"Pete Verdon" d wrote in
message ...
I need to pass a mains cable through/over a joist. There is already a
notch carrying a pair of 22mm central heating pipes. There's physically
room for the cable to go through without touching the pipes, but it would
be rather close to them. Is there a minimum distance between T+E cable and
copper heating pipes?

I would hope so, pvc cable is rated at about 70C and the pipe could exceed
that.
That would imply a de-rating of about 100% for the load on the cable.

I would suggest a few inches are required as long as there is somewhere for
the heat leaking from the pipe to go.
I also suggest you lag the pipe while you are there to reduce heat loss.