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assybish

Oven heats to c. 120 C then trips rcd

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assybish

Hi I am scientifically literate and can wire a house but not experienced in white goods.
I have an unused oven - been in store unopened for 6 years. Installed it .  On use all appeared fine until the temp got to about 120C then it tripped the RCD.

I have tested all programs and it only seems to trip on oven.

I can put grill 1/2 on and full on and no tripping. This suggests either bottom element or if the over top element is earth leaking and is using different parts of the element to the double grill component.

 

It does not have a control to out on only top element or only bottom element

 

This seems to be the top element assembly

 https://www.partmaster.co.uk/dual-grilloven-element-3200w/product.pl?pid=444889&query=Ikea+501.230.08+FRAMTID+OV+C10+S+GB+Dual+Grill%2FOven+Element+3200W+Genuine+spare

 

Is there any way I can test with a multimeter of otherwise what the fault is ie tope combo element or bottom element

 

. All else works up to full temp.

.It appears to be a whirlpool hybrid design for Ikea which is part OV9 and Part OC10 in controls but slightly different to either .

 

The data for it is ;

Ikea Framtid OV9 - OVC10/S
501.230.08 FCSM6
857924201510

 

Thanks

Thanks
Mike

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binky

the problem is most likely damp in the insulation around the oven. Turn it to a lower heat and leave for a while, then gently nurse temperature up a little at a time to dry it all out and it should be fine.

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Andy™

usually sign of a failed element. very common problem

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assybish
23 minutes ago, binky said:

the problem is most likely damp in the insulation around the oven. Turn it to a lower heat and leave for a while, then gently nurse temperature up a little at a time to dry it all out and it should be fine.

I've been trying this for a couple of weeks - got it up to 20C but doesn't take any higher .. But will take 250 of turbo fan grill or double grill alone hence my q about this oven as it seems to have 2 grill settings which heat 1/2 the grill , fan plus grill and oven - only the oven trips the rcd as the ovrn element anf 2 grill elements are all 1 unit should it be equally damp? 

Just now, Andy™ said:

usually sign of a failed element. very common problem

so a continuity test should show ? 

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roys
24 minutes ago, assybish said:

 

so a continuity test should show ? 

You might pick up the fault with a continuity tester but an insulation tester would be much better, as they can test by putting out a voltage of 250V or  500V

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assybish
Just now, roys said:

You might pick up the fault with a continuity tester but an insulation tester would be much better, as they can test by putting out a voltage of 250V or  500V

Sadly I don't have one ... but thanks

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Andy™
51 minutes ago, assybish said:

I've been trying this for a couple of weeks - got it up to 20C but doesn't take any higher .. But will take 250 of turbo fan grill or double grill alone hence my q about this oven as it seems to have 2 grill settings which heat 1/2 the grill , fan plus grill and oven - only the oven trips the rcd as the ovrn element anf 2 grill elements are all 1 unit should it be equally damp? 

so a continuity test should show ? 

 

insulation resistance test. a multimeter will probably work. also be aware that they can pass all tests, even at 500v, when cold. soon as they warm up, bang

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Doc Hudson

Is the RCD shared between other circuits?  If it is, there could be another appliance with some natural leakage, that when combined with a bit of oven natural leakage, the two combined trip  the RCD.

 

Doc H.

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Doc Hudson
8 hours ago, assybish said:

Hi I am scientifically literate and can wire a house 

 

I was just wondering why you mention "I can wire a house" in you opening line?  Do you mean, you can connect wires in loop to complete a circuit and make a Light/TV/Kettle/hot tub etc work?  Or do you mean you can design, install, test, certify, notify for part-P in accordance with the current edition of BS7671 wiring regulations? I would guess several members on here have seen, (and rectified), the work of DIY'ers, Builders, Cowboys etc. who all considered that they could "wire a house", whereas in reality it means absolutely nothing. If you could "wire a house" you should have a comprehensive understanding of insulation resistance testing, and earth leakage issues.  

 

Doc H.   

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assybish
16 hours ago, Doc Hudson said:

Is the RCD shared between other circuits?  If it is, there could be another appliance with some natural leakage, that when combined with a bit of oven natural leakage, the two combined trip  the RCD.

 

Doc H.

No it is a single radial circuit to the two built in overs 

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assybish

I have fully designed and wired a 6 bed house and barn conversion from scratch including running 25mm SWA armoured  and 3 consumer units including external outbuildings and lighting to the farm  - I is my own building! It was tested to part P by a friend who is an industrial electrical installation engineer. It passed fully with no issues and he said it was the best quality install he'd seen and offered me a job . My father was an electrician with his own company on industrial install . I mentioned it because I have never worked on a fan over and could find no circuit diagrams or service manual for the oven but have a reasonable scientific knowledge of electrical circuits and indeed electronic circuits .

