New electric cooker causing power to trip at fuse. The fuse is reluctant to flick back on after.

[Stephen]

When it trips, do you leave everything on and just turn it back on?

If so, the next time it trips, turn everything off in the fuse box except the RCDs, turn the big RCD that trips back on and then turn them back on one at a time... do the cooker last.

It's possible the fault is in the element and as it cools down it goes away and allows you to reset the RCD, but following this procedure above should (if the fault is only on the cooker) allow you to get the power back on quicker.

You shouldn't really keep turning it on under load either as it will damage the contacts.

I will do that and I agree it isn't ideal.

The cooker rarely gets up to temperature when it trips.

Also I have used the cooker for 10 days with no trips.... seems sporadic.

 

[SparkyChick]

I will do that and I agree it isn't ideal.

The cooker rarely gets up to temperature when it trips.

Also I have used the cooker for 10 days with no trips.... seems sporadic.

It's not just faults that can trip RCDs. It could be cumulative leakage, where under a certain set of circumstances there is over 30mA of leakage, could be sometimes there is leakage in the junction box and others not.

Loose connections can also trip RCDs.

 

[123]

Out of interest, who did the works to extend the cooker circuit and put that junction box in the wall?

 

[Stephen]

It's a TT, the upfront RCD is a relic of the previous DB

Hi what do you mean my this please? I tried googling the acronyms to no joy. Appreciate your help

 

[Stephen]

Out of interest, who did the works to extend the cooker circuit and put that junction box in the wall?

My father in law.

Very competent although admittedly not a trained electrician.

Thanks

 

[SparkyChick]

Hi what do you mean my this please? I tried googling the acronyms to no joy. Appreciate your help

TT is an earthing system, you'll have an earth rod (the cable that disappears through the wall most likely). Because TT doesn't allow much current to flow under some fault conditions, RCDs were added upfront to improve safety.

Now you have RCDs in your consumer unit, it's not needed. If the CU was metal, we might install a 100mA time delayed RCD to protect the connections between the consumer unit and the meter, but for all intents and purposes you don't need it. It should have been removed when the consumer unit was upgraded.

 

['mr2'gd4u]

Hi what do you mean my this please? I tried googling the acronyms to no joy. Appreciate your help

Your setup has an earth spike in the ground, that's why there is no earth supplied by your dno.

 

[Stephen]

TT is an earthing system, you'll have an earth rod (the cable that disappears through the wall most likely). Because TT doesn't allow much current to flow under some fault conditions, RCDs were added upfront to improve safety.

Now you have RCDs in your consumer unit, it's not needed. If the CU was metal, we might install a 100mA time delayed RCD to protect the connections between the consumer unit and the meter, but for all intents and purposes you don't need it. It should have been removed when the consumer unit was upgraded.

Thank you so much for all your help.

Really appreciate all your help.

Thanks

 

[littlespark]

I’ve just seen exactly the same thing. Cooker supply cable jointed in the old 45A switch box and tiled over.
Joint made in a J401 spur box which I believe is only rated 30A
Luckily there was enough spare cable in attic to reroute and move to where it needed to be.
Also needed to rewire the rfc in kitchen where I found a spur off a spur off a spur off the rfc.

 

[SparkyChick]

Unfortunately in Wales, electrical work in your kitchen is covered under Part P of the building regulations. There should be at least a Minor Electrical Installation Works certificate and your local authority building control department should have been notified that the work has been carried out.

You're technically responsible for the notification or lack of.

It can be corrected, but you'd need to employee an electrician to carry out an Electrical Installation Condition Report and probably pay your LABC a fee to have the work regularised.

 

['mr2'gd4u]

Out of interest, who did the works to extend the cooker circuit and put that junction box in the wall?

You disagree with MF connections when buried?

 

[SparkyChick]

I should add, if you wanted to get it regularised, you would need to discuss it with your LABC as some are fussy and only allow this kind of thing to be done by certain scheme members or certain companies.

