RCD keeps on tripping despite all the switches are switched off. Resolves itself after an hour or so.

Forums › Home Workshop DIY › RCD keeps on tripping despite all the switches are switched off. Resolves itself after an hour or so.

turtleattacks

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#311902 25-Feb-2024 09:05

Kia ora,

Our blue RCD keeps have been tripping about twice over the past two weeks. The house itself is about ten years old so the switch would be around that age.

I've isolated it to be the plugs within or kitchen, about three plugs. So as soon as that black power fuse gets switched back on, the RCD would trip again.

However, even though if I've unplugged the appliances from the switches involved and switched off the plugs, the RCD would still trip.

This usually resolves itself after about an hour or two.

I've been told that this is possibly a faulty fuse box/RCD box.

Any suggestions or ideas the cost to replace the box if that's the issue?

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#3199687 25-Feb-2024 09:13

Get an electrician.

Youve done all you can do to be honest and its time for the professionals to come in. Sounds like something could be up with the circuit breaker, the wiring or the sockets in your kitchen (since you have removed all appliances). Maybe something else is hanging off the circuit that you're not aware of. So get an electrician in to diagnose.

tweake

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#3199774 25-Feb-2024 10:59

i would go double check all appliances are off. there is a few that can be hard to unplug. eg fridge, built in microwaves, dishwashers or cooktops, where its really hard to get access to the plugs. a common cause can be fridge defrost heaters.

if thats all unplugged it sparky time. at the moment mice are starting to come into the house, that time of year again. chewed cables or shorted across wires will also do that. nz houses are not air sealed so holes for cables are open to the air and mice crawl in.

snnet

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#3199791 25-Feb-2024 11:03

More often than not it's something outside, usually lights but can be anything

richms

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#3199821 25-Feb-2024 12:29

Its the fridge, defrost element has gone.

Richard rich.ms

turtleattacks

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#3199822 25-Feb-2024 12:30

richms:
Its the fridge, defrost element has gone.

Unfortunately not the fridge (I hate our Samsung fridge).

The fridge is on a different circuit

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richms

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#3199824 25-Feb-2024 12:36

In sink erator is the other thing I have had go that started with tripping, it was random based on how much water had leaked into the motor Remember that any switch is only a single pole one so if it has a fault it will still be causing a neutral to earth fault when off, which will trip when the neutral voltage comes up from other loads being on.

Sparkys are well versed in sorting this out.

Also I don't think that many circuits per RCD was allowable 10 years ago, but someone will chime in with when it became 3 circuits max. Wish we didn't have the BS here that makes RCBOs so expensive vs Australia because this bulk RCD protection across many circuits is stupid with faults like this.

Richard rich.ms

John19612

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#3199843 25-Feb-2024 14:01

richms:

IAlso I don't think that many circuits per RCD was allowable 10 years ago, but someone will chime in with when it became 3 circuits max.

AS/NZS 3000:2007 (Amendment 2). Issued Dec 2012. Cited 31 Dec 2013.

richms:

Wish we didn't have the BS here that makes RCBOs so expensive vs Australia because this bulk RCD protection across many circuits is stupid with faults like this.

What BS are you referring to?

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neb

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#3199862 25-Feb-2024 14:50

turtleattacks:

Slightly off-topic from the original question, but it's really annoying how distribution boards in NZ are labelled "Stove" and "Everything else in the house" ("Lights" and "Power" are often just guesses). Compare this to the standard in other countries:

(that one looks like South Africa, given the labels). If you've got one of these useless-labelled boards, consider going around and identifying which breakers go to which locations, it'll pay for itself the very first time you need to isolate just one circuit.

And you may also find things you weren't expecting, I posted a photo of the Casa de Cowboy board some years ago where there was one area that couldn't be shut down via an MCB because of a wiring loop that fed power in from two locations.

CokemonZ

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#3199912 25-Feb-2024 18:10

I had a similar problem.
Blamed waste disposal and replaced it twice.

Turns out the silicone around my sink had started to fail, and water would leak through, run along under the bench top and drip onto the power socket for the dishwasher.
Sometimes it carried just enough current to trip the rcd.

It took me over a year to get it figured out, and several hundred dollars, and with at least 3, well let's try this attempts.

So yeah, good luck 😉

richms

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#3199919 25-Feb-2024 19:06

John19612:
What BS are you referring to?

Not sure exactly what was required in NZ rcds that Aussie didn't need at the time but my garage ended up with the cheapo method of 3 circuits per rcd because the approx $20 in Aussie rcbos were not acceptable here and the only ones that were were way more and double wide.

If this has changed now I might have to get the tame sparky back to swap over to rcbos.

Richard rich.ms

snnet

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#3199925 25-Feb-2024 19:33

richms:

Not sure exactly what was required in NZ rcds that Aussie didn't need at the time but my garage ended up with the cheapo method of 3 circuits per rcd because the approx $20 in Aussie rcbos were not acceptable here and the only ones that were were way more and double wide.

If this has changed now I might have to get the tame sparky back to swap over to rcbos.

FYI it was never to do with them having to be 2 pole but that the ones accepted in australia (which are now NOT allowed in australia) were type AC which were evidently less expensive to produce (also note there will be a higher demand for anything like this in australia driving the price down there) -- and were not allowed in NZ.

Single pole has been available here all along, just they are usually type A and people don't want to pay for them so the simplest most cost effective solution is a 2P RCCB protecting 3 MCBs. There's nothing wrong with this arrangement -- if you've got stuff tripping all the time there's other issues

snnet

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#3199927 25-Feb-2024 19:40

neb: Slightly off-topic from the original question, but it's really annoying how distribution boards in NZ are labelled "Stove" and "Everything else in the house" ("Lights" and "Power" are often just guesses). Compare this to the standard in other countries:

I always label my boards as specifically as possible :) The ones that come with the board get binned and I use my label maker instead

gregmcc

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#3199928 25-Feb-2024 19:47

Rodent chewing on wiring....

Bung

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#3199933 25-Feb-2024 20:03

If it comes and goes could be ants turning themselves into fusible links in the switches.

Goosey

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#3199953 25-Feb-2024 22:07

richms:

Its the fridge, defrost element has gone.

I was gonna say this !

My mother had the same issue, the sparky came and tested the points and then quickly checked the fridge freezer and promptly informed us to get an appliance tech to look at / replace the defrost unit.

But hey, it could be anything....rodents, moisture in the roofspace, incorrectly wired or damaged or whatever somewhere between the points and the RCD.

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