No Earthing on Lighting

[m4tty]

Hi,

Im wiring an extension atm and was planning to come off the upstairs lighting circuit. I have checked the junction box in the loft and there was 240V L-N but T100 was showing 12V L-E. So i thought maybe no earth. Checked long lead from MET to Earth in JB and confirmed no earth.

In the extension the downstairs lighting circuit (below) has an Earth and wondered if I could run an Earth from the downstairs lighting circuit to upstairs lighting circuit as it would make it much safer plus I could make my addition (test results permitting)

I await being told 'am i serious' lol but am unsure if this is allowed.

Advice appreciated as always

Thanks

Matt

 

[Zeespark]

Why not run a completely new T+E for the extension lights from the CU Matty? that way you are not touching the old installation in any way.

AndyGuinness

 

[batty]

A new circuit will be the best option. I always put them in when I do extensions that way you don't have to get involved with the existing stuff. Just remember if you do join onto existing stuff you have to certify it as safe.

 

[sparkytim]

+1

It is allowed to provide a seperate CPC (MIN SIZE 4mm) but it should run same route as existing L and N.

By the time you have done that then you may as well run new T&E.

 

[m4tty]

Why not run a completely new T+E for the extension lights from the CU Matty? that way you are not touching the old installation in any way.AndyGuinness

Newly done house and dont want to ruin the decor mate. Cheers

 

[Zeespark]

Customer should have called you in before decoratating mate, this is a pet peeve of Mine about this trade. :innocent :run

AndyGuinness

 

[m4tty]

A new circuit will be the best option. I always put them in when I do extensions that way you don't have to get involved with the existing stuff. Just remember if you do join onto existing stuff you have to certify it as safe.

Cheers batty. I wanted to do a new circuit but they didnt want to ruin the newly decorated so thats why ive got to go from existing plus its an easy run.

Am i certifying the whole circuit as safe or just my addition back to the board. If theres bad stuff (which is not picked up when testing the circuit) im not liable for that am I?

Cheers

 

[rugbymacc]

well if you piggy back another cpc from another circuit,

At least your making it safer than you found it.

that's just my opinion for what's it worth....

(ready to be flamed)

 

[Zeespark]

Touch existing circuit = you being responsible for the whole of the circuit mate, even if there are faults on it, you have to fix any defects.

AndyGuinness

 

[Zeespark]

Rugby, what if you have a fault on that part of the circuit in the future? where would you start looking for an answer if there is an unknown shared CPC floating about?

AndyGuinness

 

[m4tty]

+1It is allowed to provide a seperate CPC (MIN SIZE 4mm) but it should run same route as existing L and N.

By the time you have done that then you may as well run new T&E.

Thanks for replying tim. Ive got no option but to go this way mate so if I run a 4mm earth from upstairs lighting circuit jb (which currently has no earthing) to downstairs lighting circuit jb then it would be OK. Will not be able to take the same route as L&N as the circuits are not connected but will run in safe zone if thats ok.

I know its not great but it will be alot safer than it was before.

What do you recon?

Thanks

---------- AUTO MERGE Post added at 21:48 ---------- Previous post was at 21:46 ----------

Touch existing circuit = you being responsible for the whole of the circuit mate, even if there are faults on it, you have to fix any defects.AndyGuinness

Glad im on day rate not price then lol.

When you say even if there are faults on it, your not going to visually inspect every light and jb on the circuit are you mate. There could be twist n taped ones on the circuit hidden and if they dont show up in testing then surely your not responsible for them??

Cheers:C

 

[Zeespark]

You are if they show up as being faulty on your testing Matty. I have walked away from jobs that are like yours because they can be more hassle than they are worth alot of the time.

AndyGuinness

 

[sparkytim]

No sorry m4, although often done it is not deemed acceptable to "borrow" an earth of another Circuit CPC.

How about feeding your new lighting (L,N +CPC) of the DOWNSTAIRS earthed circuit?

As others have said it will mean testing ALL of that circuit and checking it will be adequate for the additional load.

 

[rugbymacc]

Rugby, what if you have a fault on that part of the circuit in the future? where would you start looking for an answer if there is an unknown shared CPC floating about?AndyGuinness

very true ...... (however mattys options are limited here)

what about putting both circuits into 1 mcb with the linked earth?

 

[Zeespark]

I totally appreciate that Matty's options are limited, thinking outside of the box is needed in this case, but you must not leave an install in a more dangerous condition than you found it in.

AndyGuinness

 

[m4tty]

very true ...... (however mattys opions are limited here)what about putting both circuits into 1 mcb with the linked earth?

Cheers for replying mate but i wouldnt put both on same circuit as the whole house on one mcb i dont think would be a good idea. Thanks for trying to help out here tho mate. Appreciated

Running out of options here

Ill check whats on the downstairs lighting circuit and see if it will take the additional load. The upstairs definitely would have but ill check when im back there tomorrow. Cheers Tim

---------- AUTO MERGE Post added at 22:03 ---------- Previous post was at 22:01 ----------

I totally appreciate that Matty's options are limited, thinking outside of the box is needed in this case, but you must not leave an install in a more dangerous condition than you found it in. AndyGuinness

Sharing the earth between the circuits .. is that more dangerous than leaving the circuit with no earth? Your thoughts.

How can sharing the earth be dangerous anyway mate. Im looking to learn here not giving it.

Thanks

 

[Zeespark]

Its more of a pain in the proverbial to sort if there is a problem in the future, not so much a regs issue. If I were you I would bite the bullet and say to the customer that if you want this work to be done, then redecorating would be the order of the day once finished.

AndyGuinness

 

[Apache]

How about feeding your new lighting (L,N +CPC) of the DOWNSTAIRS earthed circuit?

That was my first thought. Many houses have a single 6A lighting circuit. What cable is it? Could you up the breaker to a 10A?

 

[spinlondon]

BS7671 Regulation 543.1.2 allows for two or more circuits to share CPCs.

 

[m4tty]

Thanks for all the replies guys. Much appreciated