Thread: RCD Trips

Originally Posted by arjay

Hi all,
have lurked for a while in many area of this forum, is great!

Anyway I have a problem where my RCD trips(sometimes) when there is a power outage. The RCD is on a sub board in the house, the main board is on the garage and it has no problems.

I reset it and no more problems till the power goes off again.

Any ideas?

yeah, i think there may not actually be anything wrong with the rcd at all. I've come across types, and expect that it is as such, where the rcd has an internal relay that closes when the rcd is reset and opens when the power trips. however, because of the construction of the relay [it's probably got mechanical/push button closure only] it is impossible for the relay to reset itself after a power failure.

The ones of this type that I have come across are inline rcds for use on extension leads. when ever you put the lead in a socket you need to reset the rcd as well.

so, the rcd isn't actually faulty [unless you just absolutely cannot live with an rcd that operates like this- then it may be easy enough for a sparky to replace] and all i'd recommend is that you don't have anything that cannot go without power a an extended period of time [fridges, freezers, grandma's life support] connected to the circuit.

however, this is just speculation based on what you told me and may be wrong.

okay, update. Since I am worried about the power going off and fridge therefore going off and spoiling everything in it, if we are away a little while, thought I'd do some tests. Wanted to know what other points were on the same circuit.

The fridge which happens to be near the inside switchboard needs 2 circuit breakers to be tripped to turn it off!!!!! Yes I said two!! This is a 2yo home, what #$%^ ^@&*( registered sparkie wired this one???

So you can leave either CB on and the fridge stays on?

What does is say under the two CB's in question?

Sounds very strange.

call energysafe victoria, explain the situation. the sparky who wired the house will be obligated to come and repair the circuit free of charge if he wishes to keep his licence.

yes vernon I can have either CB on and the fridge stays on!!!!!!!!!!!!! ie only time there is no power at the outlet is when both CBs are tripped.

At best this sounds like a house fire waiting to happen as you probably don't have proper protection from overloads or short circuits.

At worst you may be at risk of a fatal shock.

I would get this checked at once even if it means paying another electrician to do so. Better to spend a few $ than watch the house burn down - or worse.

I would get it fixed literally tomorrow due to the potentially serious safety risk. In the meantime, I would avoid the use of any heavy power using appliance - heaters etc. Better to be a bit cold rather than burnt or dead.

I am a licensed electrician (Electrical Technician) and this sounds like very dodgy work to me. Certainly not right and quite possibly highly dangerous - you may have been lucky so far but luck runs out sooner or later. Get it fixed ASAP.

yes, dangerous situation turn one circuit breaker off so that the cable is protected against overload until you can get it fixed

Originally Posted by dan76

yes, dangerous situation turn one circuit breaker off so that the cable is protected against overload until you can get it fixed

Very true.

Circuit breakers wired in parallel!! That is a new one

Originally Posted by AV Elec

Very true.

Circuit breakers wired in parallel!! That is a new one

What I'm worried about is what else might be wrong? If someone's managed to put circuit breakers in parallel then I'm not willing to assume that this all they've messed up...

id think the most likely explanation is a loop between two power circuits somewhere in the house and one rcd protecting circuit breakers.
would have been easy to overlook when doing testing if they turned all circuits on and then did polarity, rcd tests etc

yes smurf and dan, where else did they mess up?

still doesnt explain the rcd sometimes tripping when the power goes off in the street does it?

only the one rcd protecting all the power circuits.

arjay, as mentioned before, i think the rcd is not actually faulty. There are types available that must be reset after a power failure.

But, i would still get the electrician back to fix the power circuit fault and report it to energy safe victoria.

i can imagine how this would occur and think that it is a simple mistake to make, but proper testing would have brought it up before power was applied to the house.

Originally Posted by thatirwinfella

arjay, as mentioned before, i think the rcd is not actually faulty. There are types available that must be reset after a power failure.

but why does the rcd trip sometimes the power goes off and not others ? just interested.

I suspect the reason this trips is the interconnection , forcing the rcd's to have out of balance currant,

It needs to be fixed as stated

Doug