DIY Doctor UK DIY Forums

Hiya guys,first post.
Im buying a house and just waiting for it all to got through hopefully within the next month.
At the moment there is a small 7 way conumer unit in there at the moment.
I want to change this for a 12 way split load board with an additional board feeding the garage supply.I want to split the current circuits also and tidy everthing up.
There is no power to the building at the moment as the place has been vacant for months with the services being cut off.

I dont have a clue which mcb feeds where around so can i fit a 100amp double pole isolator switch between the meter and the consumer unit installed so i can get the power on then switched off when convient to change the board?
So i can split the circuits an do relevent tests also?


Thanks for reading any info appreciated?

I think you will find this is now provided by the supply authority as standard when reconnecting a supply. There is a limit to size of cables that will fit and in the past I have seen 3 phase 160 or 200 amp fused isolators with 80 amp fuses feeding different consumer units incomers all linked, so a supply of more than 100 amp can be provided as most consumer units are limited to 100 amp. But after all that board would only give them 100 amp so all a little pointless. Maybe phone call to supply authority? Remember supply authority not billing agent.

as an electrician i recomend u get an electrician to change your consumer unit if it only has 7 fuses or mcbs then unless the previous electrician has doubled up on your lights or radial circuits you will still only have 7 circuits. the rings cannot be spilt with out rewiring them. hope this helps u. but really unless u know what u are doing its safer to get an electrician

Hi if I understand you correctly then it may be a good idea to get an isolator fitted whilst dead for easy future upgrades, why not get a 100mA / 100A RCD in an enclosure which would give some protection to the non-RCD part of the intended split-load board as well?
regards SPARX
{usual Part-P comments apply}
NB new meters in our area (Kent) do not come with isolating switches inbuilt.

Same here in ******* new meters fitted in whole road NO isolator fitted.

Did see it on the drawing on the online part p document.
If this is part of part P would they be contravening it !!!!

Since when have supply authorities kept to the rules? Although the 16th says they do not have to follow it. There own regulations say they should. And since when does a 16mm² concentric cable have a ratting of 400amp? They do as they want. Here new houses always have isolator but on existing when they re-connect one has to ask but no charge. But of course works other way when not provided they don't seem to get upset when seal on fuse is broken. I did expect them to kick up when I found it had been removed by electrician before me. As to 100ma RCD I have seen many 63Amp RCD's fitted and really if only protected by supply authorizes fuse they should be 100amp rating. MK do a 100amp and so do Proteus but most are only 63 or 80 amp rating as 2 module wide. I have also had problems with building inspectors where 100ma RCD was fitted on a TN-C-S supply. He could not tell me where it said you shouldn't fit so in the end I got away with it, but he didn't like it because of losing lights if it trips. All my house is on two 30ma but I also have emergency lighting too. Both 4 module wide and 100amp.

so should i request the authority when getiing supply reconnected to add an isolator?they should do it free of charge at request.
Also juan this is the reason i want the isolator so i can test to see if any have doubled up etc
thanks for info guys