 3036's, then it will not comply, as their short circuit capacity is lower then your PFC.
If you have BS1361/BS88 upstream, which have a 16kA/33kA (CBA looking it up) breaking capacity, then it will comply, due to the Reg you quoted (434.5.1).

 

[soulman]

Cheers, for replies i have had it confirmed. Regulation 434.5.1 cover's domestic situation's where fault current is too high for the ocpd as long there is cutout fuse which is normally rated at 33KA (BS 1361 type 2)