Borrowed Neutral on lighting circuit

[Rikmac]

Hi All
New to this forum.

Im currently doing a Electrical condition report on a domestic house that I have just fitted a dual RCD board and Equipotential bonding in

The Neutral on the landing light is taken from the downstairs circuit so is a C2 on the report
Its not practical to rewire this as the house is for sale and will cause lots of damage

My question is......
If I put both the upstairs & downstairs lighting circuit on one MCB will this comply?
I know two circuts one fuse is bad practice esp on a new board but is it a solution?

Rikmac

 

[IQ Electrical]

Hi All
New to this forum.

Im currently doing a Electrical condition report on a domestic house that I have just fitted a dual RCD board and Equipotential bonding in

The Neutral on the landing light is taken from the downstairs circuit so is a C2 on the report
Its not practical to rewire this as the house is for sale and will cause lots of damage

My question is......
If I put both the upstairs & downstairs lighting circuit on one MCB will this comply?
I know two circuts one fuse is bad practice esp on a new board but is it a solution?

Rikmac

If you take the definition of a circuit from the definitions section of BS7671, technically, the 2 circuits become one.
The disadvantage is that all lighting is lost should the applicable RCD trip.

 

[telectrix]

what IQ said. ^^^^^

 

[Elmer BeFuddled]

What IQ says. I think the separation of up/down or back/front is more good practice than a rule.

 

[Rikmac]

Thanks for your reply
If I leave them on seperate MCB's they are still on the same RCD as both RCD's trip as soon as the light is energised so the solution is to put both circuits into one MCB to obtain a satisfactory result
Ill just put as a C3 that one MCB supplies both up & down lights?

 

[IQ Electrical]

Thanks for your reply
If I leave them on seperate MCB's they are still on the same RCD as both RCD's trip as soon as the light is energised so the solution is to put both circuits into one MCB to obtain a satisfactory result
Ill just put as a C3 that one MCB supplies both up & down lights?

No, if you put both 'circuits' into 1 MCB then there is no code to allocate.
You could make a note on the EICR to say why the circuits were combined and that the client declined remedial work.

 

[Maisie Bolton]

Over the head transmission took place man... Could you be more detailed??? Thanks

 

[Rikmac]

Over the head transmission took place man... Could you be more detailed??? Thanks

Upstairs light on 1 circuit downstairs on another.......if split across 2 rcds both trip when light is turned on due to neutral been taken from upstairs circuit

This is a fail on a EIR as is C2 a defect

Put both circuits on the same MCB (circuit) then its ok

No defect just not good as if the RCD or MCB trip all the lighting will go off

In this case there is a pantry light so the fuse-board will stay lit

hope this clears it up for you

 

[Toonlad]

Why are you doing an EICR,, after you changed the board, and why at time of board change was faults not rectified.

 

[markc123]

Good point, we're all being slow today, but well spotted Toonlad. OP - it should be an EIC not an EICR after a board change.

 

[Guitarist]

What the others said. However, always check for borrowed neutrals BEFORE changing a CU. That way, you can quote for sorting it out before committing to the job. Did you carry out any other pre-change checks or just hope for the best?
Are you doing an EIC or an EICR? They are very different.

 

[MDJ]

Good point, we're all being slow today, but well spotted Toonlad. OP - it should be an EIC not an EICR after a board change.

Yes very good point LMAO, we did miss that, Change a board and do a EICR, oh dear, tonto wheres my horse haha

 

[telectrix]

as the house is being sold, it could be that the buyer's solicitors have asked for an EICR.

 

[gooner85]

Maybe he is doing a EIC for the board change and an EICR for the installation.

 

[MDJ]

but if you change the board then an EICR wouldn't be the right certificate to give would it? it has to be a EIC surely unless things have changed overnight.

 

[MDJ]

Maybe he is doing a EIC for the board change and an EICR for the installation.

Can't see that, if you change the board you have to test the connected circuits as part of the EIC, going to check the regs now, got to go out to the van haha, Tels not wrong, if ever often but in this case I feel an EICR is wrong with a board change.

 

[gooner85]

but how can you give a EIC for the whole installation if you didnt wire it? An EIC for the board change definitely but i wouldnt certify the installation too, just report.

 

[MDJ]

Agreed it's a toughy, but if you connect circuits to a new distribution board then you need to report the readings on the certificate, it is going to be tough to tell the judge if the house burns down it isn't your fault if you connect a damaged circuit to the new board, I do get your point, but just can't agree this time TBH.

 

[telectrix]

agree with you, mike. EIC for the board change. customer may have requested an EICR, in which case do both, as long as you're getting paid to.

 

[Rikmac]

Why are you doing an EICR,, after you changed the board, and why at time of board change was faults not rectified.

Hi its what the customer wanted as a buyer had one done and it failed then buyer pulled out of sale but my customer didnt have a copy of the report......as soon as I saw the job
old wylex board and no equipotential bonding and some other minor problems it turned into an install job so installation cert issued, customer still wanted EICR to show other buyers

Do you start rewiring lighting circuits everytime you do a board change? as most houses that need a board change have a borrowed neutral on hall/landing 2 way
I asked the question for a way of rectifying the fault as installation and EICR are both been done together and without having to rewire