I bought some lengths of this from eBay a few years ago but never got
around to using it. I now want to connect it, using an RCD of course,
but examining the cable it seems to be just one thin wire wrapped
around a central insulating core. Presumably I then have to join one
end of the cable to live, loop it through the sand bed and return the
other end to neutral -- using the whole thing in a large loop, rather
than the commercial heating cable which can be used in a line, (so
presumably) must have the wire returning inside the cable.

Anyone else used this? Any idea where I can get a waterproof junction
box from?

Thanks,

John

John wrote:
I bought some lengths of this from eBay a few years ago but never got
around to using it. I now want to connect it, using an RCD of course,
but examining the cable it seems to be just one thin wire wrapped
around a central insulating core. Presumably I then have to join one
end of the cable to live, loop it through the sand bed and return the
other end to neutral -- using the whole thing in a large loop, rather
than the commercial heating cable which can be used in a line, (so
presumably) must have the wire returning inside the cable.

Anyone else used this? Any idea where I can get a waterproof junction
box from?

Thanks,

John
You should be able to find waterproof junction boxes at water garden
centres.
Might be worth experimenting first to make sure that the lengths of
cable you have are appropriate for 240 volt direct across the ends.
Maybe put a highish* power light bulb in series to start with.
* ideally as high as the power you hope to develop in the heating cable.
The bulb should be relatively dim if the cable is suitable for mains use.

bob