On Mon, 01 Oct 2007 02:49:33 +0100, John Rumm
wrote:


Generally it is fairly uncommon with most brands. However I have seen it
happen with some Proteus MCBs made by Geyer.

The symptoms in that case were that sometimes when you switched them on
mechanically they failed to make any electrical connection. Turning off
then back on again would often fix the problem.

Hello again,

In this case we came home one night and the lights did not come on;
there were no other symtpoms. We looked at the mcb and it was still in
its "on" position, it had not tripped. I changed bulbs, checked
wiring, etc and found no fault so tried another mcb and that worked. I
put the old one back and it didn't, so I know it's the mcb.

It's a crabtree btw.

It's just I thought it would trip to "off" if it failed or take the
rcd with it. No buzz, no smoke, no burning smell, nothing