RCD Tripping ?

[gselectrical]

Is there continuity between RCD1 neutral bar and RCD 2 neutral bar? J

 

[green-hornet]

Is there continuity between RCD1 neutral bar and RCD 2 neutral bar? J

One of the first tests I did, there was nothing there.

I am starting to feel that there is something wrong with the rcd unit itself.

All tests come out clear, there is no continuity from one bar to the next, and I even tested output from each rcd, everything ok.

I am going there tommoro and I will make notes on what tests I do.

I asked because I have never ever seen this problem before.

 

[batty]

One of the first tests I did, there was nothing there.I am starting to feel that there is something wrong with the rcd unit itself.

All tests come out clear, there is no continuity from one bar to the next, and I even tested output from each rcd, everything ok.

I am going there tommoro and I will make notes on what tests I do.

I asked because I have never ever seen this problem before.

I don't use crabtree but remember reading can't remember where but another sparks had trouble with crabtree gear. Maybe worth changing RCD first and see what happens.

Batty

 

[NozSpark]

If you don't manage to sort it get a photo!!

 

[gselectrical]

Keep us updated! faulty RCD!? J

 

[Theorysparky]

my kettle theory went out of the window once we had all the facts !!!

 

[green-hornet]

Sorry mate it does help if all facts are stated in the original post.

 

[Lee321]

crossed neutral is my guess

 

[Apache]

crossed neutral is my guess

With GH's standard of workmanship?

 

[batty]

crossed neutral is my guess

But it worked to start with so not likely.

 

[PC Electrics]

Just started Batty and its a crabtree

I'm going with it being the RCD. Test them both and see what results you get. if nothing shows up on the 'standard' tests, swap the RCDs round in the board and see if it still trips the same one.

I recently got called to a fairly new house by a regular customer who'd moved. He was having trouble with the Crabtree RCD tripping at random. I tested the RCD 3 times and it showed okay every time. Then it tripped on me despite everything being disconnected. Tested it again and as soon as I did the 50% test it tripped instantly. It was out of warranty so swapped the RCD.

I was curious to the cause, so I opened up the RCD to find it had plastic swarf inside. The edges of the casing showed evidence of machining. Clearly Crabtree were having some problems with the plastic mouldings for the casings and were machining the mating faces, but they weren't cleaning out the swarf properly and it was getting into the mechanism. I was gobsmacked. When I was a Project Manager in the automotive industry, any supplier caught doing that trick would have been flayed alive! I don't trust Crabtree anymore - they've clearly taken their eye off the ball, quality wise. The machining I could live with, but not cleaning out the swarf - it's just so basic!

I'd also had a couple of troublesome Crabtree RCBOs just prior to this too.

 

[Lee321]

But it worked to start with so not likely.

ah missed that.

gh didn't wire it did he and did he say never unconnected and neutrals/earths

 

[Lee321]

I'm going with it being the RCD. Test them both and see what results you get. if nothing shows up on the 'standard' tests, swap the RCDs round in the board and see if it still trips the same one.I recently got called to a fairly new house by a regular customer who'd moved. He was having trouble with the Crabtree RCD tripping at random. I tested the RCD 3 times and it showed okay every time. Then it tripped on me despite everything being disconnected. Tested it again and as soon as I did the 50% test it tripped instantly. It was out of warranty so swapped the RCD.

I was curious to the cause, so I opened up the RCD to find it had plastic swarf inside. The edges of the casing showed evidence of machining. Clearly Crabtree were having some problems with the plastic mouldings for the casings and were machining the mating faces, but they weren't cleaning out the swarf properly and it was getting into the mechanism. I was gobsmacked. When I was a Project Manager in the automotive industry, any supplier caught doing that trick would have been flayed alive! I don't trust Crabtree anymore - they've clearly taken their eye off the ball, quality wise. The machining I could live with, but not cleaning out the swarf - it's just so basic!

I'd also had a couple of troublesome Crabtree RCBOs just prior to this too.

it has to be connected somehow to the circuit that its reportedly not connected to

 

[green-hornet]

Thanks guys for your replies and the problem has now been resolved(but not fixed) :^O

I went back this morning and disconnected all the nuetrals going into the offending RCD.

Then I connected them one by one to identify the offending circuit.

Turned out to be a radial circuit with 2 single sockets and 1 double.

End to end continuity was identical for line and nuetral, and expected results on earth.

Insulation on all tests were over 500, I normally just put 200 on the certs anyway.

Then I tested every nuetral connected back to the open circuit to see if there was any connection from 1 nuetral to the other, none.

I reconnected the circuit and tested again and problem resolved, it did not trip.

Now I hate this kind of "fix", if a problem was found and repaired you can say you have fixed it and sleep at nights. There was no crossover RCD tested fine, circuit showed no signes of any type of fault and I got no continuity to any other circuit.

I now find myself agreeing with PC Electrics, I think it was the RCD, if it does trip again I will just change it, I would think the same problem he described is what has happened here.

Strange one I must admit, but I am now ready for any other RCD showing the same signs.

I did however find an unrelated fault, the cooker hood was a showroom model that they got at a discount, inside I found a block connector which was wired opposite brown/blue, blue/brown.

I assume this is so whilst on show the hood blows rather than sucks so the filters stay clean for resale.

If the RCD does trip again I will give you an update.

 

[Lurch]

I did however find an unrelated fault, the cooker hood was a showroom model that they got at a discount, inside I found a block connector which was wired opposite brown/blue, blue/brown.I assume this is so whilst on show the hood blows rather than sucks so the filters stay clean for resale.

It would make no difference, it would suck on reverse polarity as well.

 

[green-hornet]

It would make no difference, it would suck on reverse polarity as well.

I would have thought reverse polarity, reverse motor!

 

[NozSpark]

I would have thought reverse polarity, reverse motor!

For DC motors YES,,,

but not AC

 

[green-hornet]

I do too many 3 phase

get them wrong and they do run a little akward

 

[Lurch]

I would have thought reverse polarity, reverse motor!

Not on an AC induction motor.

 

[NozSpark]

I do too many 3 phase get them wrong and they do run a little akward

I did a couple of 3 phase compressors a few years ago and making sure that they were going the right direction took a bit of time!