Earthing New Light Switch

liamus · Post by **liamus** » Sun Sep 12, 2021 3:02 pm

Hi - I have just replaced a plastic dimmer switch with a metal one so needed to earth it. There are three earth wires coming out the wall and screwed in to the metal back box. I assumed that both back box and switch need earthing so removed one from the back box and put it on the switch and left two attached to back box? Is that correct?
Thanks in advance!

Neelix · Post by **Neelix** » Sun Sep 12, 2021 3:30 pm

Not ideal. The earth needs to be continuous so the best way is to add a 4th earth to run from the back box connection to the switch

liamus · Post by **liamus** » Sun Sep 12, 2021 3:33 pm

ah, that makes a lot of sense. Thank you will update it

liamus · Post by **liamus** » Thu Sep 16, 2021 9:46 am

Neelix wrote: ↑Sun Sep 12, 2021 3:30 pm Not ideal. The earth needs to be continuous so the best way is to add a 4th earth to run from the back box connection to the switch

I have some earth wire here but it is multi core - the ones coming out the wall are single core. Does that matter?

I may have the wording wrong - by single core I mean the ones out the wall is a single piece of wire with a loose sheath - the wire I have is stranded when I strip back the insulated cover

Someone-Else · Post by **Someone-Else** » Thu Sep 16, 2021 6:44 pm

What you have is known as multi stranded, what you need is solid core.
Its not so much the fact it is stranded that is the problem, it must be the same size as the existing, which will be 1mm.
Have a look under the floor or in the loft to see if there is an "odd bit" lying there.

liamus · Post by **liamus** » Sat Sep 18, 2021 6:40 am

Someone-Else wrote: ↑Thu Sep 16, 2021 6:44 pm What you have is known as multi stranded, what you need is solid core.
Its not so much the fact it is stranded that is the problem, it must be the same size as the existing, which will be 1mm.
Have a look under the floor or in the loft to see if there is an "odd bit" lying there.

Thank you - I can't find what I am looking for online - all seems to be 1.5mm ? Would you be so kind as to provide a link to what I need to buy?

EDIT - could I but this and cut a length of the earth out?:

https://smile.amazon.co.uk/Core-Round-W ... 81&sr=8-16

Neelix · Post by **Neelix** » Sat Sep 18, 2021 9:08 am

Someone-Else wrote: ↑Thu Sep 16, 2021 6:44 pm What you have is known as multi stranded, what you need is solid core.
Its not so much the fact it is stranded that is the problem, it must be the same size as the existing, which will be 1mm.
Have a look under the floor or in the loft to see if there is an "odd bit" lying there.

Why does he need solid core?

Someone-Else · Post by **Someone-Else** » Sat Sep 18, 2021 9:43 am

Neelix wrote: ↑Sat Sep 18, 2021 9:08 amWhy does he need solid core?

If you read it all, I then went on to say

Someone-Else wrote: ↑Thu Sep 16, 2021 6:44 pmIts not so much the fact it is stranded that is the problem, it must be the same size as the existing, which will be 1mm

Someone-Else · Post by **Someone-Else** » Sat Sep 18, 2021 9:47 am

liamus wrote: ↑Sat Sep 18, 2021 6:40 amEDIT - could I buy this and cut a length of the earth out?:

Yes.

Neelix · Post by **Neelix** » Sat Sep 18, 2021 9:56 am

Someone-Else wrote: ↑Sat Sep 18, 2021 9:43 am
Neelix wrote: ↑Sat Sep 18, 2021 9:08 amWhy does he need solid core?
If you read it all, I then went on to say

Someone-Else wrote: ↑Thu Sep 16, 2021 6:44 pmIts not so much the fact it is stranded that is the problem, it must be the same size as the existing, which will be 1mm

So why complicate matters in the first place?

Someone-Else · Post by **Someone-Else** » Sat Sep 18, 2021 4:00 pm

Neelix wrote: ↑Sat Sep 18, 2021 9:56 amSo why complicate matters in the first place?

I don't know why you choose to complicate matters. The OP is happy.

liamus · Post by **liamus** » Mon Sep 20, 2021 8:47 am

Someone-Else wrote: ↑Sat Sep 18, 2021 9:47 am
liamus wrote: ↑Sat Sep 18, 2021 6:40 amEDIT - could I buy this and cut a length of the earth out?:
Yes.

Thank you