CPC carrying live current, electrician says it is OK?

I've been following this thread with interest.
Could I have your thoughts on this please.
While at a property a few days ago, the customer asked me if I could change a faulty room thermostat. No problem so I thought.
On changing it, I found that it was fed using 1.5mm T&E and whoever wired it in originally used the CPC as the permanant live and sleeved it yellow. This house is over 100 years old, and has the old colours.
I tried to trace the cable back to some kind of wiring centre or J/box but could find nothing. I couldn't even find where tha cable came out in the roof space, it just disapears into the wall.
Would you insist (like me) on that cable being replaced?

 

I would because its an exposed live conductor. Swap the stat for one that doesn't need a neutral maybe?

 

The sleeve covering the whole wire relies on the electrician cutting it to length accurately and then making sure its tight up against the accessory on the terminal. Plus I've seen itwbere sleeving has been torn by a box tab or wood screw or box screw . fact is that its far too thin to be relied upon to Insulate a live conductor. If its being used for live the chances are that there's no earth. You just don't doit

 

Earth sleeve these days is really thin, cheap and nasty.

 

Yes.

 

Whichever way you look at it, you need make that cable safe. You can't now leave it live knowing about it. Yes install a new cable but you still need make that old cable safe or you might be liable for leaving a dangerous conductor in the property and knowingly.

It is one of them hair pulling situations where it drives you mad but now you know about it you have to act on it.

 

Does it go down the wall. What's the wiring in the boiler like?