Consumer Unit Replacement

Sponsored Links
Hi Guys

Almost there with my parts etc, just waiting for a die stock to arrive so I can put my M16 thread on my 5/8" conduit.
I was wondering about my consumer unit when I redo it so it has proper mating with the conduits etc about moving the tails entry to the left hand side of the consumer unit to a 32mm knock rather than the two 20mm knockouts he put them though on the bottom right of the CU.
As this is much closer to the meter and prevents the long lengths of the tails below the consumer unit. I would also use a plastic gland for protecting and fastening the tails and earth through the knock out.
To do this I thought it might be best to rearrange the dual pole switch isolator to the left of the CU, I assume this would be OK ?


I never knew about all this and the regulations but the more I look into it I find it hard to believe the guy could leave it like this as I could have got the bits he needed from the screwfix just up the road like I did with the heat shrink insulation.
 
I don't.

I'm afraid it's quite believable when people who aren't actually electricians take on work like this.

For a minute I thought you meant me.
I will get an Electrician to check it or maybe even do it but I want to work out a correct way to do it so when I ask him about it I can get an idea about him by his response.
 
Sponsored Links
I had a Electrician replace my old metal fusebox with a modern consumer unit I got from Screwfix and I am really not happy with what he did but once he started I had no option but to let him finish as I need an electric supply as I work at home via the internet.

Now my flat uses steel conduit as the earth and uses singles for the mains and lighting.

After yanking the old fusebox off the wall with a crowbar and pulling half the plaster off the wall and cutting all the insulation of the singles in the process. Hence the shrink wrap insulation on all the wires to repair it.
Forget about the nearly setting light to my flat with his dodgy extension lead which had a cut live wire in it and started sparking with flames coming out on my carpet. luckily his assistant picked it up and held it off the floor while he hurried to disconnect it.
What an absolute nightmare that was.

My main concern now is that my flat wiring is now not safe as the earth termination has been removed.

The conduit where he cut it with an angle grinder has very sharp edges and when I suggested deburring it he gave me a funny look. although after my insistence he did attempt to deburr them.


I am getting an inspection done and then have to rectify it but for now I have put earthing straps on the conduit.
I am going to have my flat rewired replacing the singles with twin and earth.

Surprising after all his work he refused to issue a certificate saying about the earthing and a mains ring being broken. If he had mentioned this problem to start with I would have told him to leave it while I look into what to do.
I am scared to get another Electrician into fix it now but I know I must.
 
Hi Guys

Almost there with my parts etc, just waiting for a die stock to arrive so I can put my M16 thread on my 5/8" conduit.
I was wondering about my consumer unit when I redo it so it has proper mating with the conduits etc about moving the tails entry to the left hand side of the consumer unit to a 32mm knock rather than the two 20mm knockouts he put them though on the bottom right of the CU.
As this is much closer to the meter and prevents the long lengths of the tails below the consumer unit. I would also use a plastic gland for protecting and fastening the tails and earth through the knock out.
To do this I thought it might be best to rearrange the dual pole switch isolator to the left of the CU, I assume this would be OK ?


I never knew about all this and the regulations but the more I look into it I find it hard to believe the guy could leave it like this as I could have got the bits he needed from the screwfix just up the road like I did with the heat shrink insulation.

I don't recommend moving the main switch to the other side.

Incidentally, the tails should be behind the din rail, not in front of it.

The tails should go through one hole in the metal work of the consumer unit.

I'd recommend a new consumer unit, as all the holes in it won't line up with the conduits. New holes need drilling.

Can't help wondering if the 'good bodge' idea I wrote earlier would be considerably cheaper, though I'd recommend additional single earth wires run in the cut conduits to the first accessory of each circuit, and at the same time replace the damaged red and black singles.

This would require to people feeding them in though, as the wires may get caught on any rough metal edges at each end.
 
Why not bite the bullet. Rewire with twin and earth and abandon and/or remove the conduit.

Who knows what damage may have been done to the red and blacks further into the conduit if the bodger was tugging at / twisting them during that horrendous "instalation" of a new consumer unit
 
sparkwright and bernardgreen, you both have good suggestions.
I definitely don't like all the bodged cables with tape or shrink wrap insulation in the CU and they need replacing for sure.

The flat wiring is a mess, as someone has added to it over the years and when taking a step back and looking at it all, I can see I can simplify by removing the use of some of the conduits.

of the top 4 smaller conduits which I label TC1 to TC4 going from left to right:-

TC1 feeds into the kitchen (via a bodged ceiling job) to a single dual socket K1B up high on the wall.
TC2 feeds into the kitchen (via the ceiling) to a single socket K1G which is used by the fridge
TC3 feeds into the kitchen (via the ceiling) to two dual sockets K1A & K1F
TC4 is the lighting circuit (only important one of the top 4)

the bottom two larger conduits which I label TC5 and TC6 are for the (broken) ring main which feeds the rest of the flat and two sockets in the kitchen K1D & K1E

My thoughts are that I only really need to keep TC4 which will mate correctly with the CU if it is moved up about 1 CM. The initial point the cables goto is the hallway rose which is very close, so I think it would be possible to pull through some 1.5mm2 T&E lighting cable.
Its worth a try at least and I got some yellow 77 cable lubricant which should help.
I can just abandon TC1 to TC3 as I will feed a separate ring to the kitchen to supply all the sockets via new conduit going down from the consumer unit using 2.5mm T&E cable.
I will also add another pair of conduit going down from the CU for the mains ring for the rest of the flat since going under the floorboards is not too painful, as I want to add more sockets to the ring anyway as the original of 1 or 2 a room is not enough these days.
I have also got plastic box conduit on the wall in the cupboard which is not shown for the boiler and thermostat plus I want to bring out 20VAC from the transformer for my doorbell.


