Electrical Cables on hot plumbing pipes

[john coleman]

Recently had an extension done. Noticed electrician had run mains electrical cables right on to the hot feed from the boiler which gets very hot. Is this a safety issue? Can the insulation stand the heat for hours on end?..

 

[Dave OCD]

I'd say it's very bad practice and should be avoided if at all possible. Is it feasible to fit some insulation to the pipes ?

 

[pirate]

Found similar in my own house...
Sacked electrician, I had to lift a floorboard...cable wrapped round the copper pipe feeding first radiator from the boiler...managed to slide some split insulation over the pipe, separating it from the cable...
believe me, this was a deliberate act of sabotage!

 

[Marvo]

Hours on end will be fine, it's not an immediate safety issue. Most cables are rated to 60 degrees celsius and most domestic hot water systems barely reach this temperature.

Over years or decades the cable insulation will be made brittle by the heat which will be a problem. As mentioned above a short length of insulation on the hot pipe where the cables cross it would be advisable.

 

[pirate]

True, Marvo...but trust me, that copper pipe was already frying the cable...it's a high-output combi and the pipes are far too hot to touch without burning yourself...
No, he intended a failure, and by pure chance the equally crappy joiner had left a floorboard proud, so I lifted it to sort it and that's when i saw his "artistry"...
This wasn't a casual close cable, this was a cable deliberately wrapped spirally round the heating pipe 3 times...

 

[Dave OCD]

Any idea why he did that Pirate ? Had you and him had 'words' previously ?

 

[Marvo]

I've come across PVC cables in contact with steam pipes (115 Celsius) in the past and whilst the insulation had become very brown in colour and completely brittle and crispy over a year or two it hadn't failed or caused an electrical fault. I'd consider it similar to old VIR wiring where the insulation physically degrades but it wouldn't usually cause a fault unless it's disturbed. I don't think it would be an effective way to cause a deliberate fault.

 

[john coleman]

Thanks for the input. My boiler is also a high output Combi and the Pipes feel a lot higher than 60 Degrees..

 

[pirate]

Yes Dave, we had "words" previously. He refused to follow my requests, my diagrams, my written instructions...I came home each night to a mess and had to undo it all and reiterate what I wanted where, and why...
Eventually, I sacked him and placed all the stuff myself.

 

[sparkdog]

Heating engineers seem to have some idea that the cables need to be kept warm.

 

[Strima]

Most PVC cables are designed to operate at a constant 70c.

However most heating systems are set for 75c.

Very bad practice to run together. Sparky needs to come back and rectify. Separation of services and mutual detrimental effect spring to mind.

 

[john coleman]

Yeah, not easily done. In really awkward position behind new Kitchen but your right, I’m not happy with it..and I’m really concerned about Safety risk going forward..

 

[Octopus]

A politely worded email too the spark who did this would be appropriate .. Pointing out the error of their ways ..

 

[Doomed]

There should be no direct contact, but when wiring boilers sometimes close proximity can not be helped.

 

[littlespark]

In a new build extension, there's no excuse for it.

and in response to Pirate, I'm sure a man of your calibre can make safe, cut the cable, unwind from the pipe and reconnect in a suitably placed MF jointbox.