Obsolete Live Cable In Wall

[Flashkiwi]

Hi folks,

While visiting some fellow kiwi's in their hovel in London they showed me a warm air heating thermostat hanging off the wall, no longer in use but still live. Knowing I am an electrician( commercial mainly) back home, they asked what they should do with it.

It wouldn't meet code in NZ and I am pretty sure it would be removed , but with the construction of the homes there it is quite easy to do. In this house it is plastered in the wall, it's wired in three core and earth, I guess supplied from a light circuit., probably difficult to trace. Is it code in UK to bury a live cable in a wall? Just for my interest , not doing anything about it , rather go surfing in Newquay .

Cheers guys

 

[Andy™]

bets option is to isolate it completely. if its for an old thermostat, then finding its supply should be easy - itll be where the old heating controls are. although all old heating controls would normally be isolated when the new heating is put in

 

[ProDave]

How do you know it's still live? did you test it?

If it was left live then that's poor of whoever removed the blown air heating system.  Typically with those things the thermostat woudl have been connected directly to the blown air heating unit. So you would have to be doing some to remove a blown air heating system and still manage to leave the thermostat wiring live.

If it's dead, and you have tested it to be dead, and are reasonably sure it's origin is unlikely ever to be connected again then just cut the ends off and make good the plaster.

 

[Flashkiwi]

Thanks gents makes sense. I must admit I done have any gear with me in UK to test. I was going by what the guys told me that it was live ... Mind you what does a bloody dentist know...

I was just interested.

Many thanks guys . Kind regards

 

[Lurch]

Mind you what does a bloody dentist know...

Not a lot, but then again neither do any of the other dentist/electrician folk, but they pay their subs so it's OK.

 

[ProDave]

Even a humble neon screwdriver would tell you if it was live or not.

 

[Lurch]

Even a humble neon screwdriver would tell you if it was live or not.

Not exactly. A neon screwdriver would maybe tell if it was live or not, unless it told you the opposite or nothing at all. I think I could give a better indication from here than a neon screwdriver could.

 

[ProDave]

Not exactly. A neon screwdriver would maybe tell if it was live or not, unless it told you the opposite or nothing at all. I think I could give a better indication from here than a neon screwdriver could.

At the moment they have a wire sticking out of the wall assumed to be "live"

Nobody present has a proper tester.

A neon would confirm if it was live. I suggest that as most households have one in a drawer somewhere. Granted it would not 100% confirm it was not live. But NO tester could confirm that. What if it was connected to a timer and only live at certain times of day and when you tested was not one of them?

 

[Andy™]

then you call the DNO and get them to isolate the street. then you can safely assume its dead* and bury it in the wall

* assuming that all solar etc shut down as required and no-one has a backup generator /UPS

 

[ProDave]

Having determined it is dead, connect ALL cores together, including the CPC before burying it. If anyone then finds the other end and connects it, it will trip whatever OCPD they fed it from.

NOT that any electrician would ever connect it because he would have tested it first and found the shorts.

 

[binky]

£10 multi meter from B&Q would do the job, show if it is live, and allow tracing of circuit to old boiler controls if that is what it is/was.

 

[Badger]

1) get test probes or buy some from the wholesalers

2) test end of cable

3) if live find end by boiler old controls

4) if dead chop the f cker off!

5) if live find controls and check for any connected old cables

6 turn of power at fuseboard

7) short cable ends out

8) test other end as need to find connected source

9) disconnect from supply

10) turn on fuseboard and retest to confirm dead and chop off thus endeth the problem wire

or get a comptetant electrician to find this wiring and get this sparks to disconnect and make safe job done