No earth connectivity on lights

[opps]

Hi all.

I have just fitted two lights for my mum in her dining room. Previously, there were two lights (front and back, she wanted them to left to right, ie 90 degrees to where the old lights had been)

I tested the voltage between the perm live and earth

It is showing 15v on my cheap multimeter.

The easiest way of getting a new earth to the ground floor lights might be to take an earth from a (ring) socket upstairs (but that means lifting carpet and floorboards).

Is that frowned upon? Don't all earth cables reside on the same connector bar in the CU?

Alternatively, I can run an earth up from the CU and cut holes in the ceiling and run it to one of the earth cables on one of the two lights- in the hope that both lights will now be properly earthed (which should be the case given that the are earthed in the 2 gang metal light switch).

The house is a small victorian terraced property. A room at the front, a room at the back, and then an extension.

I tested the light at the front of the house, in the lounge (admittedly via the switch) and saw 240v between live/SW live and earth. As an alternative, I can drop the light in the front room and see if someone disconnected an earth there (that should run in to another radial).

I am asking for advice, I don't need snarky remarks, but I do appreciate constructive advice.

Thanks in advance

 

[Murdochcat]

Why do you think you need a new earth?

 

[terryplumb]

Wouldn't it be worth establishing where the existing cpc is disconnected ?

 

[flameport]

Find where the break in the existing earth is - very likely at a previous light or switch.

 

[opps]

Why do you think you need a new earth?

Because I am only getting 15v between perm live and the earth cables, whereas I get 240v between perm live and neutral.

In the lounge, measuring at the light switch, I get 240v between earth and perm live.

 

[opps]

Wouldn't it be worth establishing where the existing cpc is disconnected ?

One of the old ceiling roses had two earths, the other had 3. There is continuity between the two lights.

I did consider removing the light in the lounge. I fitted that a few years ago and at the time, didn't see anything wrong with the earths at the time

I don't want to start pulling up carpets.

I figured that a new earth would be the path of least resistance.

It is the kind of house, where, previously, people snipped away the earths rather than running them in to the roses.

 

[terryplumb]

Checking all the cpc's connections at every light fitting may well uncover where the disconnection is.

 

[opps]

Find where the break in the existing earth is - very likely at a previous light or switch.

Thanks for the reply.

Why would a break at the switch have any impact on the earth in the rose.

I agree that the problem probably lies with a previous rose. I suspect that it may be the light in the cupboard under the stairs. The light fitting is between the earthed lounge (read: front room) and the rear room. However, it only has two twin and earths running in to the rose .

I suspect that someone has buried the fittings in the cavity and run a single t&e down to the rose (along with the switch T&E).

Moving towards the back of the house the next rose had 3 T&Es (including one switch T&E), the next rose after that has the same amount, and leads on to the the extension.

 

[opps]

By way of an update.

I purchased a roll of 1.5mm earth cable and have run it back to the CU from the MF light fitting.

My mum wanted a socket in the area under the stairs (where the CU is) so that she could charge her Dyson vacuum cleaner. I figured that If I have to run 2.5mm T&E from the CU, I could run the earth cables through the same channels.

The lights are now showing 240v between earth and live. Hurrrah.

I found a 16Amp MCB in the CU that wasn't being used and decided to use that for the Dyson socket. The CU is split load. The electrician that installed it found faults on the upper and lower rings and put them on the non-RCD side.

I noted that the neutral for the RCD went in to the other neutral connector bar, so I connected my neutral to the left hand bar. I turned on the main power and the RCD tripped. I then realised that the other neutrals on the bar were ones covered by the RCB, I then moved the neutral and everything was fine.

Shouldn't the neutral RCD be on the RCB side?

 

[Taylortwocities]

I found a 16Amp MCB in the CU that wasn't being used and decided to use that for the Dyson socket.

Umm. Well strictly speaking you have created a new circuit, and that is notifiable work under building regulations.

I noted that the neutral for the RCD went in to the other neutral connector bar, so I connected my neutral to the left hand bar. I turned on the main power and the RCD tripped. I then realised that the other neutrals on the bar were ones covered by the RCB, I then moved the neutral and everything was fine.

Shouldn't the neutral RCD be on the RCB side?

Not sure I understand. What is it that you call an RCB?

But even so, it looks like your new circuit is not protected by an RCD? All new socket circuits must be RCD-protected.

 

[opps]

Umm. Well strictly speaking you have created a new circuit, and that is notifiable work under building regulations.

Not sure I understand. What is it that you call an RCB?

But even so, it looks like your new circuit is not protected by an RCD? All new socket circuits must be RCD-protected.

Good points.

BTW, RCB was a typo, it should have been RCD.

I wasn't overly worried about it not being RCD protected given that the Dyson charger doesn't have an earth but, yeah I would rather that it was on the RCD side just incase someone manages to drill through the 2m T&E.

I will order a new busbar and move the MCB



Apropos the neutral for the RCD- if you look at the image the neutrals covered by the RCD, they terminate in 13-N2, but the neutral for the RCD runs into N1. Is that normal?

 

[Taylortwocities]

I wasn't overly worried about it not being RCD protected given that the Dyson charger doesn't have an earth but, yeah I would rather that it was on the RCD

Thats not the point. The regulations are, for new work, that sockets must be RCD protected. The just because the charger doesnt need an earth has nothing to do with it. The next user may plug something that does need an earth in to it. Electrical work is there for life, not just for Christmas!

It would have been easier and better if you had just added your new socket as a spur, connected to the RCD-protected circuit 9 which supplies the ring final.
By doing that
1. you aren't creating a new circuit so you dont break the 'law' by not notifying it
2. the socket will be RCD-protected.

Apropos the neutral for the RCD- if you look at the image the neutrals covered by the RCD, they terminate in 13-N2, but the neutral for the RCD runs into N1. Is that normal?

Yes of course!. That neutral IN to the top of the RCD is the supply. N1 is the neutral supply bar, it is fed from the main switch on the right.
The N2 bar is fed from the output (bottom) of the RCD.

 

[old duffer]

Thats not the point. The regulations are, for new work, that sockets must be RCD protected. The just because the charger doesnt need an earth has nothing to do with it. The next user may plug something that does need an earth in to it. Electrical work is there for life, not just for Christmas!

It would have been easier and better if you had just added your new socket as a spur, connected to the RCD-protected circuit 9 which supplies the ring final.
By doing that
1. you aren't creating a new circuit so you dont break the 'law' by not notifying it
2. the socket will be RCD-protected.


Yes of course!. That neutral IN to the top of the RCD is the supply. N1 is the neutral supply bar, it is fed from the main switch on the right.
The N2 bar is fed from the output (bottom) of the RCD.

I will donate £500 to a food bank of your choice if you can provide a link to the court documents where a householder was fined and jailed for failing to notify part p work. I'll give you a 20 year time frame in which to search. If you can't provide that evidence, you pay the same £500 to a food bank of my choosing.
Do you accept the challenge?

 

[Taylortwocities]

I will donate £500 to a food bank of your choice if you can provide a link to the court documents where a householder was fined and jailed for failing to notify part p work. I'll give you a 20 year time frame in which to search. If you can't provide that evidence, you pay the same £500 to a food bank of my choosing.
Do you accept the challenge?

When replying on these forums, isn't it the responsible way to advise the OP the correct way to go about things?
Should i have said, "nah, just bang it in and switch on mate. What could go wrong"???

 

[old duffer]

do you accept the challenge?