 

[Stephen]

I’ve just seen exactly the same thing. Cooker supply cable jointed in the old 45A switch box and tiled over.
Joint made in a J401 spur box which I believe is only rated 30A
Luckily there was enough spare cable in attic to reroute and move to where it needed to be.
Also needed to rewire the rfc in kitchen where I found a spur off a spur off a spur off the rfc.

Yeah ... sounds similar to my cooker.. the one we used was 30amp

Axiom Junction Box 30A 3 Terminal White - https://www.toolstation.com/shop/p28404

 

[SparkyChick]

You disagree with MF connections when buried?

Personally I disagree with anything buried in the wall if there is no indication at all that it's there. It's a disaster waiting to happen if there's cables floating around and no accessories to give even a hint they exist.

Jointing method doesn't come into it.

 

[123]

My father in law.

Very competent although admittedly not a trained electrician.

Thanks

I'll beg to differ on that. Burying 32A junction boxes in the wall is anything but good, it's downright shoddy. Chances are some cable is now no longer in safe zones either.

 

[123]

You disagree with MF connections when buried?

Yep, @SparkyChick in post #54 covers why. Plus most MF JB's are not designed to be plastered over, something like a resin joint might be but just who does that in a kitchen.

 

[Stephen]

Do you have a photo of this junction box, before it was plastered over (the insides, what connectors were used)?

Axiom Junction Box 30A 3 Terminal White - https://www.toolstation.com/shop/p28404

Was this connection box.

Was cooker cable joined inside with screws.

 

[GBDamo]

Axiom Junction Box 30A 3 Terminal White - https://www.toolstation.com/shop/p28404

Was this connection box.

Was cooker cable joined inside with screws.

This isn't getting better.

 

[123]

Axiom Junction Box 30A 3 Terminal White - https://www.toolstation.com/shop/p28404

Was this connection box.

Was cooker cable joined inside with screws.

I'm assuming the cooker cable comes from the ceiling down to this, has it now moved to the left or right, with this junction box and cable plastered and tiled over?

 

[GBDamo]

We've all seen this done before, I think, but it dont make it correct, not just for the reasons already mentioned.

It's one of those things that could be fine and last years but now the OP has a fault these are the things you really wish you hadn't done.

It can be proved that this junction is not the cause of the fault, if that's the case, but it will never be correct and it will always be a potential hazard.

 

[Stephen]

I'm assuming the cooker cable comes from the ceiling down to this, has it now moved to the left or right, with this junction box and cable plastered and tiled over?

Ok so your right the cable came from the ceiling... it used to be directly connected to the isolation switch at this location.

In order to move the isolation switches nearer to the Cooker and from the middle of the wall we needed to extend the wiring that's where my father in law contacted a electrician whom said this would be fine. The junction box was used at the location and then left buried in the wall.

Yes it is plastered over.... not tiled.

The cooker wire comes from this location to the isolation sockets.

This then goes to a junction box (cooker one) then from that to the oven

Ok so your right the cable came from the ceiling... it used to be directly connected to the isolation switch at this location.

In order to move the isolation switches nearer to the Cooker and from the middle of the wall we needed to extend the wiring that's where my father in law contacted a electrician whom said this would be fine. The junction box was used at the location and then left buried in the wall.

Yes it is plastered over.... not tiled.

The cooker wire comes from this location to the isolation sockets.

This then goes to a junction box (cooker one) then from that to the oven

When say cooker junction box it's a 1 gang 45 amp box fixed to the wall behind the cooker

 

[Wilko]

Hi - I think its likely your recent works are the cause. The joint(s) or the oven itself. Any Certificate from the new Consumer Unit job? I agree with earlier advice, I think you need a friendly Electrician to help you now .

 

[Stephen]

We've all seen this done before, I think, but it dont make it correct, not just for the reasons already mentioned.

It's one of those things that could be fine and last years but now the OP has a fault these are the things you really wish you hadn't done.

It can be proved that this junction is not the cause of the fault, if that's the case, but it will never be correct and it will always be a potential hazard.

