Simon wrote:
I will shortly be replacing a central heating controller clock. The entire
house is covered by a single RCD at the consumer unit, so I guess good
practice is to shut down the entire house rather than rely on the single
pole MCB feeding the clock, and try not to touch neutral to anything
earthed. What would a professional electrician do in this case?

I plan to do this job in daylight, as the lighting will either be off from
the start (if I switch off the entire house) or may go off suddenly (if I
only switch off the MCB and get careless with the wires). How would a proper
electrician handle this situation? Do they carry powerful torches for use in
the winter months? Is limiting myself to daylight hours the sign of a
ill-prepared bogder?

Thanks


Well, the central heating should either have a 13A plug or be connected
to a Fused Spur. If it's a plug, unplug it.

If the fused spur has got double pole switching, turn it off and tape it
off with some insulating tape whilst you rewire the timer.

If the fused spur does not have double pole switching, change it for one
that does, then turn it off and tape it off with some insulating tape
whilst you rewire the timer.

A pro would turn the fused spur off and then grumble when the RCD
tripped. He would then remove the neutral wire from the input side of
the spur and tape it up whilst he rewired the timer.