Earthing to Downlights

[Djw360]

Hey Guys after some advice ,

ive had a client who has had her lights changed from low volts(12v) to mains(230v) and has found that the transformer cable has been cut and stripped being a 2 core cable and wired into the new GU10 Lights

she has asked me to wire them to have an earth as stated on the manufacturers box of the new light it requires an earth

do i have to change the 2 core cable

or can you have an earth fly lead from the jb to the light as i see many times single insulated earths on cheap downlights to wire your lighting earth into i know your probably thinking don't be lazy and change the cable but there is like 70 lights to do out of good will so want to keep time down

and bonding to gas and water is single insulated anyways

any help thanks in advanced

 

[Gavin John Hyde]

If you are going to run a single from the db to the first light, why not just run a twin and earth to the light then run new cable between lights, if running a single, you may aswell do it properly and think ahead,
there is also the issue of protection to a single cable running through the building, A large CSA earth for bonding is one thing but as a CPC for a light circuit is a different thing. Not sure off top of my head this time of night about the regs numbers but my instinct would be to do it properly.

 

[Djw360]

If you are going to run a single from the db to the first light, why not just run a twin and earth to the light then run new cable between lights, if running a single, you may aswell do it properly and think ahead,
there is also the issue of protection to a single cable running through the building, A large CSA earth for bonding is one thing but as a CPC for a light circuit is a different thing. Not sure off top of my head this time of night about the regs numbers but my instinct would be to do it properly.

Not from the db just from the jb as there is t+e in and out and some with 3 plate in them it was just a case of does it comply running a single from the JB to the light to save re terminating 70 JBs

 

[Toneyz]

Are you saying you have j.b. at each downlight T&E in and out with a two core flex from each j.b.?

 

[Des 56]

You can run a separate cpc,I believe however it needs to be a minimum of 4mm

 

[Djw360]

Are you saying you have j.b. at each downlight T&E in and out with a two core flex from each j.b.?

Yes Anthony Exactly That

 

[Strima]

Off the top of my head a separate CPC would have to be 4mm. If possible I would run a new T&E.

 

[Djw360]

You can run a separate cpc,I believe however it needs to be a minimum of 4mm

From the JB to the light 4.0mm earth fly lead?

 

[Djw360]

Off the top of my head a separate CPC would have to be 4mm. If possible I would run a new T&E.

Ok thanks

 

[Octopus]

70 junction boxes?

 

[Djw360]

70 junction boxes?

yh in total above each downlighter in different rooms haha sorry my wording could be improved

 

[Richard Burns]

From the JB to the light 4.0mm earth fly lead?

If you have a copper wire protective conductor that is not part of a cable and not mechanically protected the minimum csa is 4mm².
You could run another 2 core flex and then it would be part of a cable!

I think the job will not be worth the headtorch batteries!

 

[Des 56]

I think the job will not be worth the headtorch batteries!

Ah but the head torch battery costs could be more than offset by the sale of 70 transformers

 

[Risteard]

You can run a separate cpc,I believe however it needs to be a minimum of 4mm

Indeed it does unless mechanically protected.

 

[Deleted member 26818]

Use double insulated single core cable.

 

[Risteard]

Use double insulated single core cable.

Aside from the fact that cable can't be double insulated, I have never come across insulated and sheathed green and yellow singles cable.

 

[telectrix]

you can get brown or blue single sheathed. just sleeve at the ends with gn/y. then 1.0mm or 1.5mm will do.sssssimpplesss.

 

[Risteard]

you can get brown or blue single sheathed. just sleeve at the ends with gn/y. then 1.0mm or 1.5mm will do.sssssimpplesss.

You're not allowed to oversleeve green/yellow singles.

 

[telectrix]

You're not allowed to oversleeve green/yellow singles.

read my post.i suggested over sleeving brown or blue.. could even use some left over red or black. seeeing as how blacl is now used as E. sleeved gn/y. when using 3 core brown, black grey.

 

[Toneyz]

You're not allowed to oversleeve an earth/CPC conductor and use as live/neutral but it is acceptable to do the opposite as Tel posted to do the opposite, the only comment that I would make to Tels suggestion is if you are going to take the trouble to add another flex you might as well just change the flex to three core and be done with it or add a 4mm earth depending on termination constraints.