"G&M" wrote
| The Best Practise oft talked about is not to have lighting on a
| 30mA trip duwe to nusisance tripping, many on this group for
| example have advocated no protection for light circuits.
| I stuggle with this. When a light blows here it takes out the
| circuit trip but has never to my knowledge tripped our 30mA RCD.
| Is there something system dependent here ?

The point is not the lighting circuit RCD tripping on a lighting circuit
fault, which is sensible, but a *whole-house* RCD tripping, taking out all
the lights and leaving you in darkness, because of an unrelated fault.

As "dmc" pointed out, and I followed up on 10/7/2003:

| If a whole-house RCD on consumer unit trips on the day that you leave
| for 3 weeks holiday - just as you shut the door. You return to a very
| defrosted rather unpleasant freezer...

The smell should help deter burglars, which is as well as the burglar alarm
battery probably died on the third day.

| Opposite - it trips mid winter while you are away for a bit. Lack of
| heating causes burst pipes and floods the place...

And the video doesn't record all the episodes of Who Wants To Be A Convicted
Fraudster you were looking forward to watching on your return.

Even if the RCD just trips during the night, it takes out the baby-alarm so
you don't hear the wean choking to death during the night, and the
clock-radio dies so you sleep in late. In your rush to phone an ambulance
and your boss, you find the cordless phone won't worth without power to the
base unit, so you rush downstairs, forgetting that the light won't come on
when you press the switch as you simultaneously step off the landing into
space. The noise of you landing at the bottom of the stairs wakes the missus
who starts giving you grief, and after you've dragged your broken leg into
the kitchen you find the electric kettle won't work for the missus' early
morning tea and croissants. After trying a saucepan on the gas, and
giving up on the electric spark ignition, you drag your broken leg through
to the lounge, turn on the gas fire which has crankomatic piezo ignition,
light a newspaper spill, carry that through to the kitchen, and wave it
vaguely at the gas under a saucepan.

Then you drag yourself upstairs again to the missus to explain why there's
no hot water in the en-suite. It's only after taking a
massive-curry-the-night-before dump you realise the saniflo won't flush
either.

Meanwhile, the unlit gas has eventually reached the newspaper spill you
hurriedly threw down in the kitchen, and is no longer unlit. With a gentle
wooomf you now have the next location for BBC Fire Detectives (Tuesdays
10.35pm BBC1) in your very own home.

Upstairs you remain unaware of this, as the weekend you were determined to
fit the smoke detectors Bodgit & Queue were out of stock of the battery
back-up ones so you economised and got the mains-only, and you're busy
trying to pacify the missus and revive the bairn with some warmth. The only
heating you can think of is that old gas bottle heater in the spare room.
Getting the nozzle on in the dark is more difficult than you expected, but
you know it's still got gas in it because you can hear it hissing.

At this point the missus decides that if she can't have an early morning
cuppa, hot bath, or even the telly on to ogle Kilroy, she might as well have
some nicotine and reaches out for the cigarettes and a two-furra-pound gas
lighter.

".... to be continued"

Owain