Oven housing keeps tripping rcd

[Sd298]

Hi,

Had an issue recently where rcd would randomly trip, this was eventually narrowed down to a faulty rcd. Once the rcd was replaced i found out the random trips were down to the oven, now the rcd trips immediately as soon as oven is connected up to the mains and switched on. The weird thing is, if i remove the back housing of the oven and turn it on, oven works fine ( L N and earth still connected. Pic attached of housing. Hoping someone can offer any suggestions as to what issue could be.

 

[EFLImpudence]

Had an issue recently where rcd would randomly trip, this was eventually narrowed down to a faulty rcd.

A faulty safety device is always the first choice.

Once the rcd was replaced i found out the random trips were down to the oven,

So not the RCD.

now the rcd trips immediately as soon as oven is connected up to the mains and switched on.

Yeah well, it would if there is a fault wouldn't it?

Elements are often the primary cause of faults.

The weird thing is, if i remove the back housing of the oven and turn it on, oven works fine ( L N and earth still connected. Pic attached of housing. Hoping someone can offer any suggestions as to what issue could be.

Perhaps the back being connected to the rest of the oven and the fault.

Probably if you put the oven in the back yard, it will also stop causing trips.

 

[Sd298]

Yes, the rcd was faulty as it was tripping intermittently so i could not locate the faulty appliance, once it was replaced of course the faulty appliance ( oven ) became known. Have tested all the elements with a meter and they are fine

 

[jj4091]

Make and model may help you get an answer. I once had a strange RCD tripping fault on a Bosch oven where the pins on the rear of the suppressor ( a small pcb inside that the mains cable connects to ) were shorting to the frame only when the oven warmed up. So perhaps fitting the rear cover is distorting another part of the body of the oven is causing a short to earth on yours. Also a better pic of the rear of the oven might help, can't really see anything form the one you posted.

 

[Sd298]

thankyou for your help. Have attached pics with model and rear.

 

[Sd298]

hmm, seems the earth wire was connected to the same terminal as the neutral wire on the housing connection, once i moved the earth wire down and connected it to the earth terminal, that seems to have solved the problem. Not sure why the manufacturer would have connected the neutral and earth to the same terminal in the first place.

 

[JohnW2]

hmm, seems the earth wire was connected to the same terminal as the neutral wire on the housing connection,

If the neutral and earth were connected together, the RCD ought to have been 'permanently tripped' - at least, if anything else significant in the house was 'turned on'.

.... Not sure why the manufacturer would have connected the neutral and earth to the same terminal in the first place.

See above - they wouldn't have done that. How long have you had this oven, and was it previously working OK without tripping the RCD?

Kind Regards, John

 

[ebee]

I am a bit concerned by your logic that a faulty RCD was causing random trips whereas now only the oven causes trips with the new RCD,that does not make sense initially so I wonder if some mistaken assumptions are being made.

Do not take that as a criticism - it is not completely impossible but I think extremely unlikely.

How have you actually confirmed that tge RCD was faulty? Test meter perhaps.
This would give you some info about the actual likely parameters of that RCD.
Only the oven causing the trip on the new RCD could be indicative of the actual variance of the two RCDs whilst both are within spec (or both outside the spec even).

It could be an indication that something else has changed slightly , example the oven has been moved, jolted, banged, got wetter, dryer, etc etc etc..

It was not unknown a few years back for meto rewire a house and then get a complaint i had made a fault because that new fangled RCD kept tripping everytime the WW1 electric fire with exposed elements and exposed conductors in the flex was used. "Its always been ok before the rewire!" . No it was not its always been potentially lethal but now the RCD has detected it., throw the fire away.

So, all may not be as it appears, get both RCDs tested if it is possible and look for a source of intermittent faults would be my advice

 

[JohnW2]

I am a bit concerned by your logic that a faulty RCD was causing random trips whereas now only the oven causes trips with the new RCD,that does not make sense initially so I wonder if some mistaken assumptions are being made. ... Do not take that as a criticism - it is not completely impossible but I think extremely unlikely.

I agree, and the story did all sound a bit confusing and, as you say, 'unlikely'.

The only interpretation I could think of that there were, indeed, 'random trips' occurring (maybe due to a faulty RCD) ,but they were so relatively common that it was at the time not apparent that some of the trips were associated with an 'identifiable event' - and that, since the RCD has been replaced, the trips now only occur whenever the oven is switched on (with its back in place).

As you say, that would seem like a very unlikley scenario - but otherwise it's hard to see why there should (apparently) have been a change in behaviour (per what I've just written, when the RCD ws replaced.

However, on the basis of common sense and "common things are common", it would seem most likely that, in one way or another, all of the trips have always been related in some way to the oven, with perhaps none of them actually being 'random'.

The situation certainly warrants 'proper investigation'.

Kind Regards, John

 

[securespark]

Probably if you put the oven in the back yard, it will also stop causing trips.

Presumably, you would disconnect it?

 

[securespark]

Could it be a pressure fault when the back panel is in place?

 

[opps]

hmm, seems the earth wire was connected to the same terminal as the neutral wire on the housing connection, once i moved the earth wire down and connected it to the earth terminal, that seems to have solved the problem. Not sure why the manufacturer would have connected the neutral and earth to the same terminal in the first place.

Erm.. ok... did it work previously?

If yes, how?

Might it not be the case that you have removed the earth bonding?

I am not an electrician but I assume that it worked previously...

 

[JohnW2]

Erm.. ok... did it work previously? If yes, how?

Indeed. As I've said, if the neutral and earth were connected, it would never have worked (without tripping an RCD) if there was any other electricity being used in the house.

Might it not be the case that you have removed the earth bonding?

I presume you mean 'earthing'. However, if it really was previously connected to the neutral, then it's not a bad thing that it has seemingly now been connected to the right place!

I am not an electrician but I assume that it worked previously...

Indeed, I've made the same 'assumption'- but, despite that,, have asked the question (but have not yet had a reply).

As everyone should know, I'm not an electrician, either!

Kind Regards, John