 This over is unusual in that it appears to have 2 separate grill elements and the top oven element all on the same "element" but wired seperately. The bottom element is not operable separately from the top unlike the other oven. I was therefore trying to find out if there was a way of testing what is effectively 4 elements to find out what appeared to be causing an tiny earth leak to neutral . As some have usefully said simple testing may not show the issue as it may not leak until high temp. It also suggests that live testing may be required .. Well we had a so called professional oven electrician out and he did  cold test using continuity testing and earth leakage to neutral using a Multimeter and could find nothing and his suggestion was the spend 200£ on a new element but couldn't say which element was the issue. I find your comment somewhat unnecessarily aggressive as the forum isn't just for Professional white goods installers ! I stated I know how to wire a house correctly and in accordance with current regs as it shows I have a basic understanding of circuits , MCBs RCDs how they work etc BUT didn't have experience on white goods. I also do electronics and didn't mention that as it wasn't aposite . Diagnosing and testing an earth eak on a domestic circuit is straightforwards and I can do it .. but intermittent low level leaks that only appear at temps over 120C    clearly not hence my questions.Perhaps I am on the wrong forum ? 

 

Quote

I was just wondering why you mention "I can wire a house" in you opening line?  Do you mean, you can connect wires in loop to complete a circuit and make a Light/TV/Kettle/hot tub etc work?  Or do you mean you can design, install, test, certify, notify for part-P in accordance with the current edition of BS7671 wiring regulations? I would guess several members on here have seen, (and rectified), the work of DIY'ers, Builders, Cowboys etc. who all considered that they could "wire a house", whereas in reality it means absolutely nothing. If you could "wire a house" you should have a comprehensive understanding of insulation resistance testing, and earth leakage issues.  

 

Doc H.   

 

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Geoff1946

I would think your problem is most likely an element which has absorbed moisture into the mineral insulation.

As the element starts to warm up the moisture is driven towards the cold termination ends where its concentration results in low insulation resistance, and hence the rcd trips.

So, you are looking for an element which is used only in the circumstances where the circuit trips.

Ideally that element should be replaced, but as suggested above you may succeed in drying it out by keeping it at the highest temperature it attain can for a while, or by powering from a non-rcd supply for long enough to drive out the moisture.

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assybish
Just now, Geoff1946 said:

I would think your problem is most likely an element which has absorbed moisture into the mineral insulation.

As the element starts to warm up the moisture is driven towards the cold termination ends where its concentration results in low insulation resistance, and hence the rcd trips.

So, you are looking for an element which is used only in the circumstances where the circuit trips.

Ideally that element should be replaced, but as suggested above you may succeed in drying it out by keeping it at the highest temperature it attain can for a while, or by powering from a non-rcd supply for long enough to drive out the moisture.

Thanks Geoff .. what I was thinking .. my only issue is knowing whether it is the upper triple element VV expensive or the lower cheap one ..

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Andy™
11 minutes ago, Geoff1946 said:

 

Ideally that element should be replaced, but as suggested above you may succeed in drying it out by keeping it at the highest temperature it attain can for a while, or by powering from a non-rcd supply for long enough to drive out the moisture.

 

from experience of replacing probably hundreds of elements... drying it out wont work. for a new damp element yes, it can work, but otherwise no

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assybish
Just now, Andy™ said:

 

from experience of replacing probably hundreds of elements... drying it out wont work. for a new damp element yes, it can work, but otherwise no

Thanks Andy .. my only issue is which element .. because the poxy over can run 1/2 and full grill separately from upper oven BUT will not run upper and lower elements separately I can's fathom out which to replace the £100 top one or the £20 bottom .. money is tight :( 

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Andy™

get a generic element available from @kerching's corner shop (cpc.co.uk). far cheaper than genuine, and just as reliable

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assybish
Just now, Andy™ said:

get a generic element available from @kerching's corner shop (cpc.co.uk). far cheaper than genuine, and just as reliable

thanks mate ! :)

 

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Doc Hudson
22 hours ago, Doc Hudson said:

Is the RCD shared between other circuits?  If it is, there could be another appliance with some natural leakage, that when combined with a bit of oven natural leakage, the two combined trip  the RCD.

 

Doc H.