Thanks for your advice.

I appreciate your time to help.

Thank you

 

[Wilko]

Hi - I think its likely your recent works are the cause. The joint(s) or the oven itself. I agree with earlier advice, I think you need a friendly Electrician to help you now. And probably not the one that said burying that JB in the wall was ok, just saying .

 

[Stephen]

Hi - I think its likely your recent works are the cause. The joint(s) or the oven itself. Any Certificate from the new Consumer Unit job? I agree with earlier advice, I think you need a friendly Electrician to help you now .

Yes there is a certificate I believe.

What's best way to find a reputable electrician.

What the likely cost of an investigative visit.

My priority now is to get it tested and checked

Thanks

 

[MFS Electrical]

You disagree with MF connections when buried?

I was wondering that?
maybe was a disagree because it shouldn’t have ever been buried as burying the joint effectively removes the safe zones to run the cable in?

 

[Deleted member 9648]

look for a local guy who has been around a long time. Small guys rely on reputation and if they are long established it is normally a good sign. NICEIC or other schemes are no longer a guarantee of quality. An hours labour should be sufficient to find (but not necessarily rectify) the cause.

 

[123]

Ok so your right the cable came from the ceiling... it used to be directly connected to the isolation switch at this location.

In order to move the isolation switches nearer to the Cooker and from the middle of the wall we needed to extend the wiring that's where my father in law contacted a electrician whom said this would be fine. The junction box was used at the location and then left buried in the wall.

Yes it is plastered over.... not tiled.

The cooker wire comes from this location to the isolation sockets.

This then goes to a junction box (cooker one) then from that to the oven

When say cooker junction box it's a 1 gang 45 amp box fixed to the wall behind the cooker

I wouldn't get your father in law to do more electrical works for you (harsh but true). Also wouldn't get the electrician he contacted who said this would be ok, I'd be getting another electrician out to look at it.

 

[Stephen]

Well I thank you all for your help and comments

more than likely the fault will be due to a fault due to a damp element when I think of it sitting unused for a while

I understand the wiring and works were not done to a standard you all deem acceptable and I will have to save to afford a qualified electrician to test and resolve.

Next steps

• Work overtime
• Get an electrician to test the wiring
• Hopefully find the fault
• Fix it
• Never attempt to sort the kitchen on a budget again.

I am curious would I ever now be able to obtain a certificate of safety with this buried JB?

 

[MFS Electrical]

Well I thank you all for your help and comments

more than likely the fault will be due to a fault due to a damp element when I think of it sitting unused for a while

I understand the wiring and works were not done to a standard you all deem acceptable and I will have to save to afford a qualified electrician to test and resolve.

Next steps

• Work overtime
• Get an electrician to test the wiring
• Hopefully find the fault
• Fix it
• Never attempt to sort the kitchen on a budget again.

I am curious would I ever now be able to obtain a certificate of safety with this buried JB?

Not being funny but no spark in their right mind would ever issue an Electrical installation Certificate or even a minor works certificate for work they haven’t done or at least witnessed every stage of. Anyone who says that they will should really be avoided like the plague. The best you may get is an EICR. (Electrical Installation Condition Report) I’m not familiar with the PART P side of things as I’m not in England or Wales but I don’t think that an EICR would be enough to certify that it complies without additional charges at the very least.

 

[Gavin John Hyde]

Is it just me or is the edge of that double socket sitting on top of the 45A DP Switch?

quite common with the new metal accessories as they are just that bit wider than older plastic ones so if the back boxes are too close they over lap. i suspect the cause is that they have used dual backboxes so the socket and middle fcu are in same one, not enough space in middle for them, hence the over lap.

 

[SparkyChick]

As I said earlier in the thread... if you want to get it regularised by building control, you'll need to have a chat with them and find out who they'll accept an EICR from.

Once you know who they'll accept it from, you can engage someone and have them do the EICR and then submit it to BC.

I've done one, cost the lady over £300 I think in building control fees, plus my time and materials (in her case 3 days of testing and remedial work).

