UK Gas Cooker conked and electrical cooker replacement

[advicewelcom]

I'll try again to explain.
it's not possible to say unless you know what size cable runs to the boiler spur, what size breaker it's on, and whether it's part of a ring serving other accessories as well, or is a radial circuit (ie one cable going from consumer unit to that fcu.), and if the latter you need to be sure of the current carrying capacity of the cable, and if it's serving anything else.

If you can answer the following, there might be a chance of deciding if it's practical. Otherwise you'll need an electrician to investigate and advise (which I recommend).

What markings are on the Hager breaker that serves the boiler fcu - in particular what current rating?
If there's a label below the breaker, what does it say (eg 'boiler!', or 'downstairs lights!')
Does anything else in the house go off if you switch off that boiler breaker (needs checking carefully)
Is it a single twin and earth cable that goes into the back of the boiler fcu, or are there two sets of cables?
Is the cable in the back of the boiler fcu the same physical size as the cable in the gas hob fcu (eg 2.5mm T&E)?

I made the suggestion to plug the washing machine into that socket, as a possible way of achieving the installation of the oven, because it avoided you having to interfere with the fixed installation. Now we are back playing with the house wiring, I think you would be better served getting an electrician in to solve the problem. He would see the best way of doing it, rather than us trying to divine it remotely.
However if you can answer the questions above, we might hazard a guess as to whether it could be a straightforward job for that electrician!

If you can answer the following, there might be a chance of deciding if it's practical. Otherwise you'll need an electrician to investigate and advise (which I recommend).

What markings are on the Hager breaker that serves the boiler fcu - in particular what current rating?
If there's a label below the breaker, what does it say (eg 'boiler!', or 'downstairs lights!')
Does anything else in the house go off if you switch off that boiler breaker (needs checking carefully)
Is it a single twin and earth cable that goes into the back of the boiler fcu, or are there two sets of cables?
Is the cable in the back of the boiler fcu the same physical size as the cable in the gas hob fcu (eg 2.5mm T&E)?

I made the suggestion to plug the washing machine into that socket, as a possible way of achieving the installation of the oven, because it avoided you having to interfere with the fixed installation. Now we are back playing with the house wiring, I think you would be better served getting an electrician in to solve the problem. He would see the best way of doing it, rather than us trying to divine it remotely.

Hi, thanks, will probs get elecy in, but is hard to find anyone and more chance if I can be specify exactly what the job is and some of the homework is done prior to them coming onsite.

Pic attached of the RCD/MCB box...

Diagram Marking 1 - Is for circuit 1 and is hager MTN 132 B32 - 32A
(Label says sockets but covers things in the kitchen already stated)

Diagram Marking 2 - is for circuit 2 and is hager MTN 120 B20 - 20A
(Label says "Boiler and Twin Sockets" - but the twin sockets next to boiler are actually on circuit 1 when tested).

Have hunted around and there aren't any other "twin sockets" for circuit 2 (would be great if there was) - assume for this purpose there isn't or anything else connected (other than the Hive which is powered from boiler)

Right fused spur pic shows approx wiring size and it seems like there is a wire coming from the twin socket side and also from the wall via top of the socket metal back box. Hence the twin sockets are on circuit 1? (follows from the socket testing).

Left fused spur has one wall wire coming in from the top of the socket metal box and one leaving the bottom of the fused spur casing to the boiler. Hive is connected to the boiler.


Would the quick solution be to connect that twin socket to the left fuse spur on circuit 2 and then plug the washing machine into that socket? Or is there an alternative if this isn't poss?

 

[Avo Mk8]

Hi,Would the quick solution be to connect that twin socket to the left fuse spur on circuit 2 and then plug the washing machine into that socket?

You seem to have a 20A radial with only the boiler on it, so basically "yes" !
As long as the 13A socket is safely taken out of the radial, and the ring is kept properly continuous after (eg Wago's)
Whoever does it needs to be competent!

 

[advicewelcom]

You seem to have a 20A radial with only the boiler on it, so basically "yes" !
As long as the 13A socket is safely taken out of the radial, and the ring is kept properly continuous after (eg Wago's)
Whoever does it needs to be competent!

