Consumer unit extension wiring

muso31 · Jun 23, 2023

Hi all! I'm not a spark but know enough to be able to install off grid solar etc. I've just purchased a new house and have noticed the consumer unit was extended at some point:

[ElectriciansForums.net] Consumer unit extension wiring

The additional unit is from the kitchen as they had a new kitchen fitted. My concerns are with the quality of the work. No glands are used and all wiring enters the side, the cables also have sheathing cut short so the wires are exposed. I'd have thought some simple chaffing could expose a wire and short the consumer unit:

Due to these concerns I opened up the box to take a look at the method used to extend the wires:

I have a few questions here... why are glands not used? Is it ok not to use a DIN rail and simply extend all circuits with lever terminals? If so, would splice connectors 221-2411 not be more suitable? If the cables aren't long enough to reach a DIN rail, would it be best to use a Wiska Consumer Unit Relocator for any circuits that do have a wire long enough, and then extend the others?

I'm assuming this is legal, but sloppy work.

nicebutdim · Jun 23, 2023

It's rough but, provided connectors are able to handle the rated current of each outgoing circuit, there's no real issue on that front.

Cables should indeed be restrained and IP rating of enclosures maintained. The main issue, as you've highlighted, is cable sheaths and exposed insulation entering through a cut metal edge. There are a number of ways this could be resolved and glanding individual cables is one of them. To make the best of what you have, I'd probably replace the 2 gang surface box with a small adaptable box and run a short length of 2x2" PVC trunking between it and the board, which would provide space to place some sort of gromment over that cable entry.

I'd be slightly concerned about what's inside your CU, but it may all be fine.

westward10 · Jun 23, 2023

Those Wagos are poorly connected, far too much insulation stripped from them. The bottom one appears to have two cpcs in the same sleeve into one terminal. It doesn't bode well for what the consumer unit contains.

nicebutdim · Jun 23, 2023

westward10 said:
Those Wagos are poorly connected, far too much insulation stripped from them. The bottom one appears to have two cpcs in the same sleeve into one terminal. It doesn't bode well for what the consumer unit contains.

You win tonight's best eyesight award!

telectrix · Jun 24, 2023

Cut that box the get the cables out without dissing the wagos. Replace with a Wago XL box, which has cable restraint built in. Then tidy up the connections 1 at a time. Be nice to see a pic. of the CU wiring.

mattg4321 · Jun 24, 2023

As soon as I see a BG board I always think the worst!

muso31 · Jun 24, 2023

Cheers all, I like the idea of a Wago XL box - I'll have to check if the original cables are long enough to reach a box as they seem to be quite short.

Here's the CU:

Seems ok although not the neatest and the grommet looks cross threaded:

What was slightly alarming was the lack of sheathing on an earth cable in the side entry:

I've put a sheathing on it for now as a temporary measure until its sorted properly. As I unscrewed it, it was pretty chewed up where it joined the earth bar also:

I'll look into replacing the surface box based upon how long the cables are...

timhoward · Jun 24, 2023

I hate to say it, but looking at that chewed up earth, I fear every terminal was tightened with an impact driver. At an absolute minimum I'd turn the power off and look at the other CPC's (earth wires). If required trim them so you are biting on undamaged copper and loop the end around (similar to how the Neutral's are) so you get a better connection.

SJD · Jun 24, 2023

You would normally put the two lighting circuits on separate RCDs, so one RCD tripping doesn't plunge the whole house into darkness. But it could be done this way because of a borrowed neutral e.g. the landing light (L supplied from downstairs, N to upstairs) and they couldn't be bothered to fix that.

Risteard · Jun 24, 2023

SJD said:
You would normally put the two lighting circuits on separate RCDs, so one RCD tripping doesn't plunge the whole house into darkness. But it could be done this way because of a borrowed neutral e.g. the landing light (L supplied from downstairs, N to upstairs) and they couldn't be bothered to fix that.

A borrowed neutral is required to be on one circuit rather than just one RCD though for safety reasons (which of course would no longer render it a borrowed neutral).

lozarus · Jun 24, 2023

Anyone else noticed what seems to be doorbell wire in the 2 gange encloolsure at the bottom? Band 1 & Band 2 conductors mixed.

Admittedley probably least of the issues but still.

LewisM · Jun 24, 2023

How can you have all that room with a new board and cables entering the one place and it still look that bad!

muso31 · Jun 24, 2023

Confirmed that the doorbell doesn't work. I was going to add a bell transformer at some point

Dustydazzler · Jun 24, 2023

mattg4321 said:
As soon as I see a BG board I always think the worst!

Its not know as a the rough older Builders board of choice for nothing

muso31 · Jun 24, 2023

Pretty grim. I've spent time on it today to put new cables in and glands:

Still not perfect but have addressed the side entry issues. Unfortunately the cables aren't long enough to allow the Wago junction box to be used correctly, what's the best way to resolve this, if any?

telectrix · Jun 24, 2023

mattg4321 said:
As soon as I see a BG board I always think the worst!

me installed loads of BG boards. bever a problem. just hate the newer busbar shrouds.

freddo · Jun 25, 2023

I haven't installed a dual RCD board in years, RCBOs are so cheap now it doesn't really make sense to use them! I always hated the tangle of slightly too short internal tails as well.

timhoward · Jun 25, 2023

muso31 said:
Unfortunately the cables aren't long enough to allow the Wago junction box to be used correctly, what's the best way to resolve this, if any?

Without seeing it for myself this is a bit of a guess, but I'd probably grab a 20mm holesaw and make three or four holes holes is the back of the top of the Wago XL box near the top, mark everything with a Sharpie and then feed the short original wires through the back of the box, resulting in the short wires being nearer the top, and the box being mounted lower down.
When done you should fit cable ties so no one can easily unclip the front.

EDIT you may have to flip 180 degrees so the wago's are at the bottom, and the new cables enter at the top

muso31 · Jun 25, 2023

Either of these will work, great suggestions thanks

muso31 · Jun 25, 2023

Out of interest, if I ever upgraded to rcbo's, I'm assuming these are all single pole aside from the 'sockets first floor' because I've found this is actually incorrectly labeled and it's actually sockets for both floors with two cables entering the one mcb. Therefore it'd require a double pole rcbo?

...or is it simply wired like that as its a ring and not a radial, therefore still a single pole rcbo

loz2754 · Jun 25, 2023

A double pole RCBO is one that switches both the line and neutral conductors. It is not for switching 2 different circuits!!

The sockets circuit in your consumer unit has 2 cables because it is likely a ring final circuit.

vwes59 · Jul 29, 2023

Just an observation, but you are aware as a non-spark you're not supposed to be working on a consumer unit ? If something went wrong and traced back to the CU your house insurance company could have an issue with it, let alone buildings control as its notifiable work - Just an observation, I'm surprised no one else has picked up on that in the first post.

mainline · Aug 16, 2023

vwes59 said:
Just an observation, but you are aware as a non-spark you're not supposed to be working on a consumer unit ? If something went wrong and traced back to the CU your house insurance company could have an issue with it, let alone buildings control as its notifiable work - Just an observation, I'm surprised no one else has picked up on that in the first post.

Looks like he’s more competent than the one that did it originally.

muso31 · Aug 16, 2023

I'll be able to sign off domestic installs imminently. Seeing the level of workmanship drove me to study the level 3 etc. The consumer unit is now all sorted and the junction box is completely removed, alls the original installer had to do was move the consumer unit down a foot to make the original wiring long enough

With the removal of the unrequired joins/extensions, and with rcbos and an spd introduced alongside properly 'torqued' connections I'm a lot more comfortable with the installation.