I did buy a reel of 2.5mm yellow/green earth cable I was going to try and feed through.
 
By the way my die and stock arrived today and I managed to thread the conduit with an M16 thread and the 20mm to 16mm reducer fits snug on the end.


Not sure I need it now but it was an interesting exercise.
 
Remember you can re-use the old conduits futher down the circuits, so if you run t+e from the consumer unit to the first 'accessory', you can provide an earth link from the t+e to the metal back box, which will earth the conduits and back boxes thereafter (ASSUMING no one has messed about with it).

It seems most of the place needs rewiring anyway. Is this correct?

It would be very sensible to add an earth wire in all the conduits as it's more reliable IMO.

Conduit of your type is designed to be re-wired, that's the main point of it.
Running t+e through it may or may not provide awkward.

I do like the idea of repairing the old conduits, though there are alternatives though as you can see.

A 1.0 mm2 t+e would be sufficient to feed your lighting, and SHOULD pass through your conduit, though if you ARE able to make the conduit end good then singles may be the answer.
 
I guess I need to go around checking out each socket first of all and checking the conduit continuity between them to check out the overall state.
All this just because I wanted to put a bathroom fan in and I thought if I am getting someone in to do it I might as well get them to replace the consumer unit as well;)

After earth strapping the conduits around my CU I went ot check the earth on a socket and the first one I checked had a very high impedance, so I took the socket off and looked inside and it was a proper single socket with the conduit connected properly.
Then I remembered this one was a spare from a double socket so I took the cover off to discover 3 conduits about an inch away from the metal box and not connected.
So that was two sockets not earthed, so I lifted up the floor boards and put earth straps on all three and connected them all together bringing up an earth lead into the socket.
Then I tested this socket and the spur socket and the resistance back to the earth in the CU was 0.3 ohms which is OK but I guess it should be less.

I need to check the rest but its not easy with the little one around but next weekend my mrs is away with him at a friends house for the weekend so hopefully I can get on and test things and try and improve it.
With pulling cables I guess you need someone else to help feed in the cables while someone pulls them to reduce friction.

Maybe I will get 1.0 mm2 cable for the lighting as it will be a bit smaller and easier to pull through but i will try the 1.5 mm2 cable first since i got it.

The other problem I got is the main fusebox for the flats now has a padlock on it and the council will only give the key to an electrician with a company id, which is all very well and good and I understand why they do it.
But I think it will tempt others to try things live as getting the key is unbelievably hard and has to be booked at least a week in advance.
I would have thought as the flat owner I would have the right to the key or even my own key, but its only really a problem if want to tidy up the tails.
 
I guess I need to go around checking out each socket first of all and checking the conduit continuity between them to check out the overall state.
All this just because I wanted to put a bathroom fan in and I thought if I am getting someone in to do it I might as well get them to replace the consumer unit as well;)

After earth strapping the conduits around my CU I went ot check the earth on a socket and the first one I checked had a very high impedance, so I took the socket off and looked inside and it was a proper single socket with the conduit connected properly.
Then I remembered this one was a spare from a double socket so I took the cover off to discover 3 conduits about an inch away from the metal box and not connected.
So that was two sockets not earthed, so I lifted up the floor boards and put earth straps on all three and connected them all together bringing up an earth lead into the socket.
Then I tested this socket and the spur socket and the resistance back to the earth in the CU was 0.3 ohms which is OK but I guess it should be less.

I need to check the rest but its not easy with the little one around but next weekend my mrs is away with him at a friends house for the weekend so hopefully I can get on and test things and try and improve it.
With pulling cables I guess you need someone else to help feed in the cables while someone pulls them to reduce friction.

Maybe I will get 1.0 mm2 cable for the lighting as it will be a bit smaller and easier to pull through but i will try the 1.5 mm2 cable first since i got it.

The other problem I got is the main fusebox for the flats now has a padlock on it and the council will only give the key to an electrician with a company id, which is all very well and good and I understand why they do it.
But I think it will tempt others to try things live as getting the key is unbelievably hard and has to be booked at least a week in advance.
I would have thought as the flat owner I would have the right to the key or even my own key, but its only really a problem if want to tidy up the tails.
Get an up front isolator fitted before your cu, then you can isolate whenever you like.
 
0.05 is a better figure. You need to scrape/ abrade the conduit to expose bare metal. This will give the earth strap a much better connection, hence a lower resistance.
 
Get an up front isolator fitted before your cu, then you can isolate whenever you like.

Yes I did think about that.
The guy broke the seal on my electricity meter so he could remove the tails from it to isolate the CU.
Does this mean I will get in trouble from the electricity company as they may think I have been up to no good ?
 
Your place sounds like a can of worms, everything needs checking.

When you fitted earth straps to the conduits, did you remove the rust and paint first?
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Back
Top