joining two feeds into one consumer unit.

[jouleflow]

I have two 40A swa cables from my main house consumer unit. This consumer unit serves the whole house and the two swa cables serve two consumer units in an extension. One is upstairs and has very little demand and one is downstairs with a higher demand.
My question is:
Can I add the upstairs swa into the downstairs consumer unit allowing more demand and an appropriate t+e cable back to feed the upstairs cu.
Basically I want to join the two feeds together either in the downstairs cu or another way.

This will be done by a qualified sparky but I just want to know if it is feasable before I hire him.

Thanks

Greg

 

[pc1966]

It looks like each phase isolator will also have to isolate the neutral. I guess the neutral could be wired in series over the 3 isolators to isolate it by any switch? I expect that will be too simple.

Each single-phase DB coming off it will need its own independent DP isolator (i.e. the normal main switch).

However, you would be well-advised to have a 4P isolator off the meter(s) tails so you can safely do any work further down-stream without getting the DNO/billing company involved. This sort of thing:

Product - Electrium

Product

www.electrium.co.uk

 

[DPG]

Thanks pc.

The 3 phase supply will now be directly from the grid.
It looks like each phase isolator will also have to isolate the neutral. I guess the neutral could be wired in series over the 3 isolators to isolate it by any switch? I expect that will be too simple.

This is not a recommended solution.

 

[Electro-tech]

I would approach your DNO first to see if it is possible to provide you with 3 Phase, I guess it won't be cheap either. Also, don't forget that the Service Head fuses will be overrated for overcurrent protection of the 40A supplies you intend to protect or connect to.

 

[jouleflow]

Dno booked to install 3 phase.
Can two phases enter an existing 12way split consumer unit with 2 isolators and run some from one phase and some from the other?
Or will I need two consumer units.

 

[DPG]

Dno booked to install 3 phase.
Can two phases enter an existing 12way split consumer unit with 2 isolators and run some from one phase and some from the other?
Or will I need two consumer units.

Have you spoken with an electrician yet?

 

[jouleflow]

Have you spoken with an electrician yet?

Yes, I have discussed various parts of the whole circuit. I'm interested to see if this is possible as it will save a lot of digging of trenches and can utilise the same cables. If I have to buy another cu for a different phase that's ok.

 

[Electro-tech]

I would ask your electrician now as he will be carrying out the work. You can spend a lot of time trying to make it work so why not just make a good job as the DNO will not connect if not happy with the install.

 

[DPG]

Yes, I have discussed various parts of the whole circuit. I'm interested to see if this is possible as it will save a lot of digging of trenches and can utilise the same cables. If I have to buy another cu for a different phase that's ok.

Your electrician would be better buying the equipment. Then he is responsible for. He will also probably not offer any warranty on items you have bought yourself.

 

[jouleflow]

I won't do anything until our meeting at the weekend. Can I assume from the responses that it is not possible to have two independent feeds into one split consumer unit. Or is it against regs.

 

[Electro-tech]

Single Phase small Bang, dual phase bigger bang- 3phase you may be looking at an early cremation.

 

[jouleflow]

Seperate consumer units then.

 

[James]

Or a 3 phase consumer unit

 

[timhoward]

Your electrician would be better buying the equipment. Then he is responsible for. He will also probably not offer any warranty on items you have bought yourself.

He can also likely obtain it considerably cheaper than the OP can.

 

[jouleflow]

Or a 3 phase consumer unit

Good idea, I can just use two phases and somewhere for the third to be terminated.

 

[westward10]

You clearly have no understanding of a triple-pole (three phase) distribution board and the requirements for its supply. It maybe possible to utilise the existing cables but they need to terminated in an appropriate manner and not something you should consider doing yourself it is way beyond your scope of ability. You say you have an electrician so I suggest get them involved to assess what you have and how best to proceed.