UK Gas Cooker conked and electrical cooker replacement

[advicewelcom]

Oh poo. RCD flipped off and is not switching back on. I can put things to what they were before and try it, but if RCD stays off, any ideas?

 

[DPG]

Are the 2 circuits fed from different RCDs?

 

[advicewelcom]

Pic of the one RCD with Boiler Radial and Kitchen circuit off.


RCD failed when removing the twin socket and re-connecting the kitchen circuit (pics in next posting). I don't think it would reset even when I turned the Boiler and Kitchen circuit off (but that could be me not pressing it hard enough to reset it).

 

[advicewelcom]

Before & after pics attached of wiring adjustments when RCD went off.



PIC 1. BEFORE circuit before changes
-Boiler radial circuit (pretty sure only boiler)
-Twin sockets on ring to HOB FCU and to other kitchen sockets
-Switched HOB FCU has supply, connections to HOB and back to ring (3 wires)
-Noted that the earths on Twin socket are on different ends
-Pretty sure this IS a kitchen ring as tested it


PIC 2. AFTER circuit changes
-Just connected the kitchen circuit ring up without twin sockets


Why did RCD go off?

If you connect the earths together does the RCD go pop? Just don't get it.

 

[Avo Mk8]

If you connect the earths together does the RCD go pop? Just don't get it.

I said I wouldn't
The twin socket presumably has the two earth terminals visibly strapped together?

I don't immediately see the electrical difference between the two configurations you show. I don't get it either!

You know the RCD will stay tripped if N & E somehow get connected together, even when the two MCB's you are using are off?

You might try lifting the N feed to the boiler (with it off!) just to make sure another fault hasn't appeared in the meantine, and see if you can reset the RCD.

And finally, you haven't connected the cooker in the meantime by any chance have you? If so that's another avenue!

 

[advicewelcom]

I said I wouldn't

Was your idea to plug the washing machine to the twin socket, your on the hook at the moment ;-)

The twin socket presumably has the two earth terminals visibly strapped together?

OK, well I think that means they are connected within the socket and defo not the source of the issue.

I don't immediately see the electrical difference between the two configurations you show. I don't get it either! You know the RCD will stay tripped if N & E somehow get connected together, even when the two MCB's you are using are off?

Ah Ok, could be a short between N and E then eh? I could try taking off the twin socket only (not messing with the other sockets) and trying again with the terminal block connector and see if I get the same result. I only realised the RCD tripped when someone mentioned the upstairs sockets were off - so it wasn't really event driven by me turning something on - just seemed to quietly happen by itself.

You might try lifting the N feed to the boiler (with it off!) just to make sure another fault hasn't appeared in the meantine, and see if you can reset the RCD.

I heard that lots of RCD un-correctable trips are due to boiler connections. It an old boiler so it could be something loose. You're saying to pull off the neutral on the boiler FCU connection and see if that stops tripping when using the terminal connection block to by-pass the twin sockets?

I did think I saw a 5v AC reading across the terminals of the boiler FCU even when everything was off (which was a bit weird) - pic attached.

Even if I got it working - I would have a twin socket into the boiler FCU, and would the current 3A fuse in the boiler FCU have to be replaced with a 13A fuse as it now has twin socket connected with a washing machine plugged in? Is that going to create an issue? That FCU fuse is pretty vital, it blows, no heating during winter.

And finally, you haven't connected the cooker in the meantime by any chance have you? If so that's another avenue!

The oven is always connected and has never tripped anything else, The grill on it works fine and the issue is the gas thermostat knob, but I could switch it off from its wall FCU to rule it out when testing.

 

[Avo Mk8]

Ah Ok, could be a short between N and E then eh? I could try taking off the twin socket only (not messing with the other sockets) and trying again with the terminal block connector and see if I get the same result. I only realised the RCD tripped when someone mentioned the upstairs sockets were off - so it wasn't really event driven by me turning something on - just seemed to quietly happen by itself.

If you inadvertently touched N & E together while doing the changes, that would likely have tripped the RCD. That's normal behaviour and in itself nothing to worry about. But you give the impression you couldn't then reset the RCD, which implied there might be a further problem. If you can reset the RCD, and it stays reset, all should be all OK.

