Puzzling tripping issue

[gcunit]

Struggling to work this one out. My house downstair's electrics keep tripping:

- only started after old meter was replaced with a smart meter;

- always happens (bar perhaps one time) when the oven is heating up, will be on a minute or two so isn't instant, but it's before it reaches temperature. Might trip 2, 3 or 4 times, then will work afterwards. Sometimes doesn't trip at all (seems worst in the evenings, but tried it at 12:30 today and didn't trip at all);

- don't know how old oven is, but at least 9 years old and was here before we moved in;

- downstairs RCD trips, but the oven has its own fuse and never trips. Sometimes the garage fuse does trip, but I've turned the garage fuse off and the RCD has still tripped when using the oven.

So is this the oven causing this? The wiring? Something else on the circuit? Or is it all linked to the smart meter installation?

Any help/suggestions appreciated. Thank you.

 

[Wilko]

Hi GC - sorry to hear about the tripping. Any chance of a pic of your Consumer Unit ?

 

[Midwest]

My money is on the oven element, but lets wait and see.

 

[Pete999]

My money is on the oven element, but lets wait and see.

yep, good call, oven heating up, expansion and contraction causing a fault

 

[davesparks]

The most likely and obvious answer is that there is a fault with the oven element.

 

[Lucien Nunes]

Agree with both the above suggestions.

Sheathed heating elements can become unsealed and let in atmospheric moisture, which lowers the insulation resistance. When the element heats from cold, moisture that was spread throughout the element condenses at the colder ends, concentrating it and further reducing the insulation to the point where it causes enough leakage to trip the RCD. Once the ends are hot too, the moisture disperses again and the insulation rises.

Or, as per Pete999, damaged wiring or a component in the oven shorts to earth as things move with the thermal expansion of the oven heating.

An insulation test will soon tell the difference between these two possibilities. I suspect the smart-meter installation is a red herring.

 

[radiohead]

Could also be a completely unrelated N-E fault elsewhere on the system. However given that the info from the OP is that it only trips when the oven element is on that is the most likely culprit. I would suggest to the OP not to just assume and buy a new oven without some testing, there's many wasted their money on a new appliance when the issue is a N-E fault elsewhere.

 

[littlespark]

Wasn’t there a few posts about smart meters tripping rcd’s ??? Something to do with the comms
I think wrapping the meter in tin foil was suggested... I could be wrong.

and I had to read your name twice, @gcunit... wondered how it got past the sweary filter

 

[ruston]

Wasn’t there a few posts about smart meters tripping rcd’s ??? Something to do with the comms
I think wrapping the meter in tin foil was suggested... I could be wrong.

and I had to read your name twice, @gcunit... wondered how it got past the sweary filter

Sounds like a difficult job dunnit.

 

[ipf]

Sounds like a difficult job dunnit.

They missed it by a c'untry mile...…..

I'd go with the element, from info given.

 

[snowhead]

Wasn’t there a few posts about smart meters tripping rcd’s ??? Something to do with the comms
I think wrapping the meter in tin foil was suggested... I could be wrong.

Yes there was a problem, the Smart meter was very close to the RCD.
And a foil barrier did solve the problem.

At the moment we don't know how close they are on this one.

The other thread;

Smart Meter Tripping RCD

Ines I’m no expert but how could the meter possibly trip that RCD since it’s feeding the premises and ahead of all your overcurrent and short circuit protection. It also seems unlikely that the wireless reading could trip a breaker. I wished I had an answer UK smart meters contain a SIM card...

www.electriciansforums.net

 

[gcunit]

Hi GC - sorry to hear about the tripping. Any chance of a pic of your Consumer Unit ?

Thanks for the early interest everyone. I have been considering the element - inspected it visually this morning, nothing obvious to me but I wouldn't know what to look for, or how to test it, but based on the responses I've had maybe I'll order a replacement.
[automerge]1581178678[/automerge]
Also got an off-peak circuit, fwiw:


[automerge]1581178679[/automerge]
Also got an off-peak circuit, fwiw:

 

[Midwest]

Which bit is tripping? Plus who's the naughty boy who put a Steeple mcb in a Wylex board?
Edit; i.e. is it just the RCD and or MCB?

 

[davesparks]

Thanks for the early interest everyone. I have been considering the element - inspected it visually this morning, nothing obvious to me but I wouldn't know what to look for, or how to test it, but based on the responses I've had maybe I'll order a replacement.

The fault may not be visible, it would need an insulation resistance test to be certain. But you could try a measuring resistance from the element terminals to the element casing with a multimeter if you have one. This won't be definitive but could give an indication.

Replacing components without testing them could turn in to an expensive waste of time, you might get lucky or you might not.

 

[Midwest]

The oven elements are only a few pounds though, from most spares shops.

 

[Megawatt]

The oven elements are only a few pounds though, from most spares shops.

Have you ever pulled your element out and read the resistance from one end to the other if it’s good it should be around 15 to 18 ohms

 

[telectrix]

Have you ever pulled your element out and read the resistance from one end to the other if it’s good it should be around 15 to 18 ohms

but that will only tell if it's got continuity. as the RCD is tripping, a leak to earth can only be detected with an insulation resistance test.

 

[Pretty Mouth]

- downstairs RCD trips, but the oven has its own fuse and never trips. Sometimes the garage fuse does trip, but I've turned the garage fuse off and the RCD has still tripped when using the oven.

Hi. When the garage breaker has tripped, has the RCD also tripped at the same time?

 

[davesparks]

Have you ever pulled your element out and read the resistance from one end to the other if it’s good it should be around 15 to 18 ohms

That's a bit low for the average UK oven element, 18ohms will be over 3kW, most ovens tend to be around 2kW so the resistance will be higher.

 

[James]

I would change the element, it will cost less than £30 I expect.
Espares is a web based supplier for most domestic apliences and do next day delivery.

An element change is fairly simple for most diy people, only basic tools required.

Before you start, isolate (turn off) power to oven at the wall switch.

When you have removed the covers and can see the cables to the element, mark them with a permanent marker and take pictures.

Cables will be push on, pull off spade terminals.

With the symptoms you are describing, it’s 80% likely to fix your problem.

Part will cost less than the call out fee of an engineer so it’s worth a go.