Ok, hopefully I find someone, but if I can't, to take this on, I could...
-Turn both circuits off and test they are off with multimeter
-Pull out the wire connecting the twin sockets into the right fuse spur
-Connect it up to the left fuse spur in the same way
-Close everything up and test
-Plug washing machine into twin sockets
-Fit electrical oven

Not my preference to do myself, but cannot wait for someone to turn up if the oven has to be replaced. There are no gotcha's here or complications?

 

[DPG]

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

 

[Avo Mk8]

Ok, hopefully I find someone, but if I can't, to take this on, I could...
-Turn both circuits off and test they are off with multimeter
-Pull out the wire connecting the twin sockets into the right fuse spur
-Connect it up to the left fuse spur in the same way
-Close everything up and test
-Plug washing machine into twin sockets
-Fit electrical oven

Not my preference to do myself, but cannot wait for someone to turn up if the oven has to be replaced. There are no gotcha's here or complications?

Just to clarify - I misunderstood how the 13A socket was wired, sorry my error - you’re saying there is just a single cable going from it to the fused spur on the right?
In which case what you describe is a viable way of having it done.

 

[advicewelcom]

Just to clarify - I misunderstood how the 13A socket was wired, sorry my error - you’re saying there is just a single cable going from it to the fused spur on the right?
In which case what you describe is a viable way of having it done.

Yes, think so - I assume its a ring - so the wall power wire going to the right fuse spur (for the hob) and then cable going to the twin socket.

Hopefully I can open all the sockets up - if the right fuse spur is same as left spur - can wire that up to the twin sockets - then twin sockets will be on Circuit 2.

Job's a good 'un - can have turkey for Xmas.

... but stay tuned, as betcha something will throw spanner in works.

 

[advicewelcom]

Hi, took all the sockets apart and had a good look. Its like the attached diagram, with the right hand of the twin socket wired to the hob FCU.

I assume I can just wire it up with the red line to the Boiler FCU instead and then plug the washing machine into the left hand twin socket.

This will work okay considering the above?

 

[Avo Mk8]

Hi, took all the sockets apart and had a good look. Its like the attached diagram, with the right hand of the twin socket wired to the hob FCU.

I assume I can just wire it up with the red line to the Boiler FCU instead and then plug the washing machine into the left hand twin socket.

This will work okay considering the above?

What you've drawn as the original circuit in black, would be an unusual way for the house to be wired.
Also not quite sure what the red dotted line represents, you're not thinking each socket is wired independently? (they're not!).

I would expect a kitchen ring to be wired from one accessory to the next, so from 'fuse box' to twin socket, then to gas hob fcu, then to remainder of ring, and back to the 'fuse box'. ie no link where you have the word 'circuit'.
I know your sketch is only illustrative, but you have drawn cable "T junctions" in the middle of nowhere - they must be at an accessory, so think carefully about how it forms a 'ring'
Disconnecting as you show, I believe, would break the ring (because I think the horizontal black connection doesn't exist), so the modification would reduce the current carrying capacity of the circuit, become non-compliant with the regulations, and be dangerous.
Normally taking an accessory out of a ring requires re-joining the cables as they were, with Wago's etc, to main the continuity of the ring.

As has been said before, this forum is not supposed to give step by step advice for DIY. I'm explaining the above because I don't want you to create a dangerous situation.
Working on the fixed installation of a house requires certainty and competence in what is being done.
You have described earlier in general terms how to solve the issue you had.
Just make sure it's executed correctly.

I think it's best if I don't respond further.
Keep safe.

 

[advicewelcom]

Appreciate the contact and nearly there. Issues is current COVID stuff not able to get an elecy in with older people in the house and there is an turkey that needs roasting for Crimbo, so the clock is ticking on oven installation. Thus grateful for any feedback on the below...

---

...your right, it must be a ring (can disconnect and check), but that explains that wire from twin socket to the right hob FCU.

DIAGRAM ATTACHED.

If if connect up the ring with connector block and insulation tape (behind the socket) to completed the kitchen circuit.

Then add addition 2.5 T&E (RED line) to connect the twin socket to the boiler FCU.

2.5 T&E it's good for 26Amps to support the twin sockets. Then plug washing machine into that.

The fuse in the Boiler FCU has to be 13A?

.. Is that job done?

 

[brianmoooore]

The wiring arrangement in the diagram you posted above would be compliant.
If you end up with connections from two different circuits in the same enclosure, a warning label should be fitted.

 

[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??