You're saying to pull off the neutral on the boiler FCU connection and see if that stops tripping when using the terminal connection block to by-pass the twin sockets?"

yes

I did think I saw a 5v AC reading across the terminals of the boiler FCU even when everything was off (which was a bit weird) - pic attached.

Probably a capacitatively coupled voltage from the house wiring, and since the meter is high impedance, it gives a reading. Once you put any sort of load on, it would disappear. You see this mentioned on this forum sometimes.

Even if I got it working - I would have a twin socket into the boiler FCU, and would the current 3A fuse in the boiler FCU have to be replaced with a 13A fuse as it now has twin socket connected with a washing machine plugged in? Is that going to create an issue? That FCU fuse is pretty vital, it blows, no heating during winter.

You're confusing yourself! You have a 20A radial from the 'fuse board' which you should connect directly to both the twin socket and the input to the fcu. Do not connect the twin socket to the boiler side of the fcu!

You don't need to change the fuse, leave as is.

The oven is always connected and has never tripped anything else, The grill on it works fine and the issue is the gas thermostat knob, but I could switch it off from its wall FCU to rule it out when testing.

Sorry I was meaning if you had bought a new electric oven and connected it. They occasionally cause this sort of problem. Ignore this.

Hope you sort it.

 

[marconi]

Good morning. MAy I ask some questions please?

1. Does the rcd trip when the washing machine is unplugged?

2. How, step by step, do you re-apply power? eg: all mcbs and RCD are on and i use the red main switch. Or. the main switch is on as are all the mcbs and I use the RCD. Or, the two mcbs in question are off and the RCD is off, the main switch is on and I then I turn on the RCD. Or, MAin switch is on, RCD and two mcbs are both off, and then I turn on the RCD and then the 20A mcb and then the 32A mcb?

3. Turn off red main switch and then CArefully remove lid of the consumer unit and take a photo of the wiring top and bottom of the RCD and then put the lid back on. DO NOT PUT YOUR FINGERS INSIDE!!!

4. With your multimeter set to the highest ac voltage range measure the voltages between:

a. earth of left hand FCU and the earth of the double socket to its right.

b. earth of the double socket and the securing screw of the FCU which switches the socket below for WM.

5. With Main Sswitch Off and your MM set to low ohms setting measure the resistance between:

b. earth of LH FCU and boiler pipes.

c. boiler pipes and a securing screw of the FCU which switches the socket for washing machine.

d. the securing screw of the FCU and a securing screw of the socket for the washing machine.

e. Between the pins of the plug of the washing machine L-N, L-E and N-E.

 

[advicewelcom]

Good morning. MAy I ask some questions please?

1. Does the rcd trip when the washing machine is unplugged?

Hi, yes, the washing machine was off and out of the twin socket when changing the wiring. I suspect this is me being careless with the N and E as mentioned before, but I have to go in with a testing approach (hopefully today) to try again.

2. How, step by step, do you re-apply power? eg: all mcbs and RCD are on and i use the red main switch. Or. the main switch is on as are all the mcbs and I use the RCD. Or, the two mcbs in question are off and the RCD is off, the main switch is on and I then I turn on the RCD. Or, MAin switch is on, RCD and two mcbs are both off, and then I turn on the RCD and then the 20A mcb and then the 32A mcb?

Will be mindful of this on the 2nd testing, but the last time

• Main switch was on
• RCD was on
• Two circuits for boiler and kitchen ring were off

Did was wiring changes, then was told sockets were not working upstairs - went to check and found the RCD tripped and unable to reset until I changed the wiring back to what it was before.

3. Turn off red main switch and then CArefully remove lid of the consumer unit and take a photo of the wiring top and bottom of the RCD and then put the lid back on. DO NOT PUT YOUR FINGERS INSIDE!!!

Okay - should be able to do that, bit tricky to get the cover off, but can do it carefully, understand there is live connections via the tails (I think) so not touch anything inside.

With the below I assume u mean the securing screw of the wire inside and not the silver securing screws of the socket visible outside.

