Induction hob trips RCD

[endecotp]

So, I am currently running it without an earth. Obviously not a good idea

FFS! Correct, it is indeed “obviously not a good idea” - so why the *%£@ are you doing it!1!qq!!!!!

The purpose of the earth connection is so that power is disconnected when there is a live-to-earth fault. You established beyond doubt that there was a live-to-earth fault. You should have immediately stopped using it and disconnected it.

 

[endecotp]

Induction hobs by their very nature can induce a large earth leakage whilst working fine

Unlikely to trip immediately though?

Maybe the “engineer” who comes on Tuesday will actually try to measure the leakage. (Ha, as if!)

 

[reg091]

FFS! Correct, it is indeed “obviously not a good idea” - so why the *%£@ are you doing it!1!qq!!!!!

The purpose of the earth connection is so that power is disconnected when there is a live-to-earth fault. You established beyond doubt that there was a live-to-earth fault. You should have immediately stopped using it and disconnected it.

Because it has no metal parts accessible. I wouldn't think of it if it was an oven or similar.

 

[reg091]

Maybe the “engineer” who comes on Tuesday will actually try to measure the leakage. (Ha, as if!)

Yeah right! The wording used on the chat when I booked the service call was "he will apply the fix." Suggesting perhaps it is aknown issue. Although it was an Indian call centre so could just have been odd use of language.

 

[endecotp]

Because it has no metal parts accessible.

It could still catch fire, or fail in some other dangerous way, if there is a loose live wire flapping around inside.

 

[flameport]

Although it was an Indian call centre so could just have been odd use of language.

It's call centre - they are just reading a script containing a small selection of stock answers.
Location of call centre is unrelated.

 

[ericmark]

I had a problem with a set of scales, the earth leakage was too high when doing the PAT test, it seems it was fitted with a filter to take the spikes out of the supply, which was causing the leakage, the fix was to remove the filter, it may be something similar, there may be some filter which causes some leakage.

We can have from memory a few mA leakage, seem to remember maximum is 3 mA unless special earthing is done. All items together should not exceed 30% of the RCD rating, so for a 30 mA RCD that's 9 mA, and the RCD should trip between ½ (15 mA) and full (30 mA) but in general it will trip at around 26 mA.

So much depends on how much is already leaking,

here it shows my house is leaking 8 mA, since it feeds 14 RCBO's (RCBO is a MCB and RCD combined) I am well within limits, here I am doing a ramp test, one could do it with all connected and with nothing connected and the difference would be back-ground leakage. We can also test without items being live, with this tester, however it uses DC not AC for the test, so it can give a false pass if leakage due to capacitive or inductive linking. However my point is the induction hob could simply be the last straw, but likely it is faulty as 3 mA should not normally tip the ballance.

 

[morqthana]

Yeah right! The wording used on the chat when I booked the service call was "he will apply the fix." Suggesting perhaps it is aknown issue.

As soon as I read that they were sending someone to fix the hob, I thought "they know what's wrong with it".

Please pay close attention to what he does and/or replaces and try to question him about the problem.

 

[reg091]

Thanks@ericmark. That is what I am hoping is not the case as it will take a lot more diagnostics to pin down. Fingers-crossed it's a faulty hob!

 

[reg091]

As soon as I read that they were sending someone to fix the hob, I thought "they know what's wrong with it".

Please pay close attention to what he does and/or replaces and try to question him about the problem.

That's my take on it too. I will be quizzing him.

 

[Taylortwocities]

Hob faulty. Disconnect it and get it replaced immediately. Do not use without an earth connected

Oh, I wish I had said that.

It is faulty. Get it changed under warranty.
PS Don't energise it without an earth connected.

 

[Rodders53]

Oh, I wish I had said that.

But you did.

I merely repeated it to try to reinforce the point to the OP who is ignoring the advice given... and not only by you (and I)!

 

[Harry Bloomfield]

Oh, I wish I had said that.

It's the echos in here!

 

[reg091]

But you did.

I merely repeated it to try to reinforce the point to the OP who is ignoring the advice given... and not only by you (and I)!

OP here. I posted the question to see if my conclusion the hob is faulty is likely correct. I'd guess 70% of the replies confirmed that so I booked the service call.

Advice on other issues is if course welcome.

 

[martygturner]

Unlikely to trip immediately though?

Maybe the “engineer” who comes on Tuesday will actually try to measure the leakage. (Ha, as if!)

Depends on the electronics package... Neff ones pre soak the induction coils via the TRANSFORMER ( clue there), cheaper ones tend to use capacity charging and both would give a fair amount of leakage when you apply power, neff have a builtin out saying they expect 6-8mA as it cycles on .. why do you think induction hobs take min of 30 seconds to warm up before use ? One wonders what they are doing ??

As I said the quickest way is to flip off all the other circuits and just flip only the induction hob on...especially if the call out is one of those dog sh!te ones that charge if no fault is found with their kit.