Advice on consumer unit replacement.

[Davisonp]

Hi, I have an issue I cannot get my head round.

I have been asked to replace a consumer unit, and the circuits are run in steel conduit with singles for live and neutral and using the conduit as the earth for sockets and lighting. There is also an MICC cable supplying the cooker.

There are two conduit’s entering from the bottom of the CU, and one conduit from the top of the CU along with the MICC entry.

My problem is modern consumer units are taller than the old ones, and I don’t know if it is practice to cut and rethread steel conduit fixed in place and containing cables.

I would consider mounting the new consumer unit in front of the existing unit so the conduit and MICC does not need to be disturbed, but my worry is that once the new consumer unit is in place, the earthing for all circuits is only accessible by dismantling the current consumer unit.

Any Advice?

Regards
Ps Sorry about repeated images, but there is no way to remove an image if added by mistake and no way to reset the add new thread that I can find.

 

[telectrix]

as a suggestion, you could cut the existing CU casing down to about 35mm , leaving the existin back half with the conduits in it as a pattress to screw the new CU on top of. extend the cables with wagos. i'd recommend sa thourough testing esp. of the conduit as cpc.

 

[Davisonp]

as a suggestion, you could cut the existing CU casing down to about 35mm , leaving the existin back half with the conduits in it as a pattress to screw the new CU on top of. extend the cables with wagos. i'd recommend sa thourough testing esp. of the conduit as cpc.

Thank you,
Sounds like a plan although there is still the problem that the actual earthing connections are inaccessible being inside the pattress section.

 

[telectrix]

strap a fly lead from the pattress to the new CU case and to the earth bar.

 

[westward10]

No chance of getting one or two adaptable boxes in there ? Mind you I probably would not want to be undoing that MI gland. They look imperial those conduits, could improve it by fitting serrated washers.

 

[Harwoodandy]

Is there any space either side of the existing CU?

 

[The Ghost]

wow thats quite a challenge

 

[Davisonp]

Is there any space either side of the existing CU?

Not enough space above, below or beside it. I had thought of putting a panel over the front and putting the new unit elsewhere turning this into a junction box.

 

[Davisonp]

No chance of getting one or two adaptable boxes in there ? Mind you I probably would not want to be undoing that MI gland. They look imperial those conduits, could improve it by fitting serrated washers.

I had not even though about imperial fittings. I will defiantly be leaving the existing connections in place. My current though is to use self tapping screws to attach the new CU over the front of the existing CU and supporting it if required.

 

[westward10]

I have seen new boards fitted over old but the existing board is often flush. I would only fit over old one as a last resort, mainly because even though it will be safe it will look terrible.

 

[7029 dave]

deleted

 

[7029 dave]

I had not even though about imperial fittings. I will defiantly be leaving the existing connections in place. My current though is to use self tapping screws to attach the new CU over the front of the existing CU and supporting it if required.

That is not a bad idea, all cable entry's in the back, fly lead an earth from old to new. Shame there is no room at the side.

 

[Jon Barrett]

Hi, I have an issue I cannot get my head round.

I have been asked to replace a consumer unit, and the circuits are run in steel conduit with singles for live and neutral and using the conduit as the earth for sockets and lighting. There is also an MICC cable supplying the cooker.

There are two conduit’s entering from the bottom of the CU, and one conduit from the top of the CU along with the MICC entry.

My problem is modern consumer units are taller than the old ones, and I don’t know if it is practice to cut and rethread steel conduit fixed in place and containing cables.

I would consider mounting the new consumer unit in front of the existing unit so the conduit and MICC does not need to be disturbed, but my worry is that once the new consumer unit is in place, the earthing for all circuits is only accessible by dismantling the current consumer unit.

Any Advice?

Regards
Ps Sorry about repeated images, but there is no way to remove an image if added by mistake and no way to reset the add new thread that I can find.

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Hi, I have an issue I cannot get my head round.

I have been asked to replace a consumer unit, and the circuits are run in steel conduit with singles for live and neutral and using the conduit as the earth for sockets and lighting. There is also an MICC cable supplying the cooker.

There are two conduit’s entering from the bottom of the CU, and one conduit from the top of the CU along with the MICC entry.

My problem is modern consumer units are taller than the old ones, and I don’t know if it is practice to cut and rethread steel conduit fixed in place and containing cables.