4. With your multimeter set to the highest ac voltage range measure the voltages between:

a. earth of left hand FCU and the earth of the double socket to its right.

OK - V's between Boiler FCU Earth to double socket Earth

b. earth of the double socket and the securing screw of the FCU which switches the socket below for WM.

*There isn't a FCU for the WM twin socket? - I think you mean Volts across Twin socket Earth to HOB FCU Earth (pic attached)

5. With Main Sswitch Off and your MM set to low ohms setting measure the resistance between:

b. earth of LH FCU and boiler pipes.

Ok - Ω's between Boiler FCU Earth to Boiler pipes

c. boiler pipes and a securing screw of the FCU which switches the socket for washing machine.

OK - Ω's between Boiler pipes and Twin socket Earth (I assume)

d. the securing screw of the FCU and a securing screw of the socket for the washing machine.

OK - Ω's between HOB FCU Earth and Twin Socket Earth

e. Between the pins of the plug of the washing machine L-N, L-E and N-E.

OK - Ω's between washing machine plug pins L-N, L-E, N-E


*Welcome to clarify the above.

Can add this approach to the general test strategy if I have the same problems when trying again with the wiring.

 

[advicewelcom]

You're confusing yourself! You have a 20A radial from the 'fuse board' which you should connect directly to both the twin socket and the input to the fcu. Do not connect the twin socket to the boiler side of the fcu!

Just have to clarify this (PANIC STATIONS).

You are saying to connect from the Boiler FCU supply input to the TWIN SOCKET?

Think you're saying don't connect from the FCU output going to the boiler.

Attached a diagram of potential new wiring - is this correct? - wire from the Twin socket into the Boiler FCU Live, Neutral & Earth Supply connections??

And terminal block connect the incoming 32A ring supply to the HOB FCU??

 

[DPG]

This really does need an electrician getting in.

 

[advicewelcom]

This really does need an electrician getting in.

Try getting one, and then try dealing with the risks with virus in the household. I think I will have get elecy if it keeps tripping out. But will try the below first...


GENERAL TEST APPROACH
-Do wiring again and careful of N & E shorts
-Check the RCD
-If tripping lift Boiler FCU Neutral to boiler and see if can reset RCD

If still have tripping issues:
-Check whats going off and how in fuseboard
-Take photo of fuseboard circuit
-Do some MM testing with fuseboard



... seem ok?

 

[marconi]

OK - V's between Boiler FCU Earth to double socket Earth

The fact that you measure a voltage albeit small between the earth conductor of the boiler fcu and the earth conductor of the double socket on the right indicates a break in continuity of an earth conductor (more correctly circuit protective conductor cpc). This fault could be on the ring or on the radial to fcu or both. If the cpc between the fcu and the consumer unit and the cpcs of the ring back to the cu where complete and connected correctly then no voltage can exist between the boiler and double socket cpcs because they are effectively joined together. This state of affairs can cause an rcd to trip.

Time to call in a sparks with the right test equipment.

You can forget about taking the lid off the cu.

 

[advicewelcom]

OK - V's between Boiler FCU Earth to double socket Earth

The fact that you measure a voltage albeit small between the earth conductor of the boiler fcu and the earth conductor of the double socket on the right indicates a break in continuity of an earth conductor (more correctly circuit protective conductor cpc). This fault could be on the ring or on the radial to fcu or both. If the cpc between the fcu and the consumer unit and the cpcs of the ring back to the cu where complete and connected correctly then no voltage can exist between the boiler and double socket cpcs because they are effectively joined together. This state of affairs can cause an rcd to trip.

Haven't measured anything yet, assume this Earth to Earth V measurement test is to be done before any wiring changes to the Boiler radial and Kitchen Ring (seperate circuits) - and should come back with a 0v if there is no break in continuity.

 

[Avo Mk8]

Just have to clarify this (PANIC STATIONS).

You are saying to connect from the Boiler FCU supply input to the TWIN SOCKET?

Think you're saying don't connect from the FCU output going to the boiler.

