Board upgrades remote to main CU

[Jimmy Boy]

Apologies if this has been asked before but I can't quite put my finger on the answer searching threads.

1) If you changing a CU that isn't the main CU but a downstream one ie garage, you fill in all the data on the cert. as per normal but Ze and PFC at the origin is that actually where the suppliers fuse is or the new CU supply end ?

2) When your filling the cert. it asks for 'Characteristics' of Primary overcurrent devices if you were feeding the remote CU with a switch fuse would the Primary be the fuse/cb in your switch gear or the suppliers fuse ?

3) If for example you were modifying a circuit to fit a Fused connection unit the Minor works cert asks for a Max Zs on the modified circuit is the value you put in this box the value of the primary protective CB (say a 16 B ) or the value of a 13 Amp fuse in the connection unit ? As I can't find a value for a plug top fuse in the OSG.

Thanks for looking
ATB Steve

 

[pushrod]

Apologies if this has been asked before but I can't quite put my finger on the answer searching threads.

1) If you changing a CU that isn't the main CU but a downstream one ie garage, you fill in all the data on the cert. as per normal but Ze and PFC at the origin is that actually where the suppliers fuse is or the new CU supply end ?
Where the main fuse is.

2) When your filling the cert. it asks for 'Characteristics' of Primary overcurrent devices if you were feeding the remote CU with a switch fuse would the Primary be the fuse/cb in your switch gear or the suppliers fuse ?
The value of your new fuse.

3) If for example you were modifying a circuit to fit a Fused connection unit the Minor works cert asks for a Max Zs on the modified circuit is the value you put in this box the value of the primary protective CB (say a 16 B ) or the value of a 13 Amp fuse in the connection unit ? As I can't find a value for a plug top fuse in the OSG.
The value is the Zs reading that you get at the end of your spur, which for a 13A fuse is a max of 2.42 ohms (brb page 48)
Thanks for looking
ATB Steve

My answers in red - not sure if you are looking at BS7671 certs or a scheme's.

 

[Jimmy Boy]

Many thanks I was looking at an NIC Domestic installer cert but I guess the same info stands

Cheers