Discuss Cooker hood trips other circuits on fuse board: what's going on? in the The Welcome Forum area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

OP from what you've described, your faulty (possibly) cooker hood is tripping circuits 5 or 6, when logic suggests it should be tripping circuit 4, i.e. kitchen sockets? Unless the kitchen fitter, pinched a supply from the upstairs ring to feed the cooker hood?

Think the sparking hob thing is artistic licence, and too much wine when cooking :)

You could unplug your cooker hood temporarily, and see if that stops the fault.

Why don't you first try disconnecting the cooker hood by turning off at the wall switch you mention. This should be a double pole switch, which should electrically disconnect it from it's supply. If the fault not longer manifest itself, then you could start looking at having the appliance tested for faults.

This does not explain why the hood on circuit 4, is tripping circuits 5 & 6. Sometimes with the best or worse intentions, kitchen fitters deputise themselves as electricians, and can make a right hash of things, this of course is not true of all kitchen fitter electricians. If, as it already has been suggested, these circuits have been cross connected, may be one possible line of inspection.

I note that your fuse board is populated with MEM ALB321 mcb's. I don't believe you could purchase an MEM ALB321 RCBO (Residual Current Breaker with Overcurrent)? You can however, I'm told, convert them to an RCBO, using a field fit RCD Pod. MEM are no more, but spares are obtainable from EATON, well not spares but replacements. Clutching at straws, perhaps these kits have not be assembled as per manufacturers instructions?

You seem to have some confidence & trust in the electrician who originally rewired your property. Why don't you see if he/she will come back and investigate these faults?

It is difficult to carry out fault finding from afar. The label on your fuse board suggest you are due an inspection anyway. :)
 
Why don't you first try disconnecting the cooker hood by turning off at the wall switch you mention. This should be a double pole switch, which should electrically disconnect it from it's supply. If the fault not longer manifest itself, then you could start looking at having the appliance tested for faults.

This does not explain why the hood on circuit 4, is tripping circuits 5 & 6. Sometimes with the best or worse intentions, kitchen fitters deputise themselves as electricians, and can make a right hash of things, this of course is not true of all kitchen fitter electricians. If, as it already has been suggested, these circuits have been cross connected, may be one possible line of inspection.

I note that your fuse board is populated with MEM ALB321 mcb's. I don't believe you could purchase an MEM ALB321 RCBO (Residual Current Breaker with Overcurrent)? You can however, I'm told, convert them to an RCBO, using a field fit RCD Pod. MEM are no more, but spares are obtainable from EATON, well not spares but replacements. Clutching at straws, perhaps these kits have not be assembled as per manufacturers instructions?

You seem to have some confidence & trust in the electrician who originally rewired your property. Why don't you see if he/she will come back and investigate these faults?

It is difficult to carry out fault finding from afar. The label on your fuse board suggest you are due an inspection anyway. :)

Thanks, Midwest: all sound advice. I think I will get our original sparky back and run everyone's suggestions past him. I'm pretty sure he tested to make sure that the three circuits in question were properly independent of each other bu there might be something he hasn't thought of. You're quite right about an inspection being due too: I only noticed that when I posted the photo! Slightly embarrassing...
 
You won't diagnose and fix this on a forum. You need a competent local spark with time, a mft and a clamp. Meter......

And money to pay them

P.s. I'm sure those are rcbo's
 
You won't diagnose and fix this on a forum. You need a competent local spark with time, a mft and a clamp. Meter......

And money to pay them
Fair comment. It's just that after having had 3 competent* local sparks draw blanks I thought I'd try a different tack for some input. Which I've got :)
* Though I guess some might measure competency by the ability to sort out the problem...!
 
