Consumer Unit, long meter tails, best plan of action

[kkkkk]

A Happy New Year to all!!
:clap: :clap: :clap:
:82: :82: :82: :82:

I have been asked what is the best thing to do in this situation: in a house there is a Consumer Unit a long way from the incoming supply. I believe the "tails" are 10mm cable, and go about 7-10m to reach the consumer unit. This is historic, the person now wants to rectify the situation. I suggest the easiest way is to put in 25mm tails of 2m length, to an overload protection device/switch fuse of 100A, then have the remainder of the run as the submain. I am not sure how to assess what size cable the submain should be. Any advise appreciated, especially as it is hard to find specifics on this particular problem.

THANKS!!!!

 

[telectrix]

if you fit a 80A or 60A switch fuse, you can use 16mm tails to the CU.

 

[HandySparks]

You really need to start by assessing the likely load. What is the rating of the existing final circuits and what sort of loads are they supplying?

Once you have this, you can sort out a suitable cable for your submain, possibly with some spare capacity for additional final circuits.

 

[kkkkk]

Thanks to Telectrix and Handysparks.
I can't assess the likely load, it is only advice that the chappie wants at the moment, and my info is limited - I would assume that it is no more of a load than an average 2 bedroom house, with only one occupant. The wiring is historic, I think he is after some grant work, so wants to make sure his wiring won't be condemned by the electrician. I will suggest to him the 25mm tails at 2m, then the switch fuse (is anything between 60 and 100A okay?) Then 16mm cable the rest of the way, which I will assume is 8m, to the CU.
Does this sound acceptable to your more experienced selves?
THANKS again!!

 

[kingeri]

If the main DNO cutout fuse is 100a, then I'd advise using an 80a fuse in your switch, if the DNO fuse is 80a, use a 60a. This allows for discrimination. But don't do anything until you've had a good look at the installation and taken into account the max load.

It's certainly not good to have the main cutout fuse protecting tails any longer than 3m.....if the DNO find out they'll send in a SWAT team. Not.

 

[kkkkk]

I'll warn him about the swat team!!!
That's very helpful advice - thanks kingeri.

 

[Engineer54]

If the main DNO cutout fuse is 100a, then I'd advise using an 80a fuse in your switch, if the DNO fuse is 80a, use a 60a. This allows for discrimination. But don't do anything until you've had a good look at the installation and taken into account the max load.

It's certainly not good to have the main cutout fuse protecting tails any longer than 3m.....if the DNO find out they'll send in a SWAT team. Not.

There are some here that insist, .... The DNO, NICEIC, ELSCA, only require an isolator to be fitted on extended meter tails!! Now what an isolator is going to achieve, i don't know

Rather them than me!! lol!!

 

[chrish_1977]

You could do an eicr then you can give him a pretty good picture of the condition of the installation and also costs involved, nothing worse than starting and finding its needs rewiring