"Sparks" wrote in message
.. .

"Peter Parry" wrote in message
...
On Tue, 16 Dec 2003 20:29:09 -0000, "Will Dean"
wrote:

"Peter Parry" wrote in message
.. .

Can you propose a mechanism for this? The only one which comes to mind
would be that you already had a neutral-earth leakage fault, and the
rise
in
neutral current caused by the bulb-failure arc was sufficient to create
a
leak to earth.

You don't need resistive leakage to trip an RCD and the problems of
pre-sensitisation are become more acute as more equipment includes
noise filters.

I dont know enough about this to comment, only that as I have said before,
in my installation (With incadecent, CFL and LV switchmodes) I have never
had
the RCD trip on a bulb failure (Including with 500w halogens) - So in my
setup
I really dont see the added risk. please explain why in my setup it
wouldnt
be...


TBH, if you know of a property that has an RCD which trips when light
bulbs
blow, then you ought to advice the occupants to get the wiring fixed.

What's to fix? I can set up a demonstration to prove an RCD will
trip on a bulb blowing on a perfectly serviceable circuit with ease.
The point is that an RCD on a lighting circuit does no good at all

Sorry but I totally disagree with that statment.
It will stop people getting killed by electrocution.

but potentially may be very harmful, a situation recognised in the
wiring regulations. What's the agrement for fitting them?

Please explain, in a property where there are never any nucence tips, whay
is it bad?


I'm quite prepared to be shot down in flames
BUT
I operate a wet area supplied via 30ma RCDs
...it has 3kw of halogen lighting - failure mode is
water spray on tubes.
it also has two water pumps
many switchmodes
many fractional HP motors
a large compressor
many incandescents
several EMI filters
many 240v 3 port valves which are damp
and the only RCD trip we ever had was from
a cable rupture in a pudle of water.
MCBs pop often with incandescant failure
but never the RCD
(it's NICIEC tested regularly)