Grill only trips power out

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Hi ,
Every time I put the grill on (integral grill in cooker) the main CU RCD trips.
Initially I assumed it was just the naff cooker, so replaced it with another which does exactly the same. All four rings are fine as is the oven, but the grill trips out the RCD.

I did post about this a year ago and the general feeling was that there maybe an earth leak ? And that fitting an earth rod which would feed the cooker only may be a work around. I finally got around to fitting the earthing rod and unfortunately the problem is exactly the same.

I should say (if it helps) that the 30amp fuse in the CU does not blow, it's the RCD that trips.

The RCD in the CU is a 63A - 0.003a Hager item.


Any other suggestions please ?
 
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I would suspect you've got something that's causing a non insignificant amount of earth leakage (but not enough to trip the RCD on its own), and when you put the grill on, that causes enough additional leakage to trip the RCD.

Try unplugging all your other appliances (particularly anything involving water like washing machines etc) and see what happens - if the grill works then plug things back in one by one and see at what point it trips...
 
Excuse my ignorance, but would that be the issue with the cooker having it's own dedicated earth via the earth rod ?

The rod (via earth cable obviously) is connected to the oven only.
 
No, how any leaked current gets to earth is irrelevant - in simple terms an RCD measures the difference between the current going out on the line conductor, and the current coming back on the neutral - if they differ by more than the allowed amount it will trip. Any difference is normally accounted for by the current finding another path back to earth, either via the earth conductor and the main house earth or any separate rods etc, or via a human (which is what they're designed to protect against).

A lot of bits of kit do have a small amount of natural leakage (computer equipment being an obvious one that can cause problems with rooms full of them etc), but you can get minor faults (such as something getting a bit damp) that causes more leakage to occur.

What I suspect is happening in your case is you have something leaking more than trivial amounts due to getting e.g. damp, and when you then turn on your grill the little bit extra that creates is enough to trip the RCD.

Your earth rod will in theory make no difference, as all it is doing is providing an additional path to earth for any leaking current to use...
 
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Excellent info. Many thanks. I'm off to start unplugging stuff :D
 
I did post about this a year ago and the general feeling was that there maybe an earth leak ? And that fitting an earth rod which would feed the cooker only may be a work around. I finally got around to fitting the earthing rod and unfortunately the problem is exactly the same.
I haven't yet been able to find that old thread (any idea exactly when it was, or what the title was?) but I can't for the life of me see how an earth rod could help. If there were a leakage to earth (from anything), adding an additional earth rod would, if anything, make the situation worse.

The RCD in the CU is a 63A - 0.003a Hager item.
I presume that you mean 0.03A (30mA)? It would take only a tiny leakage to trip a 0.003A (3 mA) one.

Kind Regards, John.
 
Let us know how you get on - the other common one is outdoor lighting - if the seal perishes and a bit of water gets in it can cause this extra leakage...
 
I presume that you mean 0.03A (30mA)? It would take only a tiny leakage to trip a 0.003A (3 mA) one.

Kind Regards, John.

Apologies, you are quite correct, it is 0.03A. I haven't looked through all my posts, but it was certainly over a year ago.

Let us know how you get on - the other common one is outdoor lighting - if the seal perishes and a bit of water gets in it can cause this extra leakage..

Will do. Does leakage with outside lights only occur when the light is switched on ?

Thanks again chaps
 
Will do. Does leakage with outside lights only occur when the light is switched on ?

Sadly it can occur with it off as well, as it if provides a path from neutral (which is always connected even when it's switched off) to earth that is better than the path through the RCD then some current may flow through it...
 
Hmmm, bit gutted. Started by turning off and unplugging individually, but then in the end I pulled every plug socket in the whole house and shutdown the central heating and turned off the shower isolator and turned every light switch off, but it still trips out :(

Would fitting an upgraded RCD help or is that just papering over the cracks so to speak. ?
 
That would be against the regs unfortunately. You're best option now is probably to get an electrician in who can first test the RCD (as it could of course be the RCD is faulty), and if that is fine then do some insulation resistance tests, and/or disconnect the neutrals for circuits etc to try to identify the problem - as it sounds like the fault might be with some of your fixed wiring rather than an individual appliance.
 
Hmmm, bit gutted. Started by turning off and unplugging individually, but then in the end I pulled every plug socket in the whole house and shutdown the central heating and turned off the shower isolator and turned every light switch off, but it still trips out :( Would fitting an upgraded RCD help or is that just papering over the cracks so to speak. ?
An RCD rated above 30mA would, indeed, be papering over cracks - and would not be acceptable or worth having.

You obviously need to get to the bottom of this. Of course, the simplest eplanation would be that the grill is faulty (even though it's a replacement) - or, at least, resulting in an excessive leakage current. You're probably going to end up getting help from an electrician - certainly cheaper than keep on buying new cookers!

Kind Regards, John.
 
I was wondering if that might be the case.

Hey ho, by this time next year I could probably afford a spark to look at it :LOL:

Grilling food is far too healthy anyway ;)

Thanks Rebuke and John , I appreciate the assistance
 
The circuit earth has been disconnected from the cooker only and replaced with the earth from the earthing rod.

No idea about the rod suggestion, in fairness it could even have been from another forum, it's that long ago I can't remember
:confused:
 

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