RCD Tripping

[summo]

My main RCD is tripping, only when the sockets ring is on, this is regardless of anything being plugged in.

It is the a 80a RCD that sits between the meter and CU. There is a 100a RCD plug MCB and RCBO in the CU but none of these trip.

Sometimes, the RCD trips as soon as you put the power back on, other times after over an hour. I have used the MCBs etc. to work out it the sockets ring.

I have taken the front off each socket and all wire are in, screwed up etc.. I have check the wire into the MCB is tight too.

I will be call in halp tomorrow anyway, just wonder if anyone had any clues?

Not been in the property long and most of the wiring is of different ages. None of it checked properly yet.
Thanks.

 

[ColJack]

do you hear little scurrying feet under the floors at night?
lost a pet rat recently?

seriously though..
is this a recent thing?
has it been going on since you moved in?
has anything been altered recently?

when checking, is everything unplugged and switched off?
a dying fridge or cooker can cause rcd's to trip...

you say it's the 80mA RCD tripping?

and that you have a 100mA rcd in the CU?

someone did a bad design on that then..

 

[summo]

yeah it is the first one tripping, no mice ! etc..

Only additon are 2 sockets into one room, checked them as well. Obviously cant check the junction boxes under the floor so easily.

Yes, just started doing it today, but nothing has been altered with the electrics for 2 months, probably more.

 

[partpdoctor]

hi
a previous poster could be correct with respect to rodent damage.
if i had to guess i would say perhaps a jb lying in a puddle under the floor
eventually i think it will start tripping the rcd irrespective of the mcb been on or not....
hope this helps

 

[ColJack]

sounds reasonable to me... after the rain we've been having..

guess it's time to grab a pry bar, some wellies and a torch..

 

[Taylortwocities]

Did it rain, rather a lot, last night?

Is there and outside socket or other outside electric item you have forgotten to check?

 

[summo]

concrete floor down stairs, with 50cm stone walls, no leaks.

attic wise, no socket wire run this high up. If i cant get proper help tomorrow, i will bypass the first few sockets and try to elimnate the ones i really dont want pull the wood floor up for!

 

[summo]

thanks for all the help.

The outside socket in the shed has a separate RCBO in the CU feeding it, and MCB in water tight box in the shed, before it feeds a socket.

 

[summo]

Solved!!!

In an existing socket, where the wires were folded as they it was pushed it, the wired had split and it was touching metal case, a tiny hole 1/2 mm, was arcing to the case, only spotted it because of the small 3/4mm scorching.

thanks for the help. Shorted the wires so they fit better and dont need to bend through such a tight turn.

Thanks again.

 

[Softus]

Solved!!!

It would have been quicker to Megger it.

Shorted the wires so they fit better

Er, you don't really mean shorted, Shirley?

 

[summo]

correct !! Shortened the wires !!

 

[securespark]

1/2 mm

Wow 0.5mm, that is small!