RCD Trip

[8181piv]

i have been having a problem with regular random RCD operation found this to be the under floor heating, this has been disconnected with the intenton of reconnecting on seperate RCD supply, circuits fed via split load CU with 80A 30mA RCD, RCD feeds kitchen ring, oven, microwave, garage and utility circuits, main switch suppling all lighting and first floor sockets. RCD has not operated for the last 3 days, but customer has just called to say it has tripped when a lamp blew in the kitchen, now as far as i am aware this should have know bearing on the RCD operation as it is is fed via main switch, can someone advise.​

 

[Des 56]

Is he sure that it was the RCD and not just a lighting MCB ?
Many of the general public dont know that there is a difference and get mixed up about these things

The lamp blowing should have no effect on an upstream RCD as far as I am cocerned

 

[Darkwood]

Gls lamps are a common source of nuisance tripping of mcb's when they blow but for a reason very few people realise, as the filiment breaks down when energised the gap between the filiment pins which once held the white hot filiment becomes ionized which in turn acts like a short circuit thus tripping the mcb, occasionally rcd's can pick up on this but not often so make sure customer does mean the rcd and not an mcb then explain it is sometimes a result of a lamp blowing, as for your under-floor heating is it wise reconnecting it if it has earth leakage you should be explaining to customer that it is unsafe to reconnect, note the rcd was tripping for a reason before you pinpointed it to the underfloor heating.