well puzzeled!!!

MUTNA · Apr 1, 2011

hi

I have come across a problem with a ring main thats been recently installed in a new kitchen, obviously there are 2 earth legs yet whenever the cpc on one side of the ring (outgoing leg for example) is conected to the earth bar in the unit the rcd trips, however when the other leg (incoming leg) is conected then the rcd wont trip and neither will the function button operate the rcd, its like its frooze! these problems are the case if only one leg is conected at a time and if both are conected then the rcd will either trip or freeze depending on which leg is conected first, the freeze leg first and the rcd stays on, trip leg first and it trips! i have done continuity tests on all legs and all readings are what id expect including the cpc at roughly 1.76 times the r1 and rn reading. insulation resistance is also coming back great than 200 mega ohms.

has anyone please got any idea what this could be as i am totally beat by this!!!!

thanks in advance

Electricalserv · Apr 1, 2011

Faulty appliance plugged in on circuit? Could be a thermostat or something? Try disconnecting all aplliances then energise....

telectrix · Apr 1, 2011

taking 2 obvious possibilities. neutral in wrong bar, or something plugged in, trapped cable , but fooling IR test ( has been known ). ain't got a clue at this stage mate.

Kamikaze · Apr 1, 2011

telectrix said:
taking 2 obvious possibilities. neutral in wrong bar, or something plugged in, trapped cable , but fooling IR test ( has been known ). ain't got a clue at this stage mate.

I have to agree with you. Sounds like one of the wires has got mixed up with another inside the distribution board and has ended up on the wrong bar.

gpz900jim · Apr 2, 2011

try disconnecting all the other circuits associated with that rcd, neutrals as well so that you are starting with a clean side to the cu and then reconnect your problem ring main. if it works ok, then your problem can be somewhere else, that can happen sometimes, faults can come from other circuits, dont ask me why or how.