Because each circuit you have is individually protected by an RCBO an earth fault on one circuit cannot affect another circuit.
However it is slightly possible, especially as the board is quite old, that the RCD portion of perhaps both circuits 5 and 6 is becoming damaged and perhaps sensitive to voltage transients, which could be generated by the cooker hood and possibly by the ignitor.
I would more probably expect that the problem is more related to a fault on one or both of the socket circuits or weak RCDs.
A potential sense check might be to get an electrician to initially test if the RCBOs function correctly and secondly to swap the RCBOs between circuits and see if the fault follows the RCBO or not.
Obviously if the tripping remains with the RCBO then the RCBO should be changed, however it would have to be a secondhand one as they are no longer available.
If the fault does not follow the RCBO but remains with the circuit then the concentration should be on testing the circuits for, probably, neutral earth faults either internally to the circuit or between circuits 5 and 6.
 
so some match making - Tom are you in Oxford? Midwest - how close are you to Oxford?
 
If it's two ring circuits then it's possible that someone got confused when connecting up the CU and interconnected two circuits, which would explain two rcbos tripping.
 
Because each circuit you have is individually protected by an RCBO an earth fault on one circuit cannot affect another circuit.
However it is slightly possible, especially as the board is quite old, that the RCD portion of perhaps both circuits 5 and 6 is becoming damaged and perhaps sensitive to voltage transients, which could be generated by the cooker hood and possibly by the ignitor.
I would more probably expect that the problem is more related to a fault on one or both of the socket circuits or weak RCDs.
A potential sense check might be to get an electrician to initially test if the RCBOs function correctly and secondly to swap the RCBOs between circuits and see if the fault follows the RCBO or not.
Obviously if the tripping remains with the RCBO then the RCBO should be changed, however it would have to be a secondhand one as they are no longer available.
If the fault does not follow the RCBO but remains with the circuit then the concentration should be on testing the circuits for, probably, neutral earth faults either internally to the circuit or between circuits 5 and 6.

More good stuff: thanks!
 
Yes, Midwest, are you within reach of Kidlington? I trust my original electrician but it would be good to get another pair of eyes to have a look...

PM me if your original electrician can't assist. Bear in mind if the RCBO's are defective as Richard suggested, their replacements are about £80 each. Hopefully your electrician might just find a simple fault with the wiring.
 
Is the trip random or cab you make it do it?

Sorry for slow reply. As the trip happens much less often than when we use the fan I've seen it as random, but some experimentation just now shows that I can make it happen most times that I switch from speed 1 to speed 2 on the fan, if I do it slowly. I got this idea from reading this other thread:
Cooker hood tripping RCBO - head scratcher - http://www.electriciansforums.co.uk/threads/cooker-hood-tripping-rcbo-head-scratcher.101736/page-2
...which I mostly don't follow (too technical for a layman like myself) but I get the drift that part of the problem was to do with something happening as the fan speed was changed. Our fan speed control is a slider, so switching between speeds means that you can have it momentarily between speeds as you move the slider along.

More information! Helpful or not, is the question?
 
Not sure what your point is, sorry... :)
The post that you linked to is describing a fault that trips the RCBO to which the circuit is connected. Your fault is tripping an unrelated RCBO so the fault resolution will be different.
Though it is possible that the fault on the socket circuits allows the same effect to occur, just through a fault rather than directly on the circuit, but a bit unlikely.
 
The post that you linked to is describing a fault that trips the RCBO to which the circuit is connected. Your fault is tripping an unrelated RCBO so the fault resolution will be different.
Though it is possible that the fault on the socket circuits allows the same effect to occur, just through a fault rather than directly on the circuit, but a bit unlikely.
Sure, I just thought any information might be useful. I was answering the question of whether I can repeat the fault at will. Even if the fault resolution is different, I thought the information about the fan speed adjustment might be helpful in working out why the fan causes anything to trip. To my (admittedly layman's) mind, why the fan causes a trip and why those particular circuits get tripped are the two elements of this puzzle.
 

Reply to Cooker hood trips other circuits on fuse board: what's going on? in the The Welcome Forum area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock