Induction hob trips RCD

[reg091]

Beko HII64201MT induction hob fitted to replace previous induction hob.

No change in wiring. Old hob worked fine.

Hob is connected into DP isolator switch. When I turn the switch on the 80A 30 mA RCD trips.

If I disconnect the hob wiring from the DP switch there is no problem. This suggests to me a problem with the hob rather than switch/cabling back to CU.

If I connect just the L and N of the hob (leaving E disconnected) it does NOT trip the RCD. This seems fairly obvious to me that there is earth leakage in the hob, but are there any other possibilities??

It worked fine for a few days and has now developed this problem.

NOTE: I am not even turning the hob on, just turning on the isolator switch to it trips the RCD (leaving the switch on and trying to reset the RCD doesn't work, the RCD will not hold on).


Any thoughts welcome!

 

[Scally-Ho]

From your wording, it seems to me that the hob unit has an 'earthy' fault. Rather than sod about with it, I'd return it as faulty while it's still under warranty.

 

[Jurassicspark]

Is it a “new” hob?

 

[Murdochcat]

Have you been cleaning it ?

 

[reg091]

Thanks all. It is a brand new hob so obviously I will get it replaced if it is faulty, which seems likely but I just wanted a sanity check if I was missing something.

I haven't cleaned it but I did have a pan boil over slightly. But if it can't take water on the glass surface then what use is it??! I suppose water could have got under the seal to the worktop but 1) unlikely as it is a seal after all, and 2) not much chance of water getting inside it if it did.

So, I am currently running it without an earth. Obviously not a good idea (although there are no metal parts above the counter).

 

[Taylortwocities]

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

 

[reg091]

Thanks. I'll get it changed.

 

[Harry Bloomfield]

So, I am currently running it without an earth. Obviously not a good idea (although there are no metal parts above the counter).

If the RCD is tripping, there is live leakage to earth. If you are running it with the earth disconnected, then that leakage to earth, will make any external metalwork live - an extremely dangerous situation, for anyone going near, or using the hob.

 

[martygturner]

Induction hobs by their very nature can induce a large earth leakage whilst working fine so you could easily get the same result with a new hob. You could reconnect the board and turn off all the other circuits on that RCD, it could just be a case of too much leakage on that rcd.
=Solutions could be to swap the hob circuit to the other rcd or fit an rcbo and connect that into the non protected neutral bar.

 

[Taylortwocities]

Induction hobs by their very nature can induce a large earth leakage whilst working fine so you could easily get the same result with a new hob. You could reconnect the board and turn off all the other circuits on that RCD, it could just be a case of too much leakage on that rcd.
=Solutions could be to swap the hob circuit to the other rcd or fit an rcbo and connect that into the non protected neutral bar.

Nah. Never had that issue. Get a replacement one.

 

[ebee]

olutions could be to swap the hob circuit to the other rcd or fit an rcbo and connect that into the non protected neutral bar.

Do we know that the CU is a dual RCD type anyhow?

I reckon an insulation tester for Live to E might spot a possible problem (Connect the Lives = L & N linked together to one terminal and the E to the other terminal then insulation test at 250V then 500V would give initial indication of a possible problem)

 

[reg091]

Induction hobs by their very nature can induce a large earth leakage whilst working fine so you could easily get the same result with a new hob. You could reconnect the board and turn off all the other circuits on that RCD, it could just be a case of too much leakage on that rcd.
=Solutions could be to swap the hob circuit to the other rcd or fit an rcbo and connect that into the non protected neutral bar.

Even when it is not turned on though?

 

[Rodders53]

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

Note most hobs have electronic controls and that electronics uses power even when all the "burners" are off. Likely that controller or some radio frequency interference suppressor component has gone faulty.

Things often fail in the early days of use (bathtub curve).

 

[ebee]

Even when it is not turned on though?

If it`s only single pole switching of what is turned on or off then yes.
If, example each element in turn has DP switching it isolates that bit, if all such are so isolated then it`s nearly the equivalent of isolating you local switch on the wall (unless someone has attached some sort of filter before the local element control.
Any Neutral connection still in circuit can still trip an RCD.

 

[reg091]

Engineer attending Tuesday to "repair" hob.