Trace heating

[Part timer]

Does anyone here have experience of self-regulating trace heating cable within domestic settings? Keen to prevent future 'occurrences' if December's conditions are repeated, I've been looking at my options to protect a mixture of 15 and 22mm copper in our eaves. I have found the following 10W/m cable:

does =93Maximum exposure temperature: 85=B0C - intermittent, 65=B0C continuous=94 actually mean? I'm thinking along the lines of don't power it up in free air unattached to a pipe. Am I correct? I notice that the same company sells a connection and end seal kit: this expensive for what it is if I was to install several separate cable runs? Could I just purchase heatshrink etc of appropriate diameters instead. I have read of the need for C type MCBs due to inrush currents, thermostats, etc.

Would anyone care to do a wiki page along the lines of the one on SWA:

you very much.

[Andrew Gabriel]

What's it used for?

Don't think so. I think it means unsuitable for use on pipework which carries water in excess of those temperatures.

Really? That's surprising.

[Tabby]

For that to be an issue you'd need to be up near the max circuit current rating. For a 6A circuit thats 6x240=3D1.5kW, at 10W/m that's

150m of pipe. Sounds unlikely.

At =A36.75 a metre it would in many cases be cheaper to use a clamp on thermostat, transformer and resistance wire. If the pipe configuration happened to be suitable, you could omit the resistance wire and use a

1 or 2 turn transformer.

p://wiki.diyfaq.org.uk/index.php?title=3DTerminating_SWA

NT

[cynic]

p://wiki.diyfaq.org.uk/index.php?title=3DTerminating_SWA

At =A36.75 PER METRE it aint cheap. I would be concerned that it seems to be intended for maintaining hot water pipes hot rather than cold water pipes warm enough to prevent freezing. Most trace heating suppliers offer two versions of self regulating tape to cater for the two different requirements. Google Raychem and follow their links.

[Tim Lamb]

In message , Part timer writes

You can buy soil warming cable for seed germination/plant propagation etc. Controlled by a frost thermostat, I wonder if this could be adapted for your purpose.

regards

[cynic]

C

ttp://wiki.diyfaq.org.uk/index.php?title=3DTerminating_SWA

The old two wires with heating wire between them has been superceded with two wires with a semiconductor type material between them. The "blurb" says this stuff has a non-linear resistance, rapidly increasing at the design temperature so as to be self limiting. A frost stat to prevent low current usage through the whole year is required for the frost protection version

[Part timer]

Thanks for your replies. Andrew Gabriel: the copper pipes are mains-fed cold water feeding a tank, then the outlets from the tank. I won't be worrying about the max exposure temperatures then. I accept your (an Tabby's) correction about MCB types. I wouldn't be using massive lengths of the stuff. I'm not keen on home-brew methods, hence wanting a reputable product for DIY. Not keen on a lack of water either when pipes freeze, never mind bursts. cynic: the website I linked to says "Designed specifically for frost protection and low temperature maintenance".

FS-A-2X Self-regulating frost protection cable 10W/m at 5=B0C. What's the difference? Tim Lamb: by "unaffordable" what do you mean? I'm prepared to throw =A350+ at my problem this year so I have cold water to feed the hot water system when (not if) the weather turns nasty like it was in December. I've briefly looked at soil warming cables and they cost similar per metre. cynic (2nd post): your explanation is as I understand how they work.

[Tim Lamb]

In message , Part timer writes

My problem is isolated standpipes as well as plastic pipe runs through agricultural buildings. Consequential damage is not the issue for me. Just the inconvenience of no water. I knew roughly the cost of self regulating cable but assumed that a fixed length of under soil would be cheaper.

I'll look again later.