RCDs tripping at several properties

Midwest · May 23, 2018

telectrix said:
i'd first of all determine if all the affected properties were on the same phase. if so, then a supply fault on that phase would need to get DNO involved.

Wilko beat you to it, calling DNO #7

Could of clicked old, but that would of been childish.

Octopus · May 23, 2018

Russell Dawson said:
but the pro and site owners don't seem able to do that at the moment.

Jack of all trades, master of none probably

Such installations are highly unlikely to employ permanently a decent spark, nor bring one in at additional expense to their "handy man"

Just saying

snowhead · May 23, 2018

I'd be looking at the Neutral (loose) in the 3 phase db , (if it is 3ph), or upstream switch fuse (if any) or meter or DNO head.

johnduffell · May 23, 2018

littlespark said:
Unfortunately, our RCD testers only measure how quickly they trip, not if they trip too quick

That's not true, the 1/2 dI setting ensures that it doesn't trip at all within the timeout of the tester. If tested at 1x dI there's no lower limit on tripping time.

Russell Dawson · May 24, 2018

Problem appears to have been resolved. One of the homes NOT affected has admitted that he has had a problem over the past few days with a socket that has a short. He has repeatedly tried it and reset when tripped. The timings have been checked and match. It still shouldn't happen though, that is, other houses having their RCDs tripping. Very strange. Thanks to all for input.

stevels4 · May 27, 2018

No theories on this then guys?

Wilko · May 27, 2018

Only guess really - but to trip the adjoining installation RCD implies the fault current is seen over there too, implies local earth not working?

johnduffell · May 27, 2018

how about this for a theory, not really 100% convincing, but ... the fault on another phase would pull that phase and the neutral closer together. Even with similar impedances i.e. no loose neutral, on N and that L (call it L1), the N would move away from L2 and L3. I.e. an overvoltage on those phases.
This overvoltage would last until the fault protection kicks in on the faulty circuit, which could be up to 0.4s for a socket circuit.
If that overvoltage causes extra leakage somehow, the RCDs would trip on the other phases.

If it's not TN-C-S then this could all apply to the installation earths instead.

sham · Jun 3, 2018

Russell Dawson said:
Problem appears to have been resolved. One of the homes NOT affected has admitted that he has had a problem over the past few days with a socket that has a short. He has repeatedly tried it and reset when tripped. The timings have been checked and match. It still shouldn't happen though, that is, other houses having their RCDs tripping. Very strange. Thanks to all for input.

Thank you for letting us know, and have to say, I was kind of right.

bigspark17 · Jun 3, 2018

MDJ said:
Static vans do not usually have hook ups, they are hard wired into a supply from a meter in a building around 20-30 mtrs max from the static and the DB in the van is where the trips are, hook ups are for tourers not fixed statics, that said I do not doubt there are statics somewhere connected to a hook up, and as Tel said a lot of supplies to the meters and switches feeding the vans are PME, well around here anyhow.

Dont know how this comment should be aloud to stay on forum, have you ever worked on any static caravans cos ur talking complete bs!!

bigspark17 · Jun 3, 2018

Hi @Russell Dawson

I had a remarkably similar fault/problem last year on a static caravan site & very similar was the cause, can you answer me out of interest are your homes site fed or DNO fed?

RCDs tripping at several properties

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Midwest

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Octopus

snowhead

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johnduffell

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Russell Dawson

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stevels4

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Wilko

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johnduffell

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sham

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bigspark17

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bigspark17

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