Confused??

[chalkmycue]

Hello

Could you give me a bit of info.
Been looking at a mates consumer unit that he wants changing he has a old reweirable fuse version and is looking to put a more modern version one in, i understand there could be a number of issues with the RCDs tripping on the new board, but there are two areas that i cant get my head round.

He has power running out to his garage via some Mineral cable this is currently run direct from a henley block before it reaches the consumer within the house, once it reaches the garage it enters a consumer unit with RCD protection and feeds a power and a lighting circuit.

He also has a feed from within the houses consumer unit via a 40amp fuse to the loft to a mini consumer unit which again feeds a power and a lighting circuit.

My question is this if the power runs from the henley block to the garage then shorely the only protection for the cable is the 100amp main fuse which doesnt sound right, for the loft it is protected by the 40amp fuse within the board, what is the correct method for routing both of these cables.

I would like to add that i am not doing this work and have advised him to get a qualified Electrican to do the work i am just curious to understand it all better.

Thanks R.

 

[Adam_151]

You are right, there should be some fuseing down (either through a way in the DB or a separate switchfuse) for the submain to the garage

What size is the MICC (it should be engraved on the gland, it'll be something like 6L2 (for 6mm 2 core Light duty) if its metric, or just a three digit number if its imperial

And how is it made off into the henley block, is it glanded into a metal adpatable box, or is it just potted in mid air with the cores going straight in, how is it earthed if thats the case? earth tail pot or BS951 clamp on the sheath

I think we need a picture

Your mate needs to be looking for a commericial/ industrial electrician who can do MICC, and either has the right size tools for the size involved or can work on it with limited tools (look for a NICEIC approved contractor, or ECA approved firm, and mention what you have on the telephone and hopefully they'll have someone suitable