MULTIPLE PROPERTY SIMULTANEOUS RCD TRIPPING

[sparkytim]

Interesting call out today to Mobile home park with reports of at least 2 Units tripping out together, all units on site TT with 30 m A RCD main incomers.

Spent a bit of time on one unit but realised problem with Supply, ok for a min or two then lights dip and RCD goes.

Then finds out ALL on same Phase having simultaneous problem

Transient voltage problem me thinks so go in search up the supply

And this was it!

 

[sparkytim]

So proof that yes EXTERNAL FAULTS CAN TRIP RCDs.

 

[bengie]

we had similar in a couple of tenants houses, when one tripped the other tripped aswell, quite odd. we never found the cause as we checked everything internally then called the DNO who sorted it out.

 

[Manator]

Looks like some more remedial work required

 

[sellers]

Transient voltage problem me thinks so go in search up the supply

Could someone elaborate on this for me please.

 

[sparkytim]

Found burnt out nuetral connection just still in contact, giving intermittant disconnection of the supply, this somehow causes imballance to be "seen" by the RCD.

 

[sparkytim]

Looks like some more remedial work required

Yes and I recommended replacement of all of this 3 Years ago, but site owner put it off, had the individual Unit connection points upgraded and sold the site.

 

[kme]

That sounds about typical, mate.

Sellers: there has been previous discussion regarding upstream faults; including transient peaks, interfering with correct operation of RCD`s.

It was suggested from some quarters that an RCD was impervious to upstream interference - Sparky Tim`s post proves that this is not the case.

I could be wrong, but I believe the "upstream issue", as we could call it, only occurs on RCD`s with electronic sensing amplifiers, which is now almost all 30mA devices. I believe the electronics get scrambled by the transient, and trip the RCD; although this is just my opinion.

n.b. 1: Tim - FYI multiple

n.b. 2: forum word of the day: pear cider impervious

KME

 

[bengie]

mmmmmmmm, kopparberg

 

[Sidewinder]

I did start writing a "thesis" on the forum about this, but work got the better of me!

It will take a while before I can continue/finish it, however this thread will give an idea of the sort of problems.

Remember current flows down a voltage gradient...

Paul

 

[sparkytim]

I look forward to reading the further installments.

I have had several experiences similar to this one over the years, and after searching for non existant down stream faults have learnt to look for the signs, Always ask have you noticed lights flickering, dipping? etc.

Overheads often the worst culprit, bad joints up the pole, etc.

 

[SPECIAL LOCATION]

I look forward to reading the further installments.I have had several experiences similar to this one over the years, and after searching for non existant down stream faults have learnt to look for the signs, Always ask have you noticed lights flickering, dipping? etc.

Overheads often the worst culprit, bad joints up the pole, etc.

I had a job with old type ceramic fuse holders..

(got a photo somewhere)

anyway..

bad high Res joint on fuse holders caused RCD to trip...



thats fuses that are upstream to the RCD!