Cu in basement and separate cu upstairs ground floor?

NickPynn · Feb 14, 2015

Hello
I am currently rewiring an old house which has tails in basement from meter going into a 60A fused isolator which feeds all the existing circuits from a fusebox in an inconvenient location, to be made redundant.
I need to send power to both a consumer unit in the basement, and a separate CU on the ground floor which will feed circuits at ground level and upstairs level.
DO I:
Treat Ground Floor CU as a sub main, therefore run SWA/ other from Basement to upstairs ? The cable I intend to run above the plasterboard ceiling, poss fixed to the joists
OR
Go from isolator straight to GF CU and send back to basement using that as the 'sub'? The basement may be let to tenants therefore upstairs inhabitants may prefer if possible not to have their CU running off a breaker in the basement.
OR
Feed both CUs independently from the isolator switch/ fix up a 2nd isolator switches?

What is the better option?
Then- can I up the fuse rating in this isolator switch? I'm concerned that the maximum demand may exceed 60A if it was upstream of both CUs.

Anyone got any ideas?

Many thanks,
Nick

[ElectriciansForums.net] Cu in basement and separate cu upstairs ground floor?

Leesparkykent · Feb 14, 2015

Post deleted.

Leesparkykent · Feb 14, 2015

I just looked at your profile and it says trainee. Why doesn't your mentor make the decisions?

NickPynn · Feb 14, 2015

Hi Lee
I'm not self-cert yet, just practical experience and some C&G qualifications in testing & inspecting, 17th edition and Part P. The LABC have been contacted.

Leesparkykent · Feb 14, 2015

So the basement is being split in to a separate property?

Paul.M · Feb 14, 2015

Leesparkykent said:
I just looked at your profile and it says trainee. Why doesn't your mentor make the decisions?

Newly qualified and it is a reasonable question. I've let it ride, play nicely lol.

NickPynn · Feb 14, 2015

No- it's potentially to be used as a granny annexe/ guest floor

Leesparkykent · Feb 14, 2015

Paul.M said:
Newly qualified and it is a reasonable question. I've let it ride, play nicely lol.

Ok no probs I didn't realise the OP was newly qualified.

NickPynn · Feb 14, 2015

Not separate property- basement to be used as granny annexe/ spare guest accommodation.

Andy78 · Feb 14, 2015

Leesparkykent said:
Ok no probs I didn't realise the OP was newly qualified.

Judging by the quals listed on his profile he isn't qualified.

amlu · Feb 15, 2015

one more 60a isolator, link it up to that henley block and use swa for cable run upstairs.
existing one use for a separate consumer unit in the basement.

HandySparks · Feb 15, 2015

NickPynn said:
Hello
I am currently rewiring an old house which has tails in basement from meter going into a 60A fused isolator which feeds all the existing circuits from a fusebox in an inconvenient location, to be made redundant.
I need to send power to both a consumer unit in the basement, and a separate CU on the ground floor which will feed circuits at ground level and upstairs level.
DO I:
Treat Ground Floor CU as a sub main, therefore run SWA/ other from Basement to upstairs ? The cable I intend to run above the plasterboard ceiling, poss fixed to the joists
OR
Go from isolator straight to GF CU and send back to basement using that as the 'sub'? The basement may be let to tenants therefore upstairs inhabitants may prefer if possible not to have their CU running off a breaker in the basement.
OR
Feed both CUs independently from the isolator switch/ fix up a 2nd isolator switches?

What is the better option?
Then- can I up the fuse rating in this isolator switch? I'm concerned that the maximum demand may exceed 60A if it was upstream of both CUs.

Anyone got any ideas?

Many thanks,
Nick

If there's any possibility of the basement being let to tenants, I'd use the existing switch fuse to supply the ground floor board and install a board for the basement run direct off the Henley block (provided it's within 3m).

Dependent on assessment of load, of course.

You then have the option of easily metering the basement supply or putting it on its own DNO supply at a later date.

NickPynn · Feb 15, 2015

Thanks Amlu

NickPynn · Feb 15, 2015

Thanks for that Handysparks!

Engineer54 · Feb 15, 2015

NickPynn said:
Not separate property- basement to be used as granny annexe/ spare guest accommodation.

So what's this then??

The basement may be let to tenants therefore upstairs inhabitants may prefer if possible not to have their CU running off a breaker in the basement.

If this is the case, then the installation will need to accommodate the needs of both tenant and the homeowner. That means provision for a second meter among other things!!

I've a feeling this is your first rewire after a short course at a training center, and it's not as straight forward as you thought!!