Twin&Earth Sandwiched Between Hot Water Pipes

[jcb208]

You may well end up with knocking or creaking pipes now when the heating comes on

 

[JohnW2]

You may well end up with knocking or creaking pipes now when the heating comes on

... or that previous knocking or creaking of pipes when the heating came on no longer happens

Kind Regards, John

 

[PrenticeBoyofDerry]

One of those pictures seems to show some damage/scorching to the sheath of the cable! I came across a very similar situation a couple years back where the CH pipe had melted the sheath and was attacking the insulation. So it is not wise to leave cables like this in place.

 

[JohnW2]

One of those pictures seems to show some damage/scorching to the sheath of the cable! I came across a very similar situation a couple years back where the CH pipe had melted the sheath and was attacking the insulation. So it is not wise to leave cables like this in place.

I personally wouldn't be too comfortable to leave it there. However, having said that, a year or three ago I stumbled across a cable in my house in exactly the same situation as that (trapped between a pair of CH pipes), which had been there for at least 25 years, probable a fair bit more. When I removed the cable and did some tests/autopsy, although the sheath was a bit discoloured, it appeared to have survived the experience remarkably well, and was even still 'normally flexible' around the region that had been trapped.

I suppose it's not all that surprising, providing the cable is not commonly heavily loaded - CH pipes are not (or should not) be appreciably hotter the 'operating temperature' of conductors in PVC cables.

Kind Regards, John

 

[PrenticeBoyofDerry]

I suppose it's not all that surprising, providing the cable is not commonly heavily loaded - CH pipes are not (or should not) be appreciably hotter the 'operating temperature' of conductors in PVC cables.

You would expect on modern day CH systems, the flow to be a max of about 81°C and the return about 71°C, some system where the controls allow the pipes to get a little warmer such as woodburners, that temperature will raise, now remind me what the temperature rating of flat grey T&E is?

 

[JohnW2]

You would expect on modern day CH systems, the flow to be a max of about 81°C and the return about 71°C, some system where the controls allow the pipes to get a little warmer such as woodburners, that temperature will raise, now remind me what the temperature rating of flat grey T&E is?

Not much below the temperatures you mention

To be serious, knowing how large 'safety margins' appear to exist in relation to cable specifications, I would assume that a cable rated at 70 °C can fairly safely tolerate temperatures markedly above that. I'm not advocating overheating cables but merely offering one possible explanation as to why my cables seemed little scathed after two or three decades of being exposed to CH pipe temps!

Kind Regards, John

 

[Tozzy]

Didn't realise there were more replies here. Just came back to check just incase.

I would have moved the pipes apart by hand and slid a flat piece of timber between them to keep them apart.

If that patch of clean copper was where the cable has been pressed against the pipe then the cable was under enough pressure to suffer damage over time.

The cable was lying over that red circle patch visible in the first picture. You may have to zoom in a bit to see it properly

You may well end up with knocking or creaking pipes now when the heating comes on

More like what JohnW2 said: it no longer happens . It's really secure. The wedgies worked a treat.

... or that previous knocking or creaking of pipes when the heating came on no longer happens

I personally think the cable would have been fine the way it was to be honest, but it was the only chance I had to rectify it. Now that the carpet is down, that cable won't ever see the light of day again, or at least not for another 10, or 15+ years so probably was wise to do what I did