Another electrical problem

[123hotchef]

Right quick one came home from work to find rcd tripped one side of the cu narrowed it down to the living room ring main now I have tested every socket with a plug in type tester that lights up with 3 lights all good. So should I now remove them all and visually check them or could it be the mcb at fault i don't really see how it could because that just pops when the amps are exeded. Everything has been unplugged and all sockets off and the rcd still shuts down aftet a few seconds.

 

[rtbcomp]

Damp finding its way into a socket or junction box?

 

[rikrobson]

have you access to a clamp meter to measure the actual amps in the circuit?
I'd swap the mcb with the upstaris ring and see if that trips.
then its disconnect and measure resistance point to point

 

[123hotchef]

No pics or holes drilled no. Just been under the house too no damp anywhere. I'll swap the mcb out next before I start pulling every socket off

 

[123hotchef]

have you access to a clamp meter to measure the actual amps in the circuit?
I'd swap the mcb with the upstaris ring and see if that trips.
then its disconnect and measure resistance point to point

I have a cheap clamp Meter would it work measuring the Amps with everything unplugged and all the sockets off

 

[rikrobson]

if there is a short then there will be current. if there is no current then is probably a fault with the mcb, hence the suggestion to swap it out with the other ring.

 

[brightspark]

is it the rcd tripping or the miniature circuit breaker or even both

 

[123hotchef]

Just the rcb tripping mate

 

[rikrobson]

is it mbc or rcd?
mcb is just current and rcd is earth leakage too

 

[WorkshopChris]

If its a rcd tripping swapping mcb's wont help.

 

[brightspark]

are u sure every plug is pulled completely out any fused spurs switched off. how many rooms does it cover

 

[123hotchef]

Yep all plugs are pulled out this circuit is just the one room I re wired it when I made it 1 large room 2 years ago. No fused spurs just a small ring main 16 double sockets around the room

 

[WorkshopChris]

So just to confirm all:-
plugs pulled
no fused connection outlets
all other mcb's on that side off

rdc trips after a few mins.

 

[brightspark]

what u can do is part the ring main at a socket roughly in the middle of the circuit then part one leg of ring at the db. turn back on if its ok its the other leg that's faulty. if it trips put the other leg in and remove the one connected . that will half your problem and narrow it down a bit by half

 

[brightspark]

when u establish which leg is faulty part that in the middle. connect the leg back up in db. if it don't trip the faults in the quarter section that is disconnected if it trips its in the quarter u have just connected

 

[rtbcomp]

is it mbc or rcd?
mcb is just current and rcd is earth leakage too

rcd is earth leakage only

rcbo is current or earth leakage

 

[WorkshopChris]

Just one other thing if you reset the rcd with all the mcb's off does still hold in. To rule out e>n fault.

 

[dobbslc]

You could have a neutral to earth fault on another circuit. The neutrals are still in circuit even with the mcb's turned off, maybe worth trying pulling the other neutrals out and then seeing if the rcd holds.
Have you done an insulation resistance test on that ring?
Are you sure there's not a spur for an outside socket or something else that could be at fault?

 

[brightspark]

parting all the neutrals and with breakers off a simple insulation test would answer your question in 5 minutes flat where the fault lies and which circuit . as said there may be a neutral to earth fault in another circuit

 

[123hotchef]

All the other circuits are working fine I am out at the moment it's just that circuit that trips the rcd. Only have the one bad circuit turned off at the mcb atm. I did install an extra socket a few weeks back I had the wires in the cupboard under the stairs for 2 years before deciding I needed the socket installing. I think I'll check that one when I get back it could have worked a wire loose as I plugged my new sonos system into it.