 

5 hours ago, assybish said:

No it is a single radial circuit to the two built in overs 

 

I will try again, as I didn't ask if the oven was on a radial circuit.   Is the oven circuit connected to an MCB that is supplied from an RCD, or does it have its own dedicated RCBO?  If it is an MCB supplied from an RCD, do other MCB's share this same RCD.  i.e. it is very common to have a consumer unit with one or two RCD which each supply multiple MCB's   In addition to what the others have said regarding elements, it is also true that some oven manufactures used to recommend their appliances were NOT connected via an RCD due to natural leakage issues.   Have you verified that you RCD is operating within its correct specification, i.e. not over sensitive? Multiple circuits each with a proportion of natural leakage can cause RCD's to trip, when there is no actual genuine single fault. You may well have a faulty element, But it is also true that you may not. I was just trying to establish if you have confirmed your RCD symptoms occur with a known good RCD (or RCBO) and no other circuits that could influence the operation of this RCD (or RCBO)?

 

Doc H.

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Doc Hudson
5 hours ago, assybish said:

1) I have fully designed and wired a 6 bed house and barn conversion from scratch

2) It was tested to part P by a friend who is an industrial electrical installation engineer.

3) I find your comment somewhat unnecessarily aggressive as the forum isn't just for Professional white goods installers !

4) I stated I know how to wire a house correctly and in accordance with current regs as it shows I have a basic understanding of circuits , MCBs RCDs how they work etc

 

1) Still curious and interested to know who signed the declarations for design and install on the electrical certificates for this "notifiable" work you described?

2) I think you will find it should be designed, installed, inspected & tested in accordance with BS7671. Then Notified for compliance with Part-P building regulations. as ther is "No testing to Part-P".

3) I am not sure we actually have any professional white goods installers, as this is an electricians forum.

4) If you had a basic understanding of MCB's, & RCD's etc, I would have expected you to understand more clearly the reason for asking if the RCD was shared across multiple circuits.

 

We occasionally get people who ask questions, but for some reason dislike answering questions that would help others answer their questions within a greater context to their ability, knowledge and experience. We also get people describing things incorrectly which mean answers could be incorrect or missing a significant piece of detail. So we often need to ask questions to establish the full picture and make sure any key facts are not overlooked. Some faults do have multiple potential causes, so a few extra tests and checks can help getting to the final solution, hence my additional questions to compliment the comments already posted. 

 

Doc H.

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Andy™
7 hours ago, Doc Hudson said:

3) I am not sure we actually have any professional white goods installers, as this is an electricians forum.

 

professional white goods installers... thats a more technical and posh version of 'delivery driver'

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Sharpend
20 hours ago, Andy™ said:

 

professional white goods installers... thats a more technical and posh version of 'delivery driver'


no no no, their correct title is ‘ professional white goods installers of newly delivered white goods’ 

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UNG

 

On 18/01/2020 at 18:29, assybish said:

I have fully designed and wired a 6 bed house and barn conversion from scratch including running 25mm SWA armoured  and 3 consumer units including external outbuildings and lighting to the farm  - I is my own building! It was tested to part P

 

 

Was this designed to Part P or BS7671

Installation with outbuildings!!!! I wonder how their RCD protection was designed in to the installation

 

On 18/01/2020 at 18:29, assybish said:

It was tested to part P by a friend who is an industrial electrical installation engineer. It passed fully with no issues and he said it was the best quality install he'd seen and offered me a job

My father was an electrician with his own company on industrial install . forum ?

 

 

So why are they not able to find the fault I would be worried if they were out of their depth. Although it is worrying that an electrical installation engineer comes to your job and says "it was the best quality install he'd seen and offered me a job" says a lot about his work and any work he has supervised

 

On 18/01/2020 at 18:29, assybish said:

 Diagnosing and testing an earth leak on a domestic circuit is straightforwards and I can do it .. but intermittent low level leaks that only appear at temps over 120C    clearly not hence my questions.Perhaps I am on the wrong forum ?

 

 

It would appear that you cannot do what you claim as it appears you do not have the necessary test equipment to do it so why make the statement

 

RCD's are not a perfect piece of equipment even brand new out of the box they can be faulty testing RCD's as little as 6 months after initial install they can give a totally different set of results and be faulty or over sensitive despite being within the requirements at installation. Try ramp testing the RCD you may find it's trip current is well below the 30mA threshold

 

From past experience general RCD's on circuits supplying cooking equipment can always be problematic I would swap this circuit to an RCBO to try and isolate the issue from a possible cumulative earth leakage of the other circuits, this is something which should have been considered at the design stage

 

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