Can I add an earth cable to a two core (live and neutral) from another source?

[ericmark]

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.

The wording has changed over the years, but it has been required to run the earth well before 1966 when lighting supplies lost their exemption.

I have often wondered what would happen if one asked an electrician to correct his work 20 odd years after it was done, I would think it would be a case of your suppose to do an EICR every 10 years, so why wait until now?

But it would seem silly for an electrician to take the chance, so question is are you sure there is no earth? There was at one point a move to using alitube cable it did not catch on, two expensive, it was designed so you did not need RCD protection for the cable, this one shows an earth core, but not all of them had an earth core.

Also I didn't want future owners of the property thinking they've isolated the cooker hood from the adjacent switch when it's being supplied from a switch in a cupboard.

It could although unlikely fail an EICR, if the earth does not run with the cable, it would be rather pedantic, but to do it right, you don't really have many options, so personally I would just get a class II cooker hood, and take the one you have back, it is just too much hassle to correct the missing earth. You could clearly get an earth to the hob, a metal splash back could be used as the earth wire, but your still doing something which could be removed without the person removing it realising what they had done.

This was one of the reasons Part P came in, kitchen fitters were at the turn of the century well known for cutting corners, odd but in England the kitchen is no longer a special location, Part P is now a money making law for the scheme providers, it was in real terms a failure.

The problem even if it complies, with running an earth from another supply, is if the supply in the future is no longer required, then it could be disconnected and so you loose the earth.

As long as you have tested the earth, there is really no problem taking it from else where, but the cheapest tester I can find is £64, so is it worth it?

 

[Ragnar_AT]

Is the twin old colours or new? If new I‘d suspect Polish kitchen fitter special, 2-core YDYp is fairly common in Poland. Some countries further east even seem to use red and black twin.

 

[sparkwright]

At the old extractor cable, are you certain the earth wire hasn't been cut out?

 

[plugwash]

I have often wondered what would happen if one asked an electrician to correct his work 20 odd years after it was done

https://www.netlawman.co.uk/ia/time-limits-claims claims that the general limit for breaches of contract is 6 years. The limit for personal injury claims is apparently 3 years from the date of the injury. Fraud calims are 6 years from when the fraud was discovered and that Claims relating to the quality of work in the construction of buildings may be made within 15 years of the fault becoming apparent..

Exactly what category an "electrician being asked to correct their work" would fall into I do not know.