Unearthed lighting circuit repair

[Terry641]

Hi, thanks in advance for any advice the community can give me.

I’ve got a lighting circuit which I’ve recently learned is unearthed. Some of the cabling is damaged and needs replacing. Can this be done without a rewire down to the CU to still be compliant with the standards.

It would be really useful to know
what is permitted and what isn’t. Or if there are any other solutions that can be applied to resolve the problem.

Thanks,

Terry

 

[sparkwright]

Yes, you are able to replace damaged sections of cable on existing circuits.

 

[ericmark]

Pre 1966 it was common not to have an earth with lighting, in the main cable that old is rubber, and needs renewing even if it did have an earth wire. However the other reason for no earth is where SELV (separated extra low voltage) lighting was used, and has been converted to standard low voltage (230 volt AC) and often there is an earth where the transformer was, so it just needs a few wires renewing.

I remember trying to run earth wires in a farm house, it was in the Falklands, but that does not matter, I got so far, then found no access to loft area, and it was going to be a big job, so had to abandon it. So learn from my error, and see where you can run wires first.

A circuit protective conductor shall be run to and terminated at each point in wiring and at each accessory except a lampholder having no exposed-conductive-parts and suspended from such a point.

is the basic rule which changed. But we also have

SELV (separated extra-low voltage). An extra-low voltage system which is electrically separated from Earth and from other systems in such a way that a single-fault cannot give rise to the risk of electric shock.

so many 12 volt lighting systems should not have an earth.

 

[bernardgreen]

Can this be done without a rewire down to the CU to still be compliant with the standards.

You will need to connect the Earth conductors of the new cables to the Earth bus bar in the CU or to the MET ( Main Earth Terminal )