On Mon, 9 Aug 2004 14:51:52 +0000 (UTC), "Rick Hughes"
strung together this:

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.

Now I prefer to have some protection to prvent fire hazard, and thus have
all light ccts through a 100mA RCD which are much less prone to nuiscance
tripping.

You've obviously mis-read something somewhere. RCD=earth fault
protection, MCB=overload protection.

RCD's work by measuring the amount of current on the live cables and
ensuring they are equal, if they aren't, by an amount determined by
it's rating, then it assumes the current has gone to earth, either
through a faulty appliance or you, and trips.

A light bulb isn't earthed so wouldn't take out an RCD. You're
thinking of MCB's which protect final circuits, light bulbs can easily
take out type B MCB's as the bulb takes a surge of current as it blows
which overloads the circuit but by fitting a type C or a HRC fuse to
the lighting circuits this nuisance tripping can be reduced.

Type C MCB's and HRC fuses react slower so won't always trip\blow.

If that's what you based the 3 classes of protection on then you might
not be the best person to be doing this project.

My question is really pretty simple - do I protect Imeesrion and cooker or
have them unprotected.
AFAIK the regs do not require protection, but that doen't mean i t's best
practise.

The immersion doesn't require RCD protection. The cooker doesn't
either, unless the manufacturers instructions say so or if the switch
incorporates a socket that can be reasonably expected to supply
portable equipment outdoors.
--

SJW
A.C.S. Ltd