No earth on lighting circuits

[wesj]

My brother bought his house off the council of the council about 3 years ago and I am giving him a hand with the refurbishments .With regards the electrics we will get an electrician to replace the old rewireable board with split MCB/RCD cosumer unit.We have found that the old red& black T&E to sockets looks in good nick but the steel back boxes were not earthed but we have now done this.With the 2 lighting circuits which are wired in single cables there are no earths at lights or switches.Would it be OK to run single 1.5 earth cable to switches and lights and leave 2 tails by fuse board so that when we get a sparky he can test the earth loops and connect to the consumer unit he will fit?. Thanks in anticipation . Wes

 

[Adam_151]

Is that DI singles? or singles in conduit?

 

[wesj]

Thanks Adam151 they are singles 1.5 red and black in grey outer sleeve but with no earth.

 

[Adam_151]

While you could run a separate CPC side by side (not sure what the mimimum size is when run outside of conduit, something in back of my mind says 4mm², but while that applies to bathroom supp. bonding I'm not sure its the same here, would have to look it up!)

It'd probably be far easier/better to rewire the lighting circuit, remember that the requirement to include a cpc same in with the 14th edition of the regulations which came out in 1966, so your lighting circuit is over 40 years old!

 

[baldelectrician]

http://www.electricalsafetycouncil.org.uk/pdf/BestPracGuideJan07secure.pdf

 

[IJWS15]

Is the cable, especially the singles, rubber or pvc insulated?

 

[wesj]

Thanks IJWS15

I think the inner insulation is a type of plastic rather than rubber, the outer grey certainly is.

 

[JohnD]

I agree with Adam,it will be better, and probably easier, to rewire the lighting system entirely in T&E. You will probably be wanting to renew the switches and roses anyway. Unfortunately you will need to take up some flooring but can probably do a lot of the work from the loft.

Is there any sign of conduit for the drops to the light switches?