rcd tripping

[paulrea]

Hi i was wondering if anyone could help me with my cu rcd that keeps tripping,
It is a split board and has a 80a 30ma wylex rcd. It keeps tripping and once tripped does not want to reset until about 15 mins has elapsed.
I removed the 3 mcb's from the live bar and switched th main switch back on but the rcd still would not reset with nothing connected to it.
Does this mean the rcd is faulty? I didnt dissconnect the earths or neutrals from the board just the mcb's.

Any ideas anyone, please because it only stays on for about 30 mins before tripping again! Thanks in anticipation.

 

[rebuke]

A neutral to earth fault can cause an RCD to trip, so just disconnecting the lives doesn't necessarily prove that it is a faulty RCD.

Given you seem happy working in the CU (obviously always switch off, and be careful as tails coming in to main switch will still be live etc), I suggest you disconnect all but one of the circuits live and neutrals (leave the earths connected), and see if it trips. If it doesn't, connect back up the second one, leave it and see if it trips, and if not connect the third. This should hopefully trace which circuit the problem is on (assuming it's a fault on a circuit and not the RCD).

If you figure out which circuit it is, then have a look at all the appliances (particularly wet ones, such as washing machines, dishwashers, showers etc) and check for any obvious leaks. A common one that catches people out is outside lights - if the seal breaks down and water gets in it can cause problems.

If it still trips with all lives + neutrals disconnected then it would probably indicate RCD is faulty, at which point unless you have the relevant test kit I would get an electrician in who can replace it, and perform tests to ensure the replacement is correctly functioning etc...

 

[daz2010]

has this board been fitted long ?

 

[paulrea]

has this board been fitted long ?

I am not sure as have not lived here long, looking at it looks to be approx 5 yrs old

 

[Spark123]

Also try resetting it with the main switch off, if it resets then more likely a fault on a circuit than the RCD itself at fault.