Trouble shooting an RCD protected circuit

[EFLImpudence]

Did the tenant leave under good terms and was he an electrician?

 

[JohnW2]

It's very much a long-shot, but the one other thing you could try would be (with all MCBs off) to switch off the other RCD, and see if you could then reset the tripped one.

I presume you are just 'trying everything'.

Can you think of any approaches other than "try everything", given where we've got to?

There's no way that current on the 'other side' could cause the tripping without also tripping that RCD, is there?

Well, we're scraping barrels! I suppose it's possible that a small N-E leak on one side might not be enough to trip one RCD, but may be the 'last straw' for the other one if there was also an N-E leak on its side, and particularly if the trip thresholds of the two were a little different. However, TBH, I was really just thinking the same as you (Main Switch) and getting everything (double-pole) switched-off - since if the RCD would then still not reset, and the OP has effectively ruled out a faulty RCD (by swapping), we would have an 'almost impossible' mystery on our hands (unless there is something very odd/wrong about the wiring of the CU!).

Kind Regards, John

 

[JohnW2]

Did the tenant leave under good terms and was he an electrician?

I meant to ask at least the first part of that ... but if the answers are No/Yes respectively, I guess that almost anything is possible (and I'd start by having a careful look inside the CU!)

Kind Regards, John

 

[BlackPotato]

They left on very amicable terms and I still hold a sizeable deposit. She contacted me on the day, said she had called her nephew that was an electrician and had tested over the phone what she could.
His comment apparently was its something in the unit.

Strange timing though, a day where lots of things got unplugged, cleaned etc...

 

[Iggifer]

There's no way that current on the 'other side' could cause the tripping without also tripping that RCD, is there?

I have seen a split load board that had a number of small faults on the LHS rcd, none on the RHS, yet turning on a specific light switch fed from the RHS caused the LHS RCD to trip.
No faults on the RHS, and clearing the other faults cleared the behaviour. But it was a repeatable occurrence, i.e. it happened every time you turned the lights on. Very bizarre.

 

[Iggifer]

Strange timing though, a day where lots of things got unplugged, cleaned etc...

I was thinking cleaning. I have had to do some major cleaning when moving out of flats , not because I'm particularly unclean, but landlords eh?

I guess it could be lots of things, water has got into a junction box under the floor, water in a socket.

Do you supply fridge/freezer? Are these still plugged in? If they were defrosted on moving out water could have got somewhere it shouldn't.

 

[JohnW2]

I was thinking cleaning. I have had to do some major cleaning when moving out of flats , not because I'm particularly unclean, but landlords eh? I guess it could be lots of things, water has got into a junction box under the floor, water in a socket.

... unless the OP confirms (which he already thinks is the case) that he can't reset the RCD with the Main switch off ... in which case it becomes a major mystery.

Kind Regards, John

 

[AndyPRK]

Rather than swap rcds, what you usually do is switch off the mcbs on the troublesome side.

Then disconnect the neutrals associated with those circuits from the neutral bar. And try and reset the rcd.

You either disconnect the neutrals one at a time or all of them or suspect circuits or circuits you don't require. Etc.

 

[JohnW2]

Rather than swap rcds, what you usually do is switch off the mcbs on the trouble some side.

The OP has apparently done both (and quite a lot more). As you say, the next thing to do is to start disconnecting neutrals, but that's probably best left until his electrician attends on Wednesday!

Kind Regards, John

 

[sparkwright]

Could they have removed any of their own light fittings before they left?

Could they have hastily replaced any damaged sockets before they left before you noticed?

 

[EFLImpudence]

You neither disconnect the neutrals one at a time or all or suspect circuits or circuits you don't require. Etc.

Would you care to proofread that?

 

[JohnW2]

You neither disconnect the neutrals one at a time or all or suspect circuits or circuits you don't require. Etc.

Would you care to proofread that?

That's a bit rotten for a Friday evening - it only needs to have one "n" removed to make it at least understandable

Kind Regards, John

 

[AndyPRK]

Lol

I will remove the n!

The op has already got quite involved with swapping RCDs ! So he may as well do the easy task of removing some neutral wires.

Just note they need to go back to the same neutral bar.

 

[AndyPRK]

Hi,

I have a 3 bed Terrace property that has been rented and on the day the tenant moved out half of the electrics failed.

Modern fuse box, 2x RCD's each with 6 MCB's

One RCD wont reset & the RCD's have been swapped and the problem isnt with the RCD.

This RCD has;
MCB's for Oven, Hob
Socket circuit (all) that has extractor and boiler hard wired (No "plugged" appliances connected)
Downstairs lighting circuit



Richard

Looking at the picture the problem circuits appear to be:

Sockets
Garage sockets - 6 Amps ??!!
Lights

Is the garage attached?

 

[DaveHerns]

They didn't have a cannabis farm in the loft by any chance?