Attached a diagram of potential new wiring - is this correct? - wire from the Twin socket into the Boiler FCU Live, Neutral & Earth Supply connections??

And terminal block connect the incoming 32A ring supply to the HOB FCU??

Yes. The 20A circuit is a 'radial', and you can feed multiple accessories (within reason) by daisy-chaining them. It's not the same as a ring.
So you connect the twin socket to the 2.5mm cable going into the boiler fcu, not the fused output of the fcu.
Live coming into fcu goes to live of twin socket, etc.

And then that fcu is left feeding the boiler exactly as it was before, same fuse, unchanged wiring on the output.

 

[brianmoooore]

Do we know if the boiler spur circuit is RCD protected?

 

[advicewelcom]

Do we know if the boiler spur circuit is RCD protected?

Yes, RCD off and no supply goes to boiler.

 

[DPG]

Yes, RCD off and no supply goes to boiler.

Are the circuits in question protected by an RCD though?

 

[advicewelcom]

If you have a bit of spare 3 core wiring in which the earth does not have a sleeve, is that okay to use to connect the twin socket to the boiler FCU?

 

[westward10]

As already stated whilst forum is happy to help the DIYer it has to draw the line at step by step guidance. This task is way out of your comfort zone and the pic in #51 demonstrates this because the back box with the block connectors floating about in it is no longer earthed. Because you have interfered with the existing wiring you now have an rcd tripping with no idea as to why so I suggest you reinstate what you have altered and call an electrician.

 

[advicewelcom]

As already stated whilst forum is happy to help the DIYer it has to draw the line at step by step guidance. This task is way out of your comfort zone and the pic in #51 demonstrates this because the back box with the block connectors floating about in it is no longer earthed. Because you have interfered with the existing wiring you now have an rcd tripping with no idea as to why so I suggest you reinstate what you have altered and call an electrician.

Needs must, there is a pandemic on and not allowed to bring others in, moreover its turkey time soon.

Not sure your analysis is on the mark as rewired it with a bit of 3core and RCD was fine. I suspect the Neutral and Earth were touched in first attempt (which I understand trips RCD).

(PIC ATTACHED) It don't look pretty, I assume I need a bit of neutral sleeving, perhaps wrap the terminal block up in insulation tape, and feed the connecting wire through the back box hole instead?

Just hoping its connected okay and experts on this group are happy with it - as have an oven to order. So very happy and thankful if its gets a thumbs up with any changes needed?

 

[westward10]

That box is not earthed. It would be unwise to advise you further you need an electrician covid or not to assess your situation.

 

[advicewelcom]

That box is not earthed. It would be unwise to advise you further you need an electrician covid or not to assess your situation.

Dying of Covid is nothing we can do about on this forum, dying from electrical shock is ;-) Good suggestion, I can fit a fly lead but looks like its been discussed quite a bit and seems not required by the regs as earthing happens through the lug for recessed back boxes (@ 2:22). Looks more applicable for surface mounted boxes.

 

[telectrix]

Dying of Covid is nothing we can do about on this forum, dying from electrical shock is ;-) Good suggestion, I can fit a fly lead but looks like its been discussed quite a bit and seems not required by the regs as earthing happens through the lug for recessed back boxes (@ 2:22). Looks more applicable for surface mounted boxes.

earthing back boxes was made optional around 2005 under the 16th.however, most of us prefer to earth them for the simple reson that if the faceplate is removed for any reason, you lose the earth through the faceplate oins so the back box could become live if a fault developed.

 

[westward10]

earthing back boxes was made optional around 2005 under the 16th.however, most of us prefer to earth them for the simple reson that if the faceplate is removed for any reason, you lose the earth through the faceplate oins so the back box could become live if a fault developed.

It looks like it is going to be blanked hence it needs an earth. Many electrcians to the exact same thing.

 

[nicebutdim]

Dying of Covid is nothing we can do about on this forum, dying from electrical shock is ;-) Good suggestion, I can fit a fly lead but looks like its been discussed quite a bit and seems not required by the regs as earthing happens through the lug for recessed back boxes (@ 2:22). Looks more applicable for surface mounted boxes.

Remember that old adage about 'a little knowledge'.

