tripping induction hob

[Quantum dan]

Hi guys

Interested in your thoughts here. I recently installed a new circuit to supply an induction hob and oven. The circuit is supplied via a 40 amp rcbo. The rcbo however is intermittently tripping, sometimes when it's not even in use and stone cold I.e no fan etc running. I know the loading is correct and this is not an overload fault.

I'm thinking it's a faulty oven unit/hob unit - it's brand new and straight out the box.

Or do induction hobs require a type c breaker to cope with the inductive load - if that's how they work? Iv fitted induction hobs before in type b breakers and never had a problem.

Any thoughts?

Thanks.
Dan

 

[Deleted member 72666]

Get some IR testing done on the appliance and then you'll have a better picture.

 

[Farmelectrics]

as above ir test

 

[ruston]

It is quite common for elements to absorb moisture and trip RCD's. This is why it will do it when not in use.
Is the double pole switch off when it is tripping?

 

[Quantum dan]

It is quite common for elements to absorb moisture and trip RCD's. This is why it will do it when not in use.
Is the double pole switch off when it is tripping?

No. The dp switch is on.

 

[ruston]

It may well be a mineral element then. Sometimes drying them out solves the problem, but there is no guarantee that it will not do it again. RCD's are not ideal for cookers unfortunately. (you will have to be ingenious to dry it out lol :wink5::wink5
Try the suggestions for IR first though.

 

[davesparks]

Mineral element in an induction hob?

 

[ruston]

Mineral element in an induction hob?

It has ovens too.

 

[leo79]

The very first induction hob I did many moons ago had the same problem, after speaking to the manufacture I was advised to run feed in swa and omit rcd protection as induction hobs had a tendency to trip rcd.

Complete bo***cks I thought but as the cu was literally in the next cupboard and house was still being refurbished this is what I did.

I've never had issues with induction hobs and rcd's since that one but it could be same make? Cant remember make of that one but probably called something like Bonko bought for peanuts off ebay.

 

[leo79]

Have you tried a different RCBO?

 

[DPG]

Have you tested the RCBO? Daz

 

[R G]

If the circuit is all ok and test confirm circuit is not faulty you could try the circuit for a short time on an MCB , then once elements have warmed up replace MCB with the RCBo again , worth a try that is of course if the RCBo is not faulty and tests out alright , disconnect circuit completely to carry out the RCD test though..

 

[UKMeterman]

Looks like some electricians on this thread have no concept of what an induction hob is!. It is basically a high power low frequency radio transmitter connected to a coil under each pan location. The pan is heated by eddy currents induced in the pan. Note that such a hob will have a large number of RF filters including caps L to E and N to E. These caps will cause a large amount of leakage current and also provide a good path for any RF noise from elsewhere to earth. I would suggest first clamp it to find out the level of earth leakage and then fit a good RCD that also has transient suppression.

 

[ruston]

But it is tripping with double pole switch on and hob off.
It also has an oven.

 

[UKMeterman]

But it is tripping with double pole switch on and hob off.
It also has an oven.

The RF filters are probably in circuit all the time, need to get your clamp meter out.

Thanks