I would consider mounting the new consumer unit in front of the existing unit so the conduit and MICC does not need to be disturbed, but my worry is that once the new consumer unit is in place, the earthing for all circuits is only accessible by dismantling the current consumer unit.

Any Advice?

Regards
Ps Sorry about repeated images, but there is no way to remove an image if added by mistake and no way to reset the add new thread that I can find.

View attachment 34021

View attachment 34022

View attachment 34023

View attachment 34024

View attachment 34025

View attachment 34026

View attachment 34027

View attachment 34028

 

[Jon Barrett]

Hello

With the new style metal consumer units it should not be too much of a problem. I see no reason why you can't thread the conduit in situ as long as you are careful. Good luck.

Jon

 

[Pete999]

Hello

With the new style metal consumer units it should not be too much of a problem. I see no reason why you can't thread the conduit in situ as long as you are careful. Good luck.

Jon

Thread the conduit in situ? would like to see how you would go about that.

 

[Octopus]

If I was asked to quote for that, I would put a very high price in ...... so that some other mug does it.

 

[7029 dave]

20mm Fast Fix Threadless Galvanized Conduit Accessories - http://cle-electrical.co.uk/20mm-fast-fix-threadless-galvanized-conduit-accessories

Maybe do something with this product, lose the old cu, drill out bottom of new cu, to take old conduit's. Top conduit, cut and use the threadless coupler to fit to size.

 

[amlu]

strip the old fuses, install a din rail in there, fabricate a fitting lid( from a new unit?), install set of new rcbo , job done...

 

[westward10]

20mm Fast Fix Threadless Galvanized Conduit Accessories - http://cle-electrical.co.uk/20mm-fast-fix-threadless-galvanized-conduit-accessories

Maybe do something with this product, lose the old cu, drill out bottom of new cu, to take old conduit's. Top conduit, cut and use the threadless coupler to fit to size.

They look imperial those conduits.

 

[7029 dave]

They look imperial those conduits.

Yeah I keep looking at them, Im not sure.

 

[westward10]

Yeah I keep looking at them, Im not sure.

I am certain, the MI is if you look at the sleeving. One of the bottom entry conduits appears to be terminated at an oversized entry. They also have lockouts locking the conduit to the couplers, that is definitely a method I haven't seen for years. State of those conduits though I would think a rewire is probably in order.

 

[7029 dave]

I am certain, the MI is if you look at the sleeving. One of the bottom entry conduits appears to be terminated at an oversized entry. They also have lockouts locking the conduit to the couplers, that is definitely a method I haven't seen for years. State of those conduits though I would think a rewire is probably in order.

Yes those lock nuts do give a clue.

 

[Davisonp]

If I was asked to quote for that, I would put a very high price in ...... so that some other mug does it.

I was the other mug. A little old lady that has been told by her sister that it looks dangerous and so she insists it is changed.

I tried an EICR hoping to be able to convince the lady that the installation is not significantly more dangerous than when installed, but found problems that mean I must recommend a CU change, although I actually believe it would be better to make a few minor repairs and not change the consumer unit.

 

[westward10]

I was the other mug. A little old lady that has been told by her sister that it looks dangerous and so she insists it is changed.

I tried an EICR hoping to be able to convince the lady that the installation is not significantly more dangerous than when installed, but found problems that mean I must recommend a CU change, although I actually believe it would be better to make a few minor repairs and not change the consumer unit.

What problems to suggest a CU change.

 

[Davisonp]

Yeah I keep looking at them, Im not sure.

I have a photo with a tape to get the box size, and using a photo editor, have tried to measure the top conduit. It is about 16mm, or exactly half an inch.

 

[westward10]

Looks like 5/8 conduit then in 3/4-5/8 reducers not lockouts.

 

[Davisonp]

What problems to suggest a CU change.

1) Prospective Fault Current too high for existing consumer unit

2) There is also a break in the ring, which if cannot be fixed, needs the ring to be turned into two 20A breakers.

 

[westward10]

1) Prospective Fault Current too high for existing consumer unit

2) There is also a break in the ring, which if cannot be fixed, needs the ring to be turned into two 20A breakers.

Fair enough.

 

[sparkdog]

I think I would do it properly & use the conduit.

 

[westward10]

I think I would do it properly & use the conduit.

Elaborate not sure what you mean.

 

[sparkdog]

Connect it same as the old cu with conduit @ pyro.

 

[westward10]

Connect it same as the old cu with conduit @ pyro.

That is the problem he can't find a CU which fits between the existing conduits.