 

[Deleted account]

Surely this needs an electrician in. It's very close to step-by-step instructions on reconfiguring a circuit.

I think the above post needs seeing again.

 

[advicewelcom]

Thanks for past advice. Washing machine ordered for tomorrow (does not come with a wire) and assume there is calculation for a 2.3KW oven to determine the wiring requirement (2.5mm T&E would do the job I assume for 10A)?

Also those darn screws are not going into the backbox lugs easily and holding the front socket in, not sure if this is another newbie question - but if the back box is a bit warped is the suggestion to re-tap the lug thread or use something to fix it (removing the backbox would be a headache).

 

[brianmoooore]

Most domestic sparkies carry a 3.5mm thread cleaning/reforming tool in their toolbox.

 

[advicewelcom]

Most domestic sparkies carry a 3.5mm thread cleaning/reforming tool in their toolbox.

Ta - figured as much.

Almost there, just a query about lead installation from oven to wall FCU...
-2300W / 230v = 10Amps current expected through the electric oven lead at max.
-Understand that 2.5mm T&E does 24Amps circa (but not sure about unburied).
-Fuse in FCU would need to be 13Amps

If I have some spare 2.5mm T&E - this going to be okay for unburied oven lead to FCU?

Should I go for 4mm if unburied?

(BEKO manuals are flippin' useless and googlin is ambiguous).

 

[brianmoooore]

Will the temperature around the cable reach or exceed 70 degrees at any point?

 

[telectrix]

Ta - figured as much.

Almost there, just a query about lead installation from oven to wall FCU...
-2300W / 230v = 10Amps current expected through the electric oven lead at max.
-Understand that 2.5mm T&E does 24Amps circa (but not sure about unburied).
-Fuse in FCU would need to be 13Amps

If I have some spare 2.5mm T&E - this going to be okay for unburied oven lead to FCU?

Should I go for 4mm if unburied?

(BEKO manuals are flippin' useless and googlin is ambiguous).

2.5mm cable will be fine.

 

[advicewelcom]

Will the temperature around the cable reach or exceed 70 degrees at any point?

Oh, Dunno.. is a standard 60cm x 60xm x 60cm oven space, so assume not.

https://bekoplc.blob.core.windows.net/bekoupload/manuals/BBIF22300.pdf

2.5mm will be okay I think, if you violently disagree welcome hearing back.

 

[westward10]

How are going to terminate this 2.5 cable from the FCU.

 

[brianmoooore]

2.5mm2 will be fine. It's 2.5mm2 what that matters. I wouldn't be using 6242Y

 

[DPG]

Be interesting if it's coming out of the front flex outlet of an FCU !

 

[advicewelcom]

Be interesting if it's coming out of the front flex outlet of an FCU !

Oven Wiring - https://photos.app.goo.gl/7QLDMB6tawSqNdtB8

Switched FCU's under counter next to gas plumbing - one for hob (I assume) other on right side for current gas oven.

 

[westward10]

Oven Wiring - https://photos.app.goo.gl/7QLDMB6tawSqNdtB8

Switched FCU's under counter next to gas plumbing - one for hob (I assume) other on right side for current gas oven.

So how are you going to connect this 2.5 cable.

 

[advicewelcom]

Hi, its all fitted a looks great. So thanks a lot for past advice(!)

Was a bit worried about the power wire on the back touching the oven when pushing it in.

But so far, no issues with it, or with any of the circuits tripping.

 

[advicewelcom]

Did have another issue which someone on here may have an idea about?

The gas man who sealed off the connection said that was a small leak on the mains pipe that feeds the meter. He stuck some fairy liquid on it and there was a small bubble. I called Cadent who (after 4 hrs of messing around) changed the external pipping to the meter with some engineers during the evening.

The Cadent engineer then said there was a 2millibar drop showing and despite checking all the appliances with his sniffer (boiler, cut off gas seal for new oven, gas heaters, etc). cut off the gas on Christmas eve. I was horrified as there was no heating (even if the oven was working) on Crimbo day.