 

[Gavin John Hyde]

With those AEG ovens they use hex screws and unless you crimp the cable ends you have to split it around the screw. its very easy to get a loose strand that is sticking out touching the oven body. which is at earth potential and then trip the rcd. I have had it happen, turn oven on fine, adjust menus etc... then once it starts heating up and pulling a high current it tripped out. When I went to have a look it was a a single strand I had missed that was poking out underneath rest of the cable. been very attentive with them since and crimping again.

 

[Stephen]

With those AEG ovens they use hex screws and unless you crimp the cable ends you have to split it around the screw. its very easy to get a loose strand that is sticking out touching the oven body. which is at earth potential and then trip the rcd. I have had it happen, turn oven on fine, adjust menus etc... then once it starts heating up and pulling a high current it tripped out. When I went to have a look it was a a single strand I had missed that was poking out underneath rest of the cable. been very attentive with them since and crimping again.

This could well be it you know. I remember it was tough and we made a few attempts with the wiring to split it around the screw neatly.

I will check that.

Thanks Gavin

 

['mr2'gd4u]

Yep,

quite common with the new metal accessories as they are just that bit wider than older plastic ones so if the back boxes are too close they over lap. i suspect the cause is that they have used dual backboxes so the socket and middle fcu are in same one, not enough space in middle for them, hence the over lap.

OP has already said that is was patresses used and an error on there part.

 

[SparkyChick]

This could well be it you know. I remember it was tough and we made a few attempts with the wiring to split it around the screw neatly.

I will check that.

Thanks Gavin

If it is that, I for one would still advise you get that junction box sorted sooner rather than later, particularly as it's easy to forget where such things are placed.

 

['mr2'gd4u]

I was wondering that?
maybe was a disagree because it shouldn’t have ever been buried as burying the joint effectively removes the safe zones to run the cable in?

I thought regulation stipulates that if its inaccessible it must be MF not that it must be accessible full stop, I agree joints behind plaster is less than ideal. I've never had to make a joint to be set behind plaster so be good to know...

 

[MFS Electrical]

I thought regulation stipulates that if its inaccessible it must be MF not that it must be accessible full stop, I agree joints behind plaster is less than ideal. I've never had to make a joint to be set behind plaster so be good to know...

Yeah I think a maintenance free box would be technically ok buried in plaster as long as it had good enough IP rating to prevent the plaster ending up in the box.
But if you remove the accessory that it used to be there then there is no indication that a cable and subsequently a junction Box are there Because by removing the accessory you have removed the thing that you “measure” the safe zones from if the accessory that you remove was say in line with another socket you’d be ok but in my experience those big ugly cooker switches tend to be mounted significantly higher than the sockets so you could end up with a cable running down the wall not in any safe zone.

 

['mr2'gd4u]

Yeah I think a maintenance free box would be ok buried in plaster as long as it had good IP rating to prevent the plaster ending up in the box.
But if you remove the accessory that it used to be there then there is no indication that a cable and subsequently a junction Box are there Because by removing the accessory you have removed the thing that you “measure” the safe zones from if the accessory that you remove was say in line with another socket you’d be ok but in my experience those big ugly cooker switches tend to be mounted significantly higher than the sockets so you could end up with a cable running down the wall not in any safe zone

Yea as I said I agree less than ideal, I suppose I depends how far it's being moved as well... 3" or 4" not so bad 12+"... Not sure why I got a disagree for it though @123

 

[MFS Electrical]

Yea as I said I agree less than ideal, I suppose I depends how far it's being moved as well... 3" or 4" not so bad 12+"... Not sure why I got a disagree for it though @123

There will be 101 better ways to do it like MF JB in the ceiling under the floor or even a screw type JB in the attic. Personally when I stick a JB anywhere even if it’s MF I like to make sure it can still be accessed even if there is no requirements for it to be I’ve seen “wago type” connectors either knock offs or other legitimate brands fail spectacularly, so even with MF it probably isn’t the best of ideas to make it totally inaccessible.