2 lights in same junction box

[ban-all-sheds]

If, as you say, it is only a small portion of the circuit that current doesn't have a CPC, why is it such a large problem to replace the affected wiring?

It's the lights on the stairs/ front bedroom unfortunately, so basically need to go all the way back to the CU.

You'd only need to go all the way back to the CU if none of the circuit has an earth, surely?

If most of it does then it must start at the CU and carry on for most of the way.....

 

[leezer3]

If, as you say, it is only a small portion of the circuit that current doesn't have a CPC, why is it such a large problem to replace the affected wiring?

It's the lights on the stairs/ front bedroom unfortunately, so basically need to go all the way back to the CU.

You'd only need to go all the way back to the CU if none of the circuit has an earth, surely?

If most of it does then it must start at the CU and carry on for most of the way.....

It's over half the circuit, and basically, it'll end up being the better part of 30ft worth of plastering based on the way the cables are routed, and a lot of that on the roof of the stairs.
Some of the cable routing in this house is a little odd; the front and back of the hose are wired on separate circuits, and the cables don't necssarily go where you'd expect- There was an extension added in the 1970s, and I think various bits got done then, followed by more changes in 1995 when the current CU was fitted.