Does anyone know if they are allowed to cut the gas like this to a residential house when there has been no reported smell of gas, all appliances have been tested and the millibar drop on a tightness test is only showing 2millibar??

 

[James]

By the sounds of it they had to turn the gas off to repair something to do with the meter or the supply to it.

they will not be able to turn the gas to the property back on if there is a leak, unfortunately you are going to need the services of a gas safe registered plumber to find and repair the fault(s) within your house.

 

[advicewelcom]

By the sounds of it they had to turn the gas off to repair something to do with the meter or the supply to it.

Yes, correct, in fact they used some balloon thing to stop the gas coming out before the shut out valve, so they could replace the shut of valve with a new one.

they will not be able to turn the gas to the property back on if there is a leak, unfortunately you are going to need the services of a gas safe registered plumber to find and repair the fault(s) within your house.

Apparently suppliers (British Gas) etc accept small leaks as long as there is no smell of gas (I think 8millibars depending on the meter in the house) - Cadent have permittable levels of a small gas leaks (as long as there is no smell of gas) as well, but in this instance they seem to have ignored their own operation procedures and just capped off all the gas to the house.

At the beginning the engineer kept blaming me by saying I reported a "smell of gas" which I did not (it was the fairy liquid around the shut of valve that alerted to the minor leak around the shut of valve) not any smell - and they could have listened to the call in to verify that. The shut of valve is high up in the garage and its so well ventilated it would have been impossible to smell any minor gas around that area in anycase.

I think its got something to do with them passing the buck to someone else to re-open the gas so they can escape any blame. Was a horrible thing to do at that time. Is there some recourse to this action if its not in line with their operating protocols?

 

[James]

I think a chat with a good independent gas fitter would be the best place to start.
they are going to be in a far better position to advise than a bunch of electricians.

 

[advicewelcom]

I think a chat with a good independent gas fitter would be the best place to start.
they are going to be in a far better position to advise than a bunch of electricians.

Got the gas turned back already by calling out an independent gas engineer (he was shocked by what they did as well).

Just was curious if anyone in this forum knew about the dark arts of Cadent. There was massive consequences to them cutting gas off on Christmas eve when there are elderly and vulnerable people in the house that could not stay at other people's houses due to Covid risks - and have no heating, no hob, no hot water. Terrible thing for them to do and think I should pursue it - so it does not happen to anyone else.

 

[Deleted account]

I know Gas suppliers have more powers than The police in gaining entry to turn off gas in an emergency. So they can turn off your gas if it’s not deemed safe.

the supplier was correct not to turn on the gas until such time as the installationnwas deemed safe. They have a duty of care.

We electricians do not hav3 the power to turn off anyone’s electrics even if we think it’s dangerous.
However if we turn the power off to do some testing or a job and find the installation is unsafe, we cannot turn the power back on until such time as it is made safe.

so7nds like the same thing really, but it’s not.

 

[DPG]

Got the gas turned back already by calling out an independent gas engineer (he was shocked by what they did as well).

Just was curious if anyone in this forum knew about the dark arts of Cadent. There was massive consequences to them cutting gas off on Christmas eve when there are elderly and vulnerable people in the house that could not stay at other people's houses due to Covid risks - and have no heating, no hob, no hot water. Terrible thing for them to do and think I should pursue it - so it does not happen to anyone else.

Difficult to say without knowing the full story, but imagine the headlines if they switched the supply back on when there was a leak, and something went wrong.

 

[Deleted account]

Terrible thing for them to do and think I should pursue it - so it does not happen to anyone else.

It would have been a terrible thing to put you and the household at risk. Pursuing this would be a waste of time as the engineers will be backed up all the way on this one.

He was protecting you and did what was in the best interests of anyone within the house.

 

[westward10]

Difficult to say without knowing the full story, but imagine the headlines if they switched the supply back on when there was a leak, and something went wrong.

Like poor electrical connections

 

[advicewelcom]

"Safe" is ambiguous, so there is an Operating manual which was ignored.

 

[nicebutdim]

"Safe" is ambiguous, so there is an Operating manual which was ignored.

I'm not sure there's much mileage in arguing this point on a forum for electricians.