Cable routing inside a consumer unit

Andy Hames · Feb 1, 2023

Hi

First post and I'm a DIY-er so apologies if this is the wrong forum to start with.

I have a project at the moment that involves replacing a consumer unit. I've arranged for a proper inspection and certification down the line but in the mean time I have made a start on getting the circuits wired in where I can.

This is where I'm up to so far:

and this shows better how the wiring is routed:

I know some of the sheathing on the incoming cables is probably a bit long, but they may move so I've kept a bit of excess. Likewise the neutral and earths are looped as shown to maintain some excess.

The question I have is, is there anything particularly wrong with that routing?

I wasn't sure if it was best for the cables coming from the top to drop straight down and the ones from the bottom to go straight up, or if they should be routed along the bottom and up the sides, e.g. the single one there at the moment, would the earth be better going all the way to the left along the bottom and then up the left hand side, and the live and neutral the same but to the right?

Oh, last thing - this is the bigger picture:

I've added an isolator, looking at it now I think the meter tails should probably be shortened a bit, or at least clipped out the way.

Any advice guys, or anything else that stands out that needs resolving?

Thanks...

westward10 · Feb 1, 2023

How did you isolate the power to fit that isolator.
Can you show a clearer picture of the RCDs.

mainline · Feb 1, 2023

Andy Hames said:
Hi

First post and I'm a DIY-er so apologies if this is the wrong forum to start with.

I have a project at the moment that involves replacing a consumer unit. I've arranged for a proper inspection and certification down the line but in the mean time I have made a start on getting the circuits wired in where I can.

This is where I'm up to so far:
View attachment 105829

and this shows better how the wiring is routed:
View attachment 105830

I know some of the sheathing on the incoming cables is probably a bit long, but they may move so I've kept a bit of excess. Likewise the neutral and earths are looped as shown to maintain some excess.

The question I have is, is there anything particularly wrong with that routing?

I wasn't sure if it was best for the cables coming from the top to drop straight down and the ones from the bottom to go straight up, or if they should be routed along the bottom and up the sides, e.g. the single one there at the moment, would the earth be better going all the way to the left along the bottom and then up the left hand side, and the live and neutral the same but to the right?

Oh, last thing - this is the bigger picture:
View attachment 105831

I've added an isolator, looking at it now I think the meter tails should probably be shortened a bit, or at least clipped out the way.

Any advice guys, or anything else that stands out that needs resolving?

Thanks...

Leaving the single insulated cables that long isn't really achieving anything, personally I would shorten them and not bunch them behind the din rail.

The tails could do with being clipped up.

Why not a rcbo CU ?
Did you work live on installing the isolator ?

What is the size of your main fuse ?

Edit : Westwood Posted above as I was typing

JBW175 · Feb 1, 2023

First of all, welcome to the forum.

However…

No SPD, they look to be 63A type AC RCD’s, looks to have single 2.5mm cables going into 32A MCB’s

surely this is a wind up?

I can’t see a sparky signing it off and you getting an LABC compliance certificate.

Andy Hames · Feb 1, 2023

The isolation was by removing the main fuse, which I am aware should really have been performed by the DNO.

Is this what you wanted, or each of the banks?

The circuit plan is:

Andy Hames · Feb 1, 2023

mainline said:
Leaving the single insulated cables that long isn't really achieving anything, personally I would shorten them and not bunch them behind the din rail.

The tails could do with being clipped up.

Why not a rcbo CU ?
Did you work live on installing the isolator ?

What is the size of your main fuse ?

Edit : Westwood Posted above as I was typing

The choice of not using RCBOs came down to cost. The person paying the bill didn't have the budget.

The isolator was fitted with the main fuse removed, which from memory is 60A I think. The CU main switch is 100A rated, so is the new isolator.

mainline · Feb 1, 2023

If your main fuse is above 63 amps then the rcds are under rated.

westward10 · Feb 1, 2023

You have removed the service head fuse and are actually undertaking these works for someone else with no electrical competence.

timhoward · Feb 1, 2023

My most immediate concern....(of several)
Does this:

lead to this:

as your diagram seems to imply?

westward10 · Feb 1, 2023

Have you actually rewired this property.

Andy Hames · Feb 1, 2023

JBW175 said:
First of all, welcome to the forum.

However…

No SPD, they look to be 63A type AC RCD’s, looks to have single 2.5mm cables going into 32A MCB’s

surely this is a wind up?

I can’t see a sparky signing it off and you getting an LABC compliance certificate.

They're type A RCDs.
The single cable is one side of what will be a ring when completed.

timhoward said:
My most immediate concern....(of several)
Does this:
View attachment 105842

lead to this:
View attachment 105843

as your diagram seems to imply?

It does, that cable is one end of the kitchen socket ring. The other end of the ring that's also connected to that MCB comes in from the top of the CU.

davesparks · Feb 1, 2023

Andy Hames said:
The single cable is one side of what will be a ring when completed.

But it appears from the pictures that it is currently live?

If this is the case you need to stop and get a professional to sort this out before you cause some real damage that can't be undone.

timhoward · Feb 1, 2023

Andy Hames said:
It does, that cable is one end of the kitchen socket ring. The other end of the ring that's also connected to that MCB comes in from the top of the CU.

It's highly dangerous to have a coil of live cable on the floor with bare ends. Final circuits shouldn't be connected up until they are complete and tested.

Also, the other B32 MCB on the left shouldn't have a single 2.5 sq mm cable either as it isn't rated to carry 32 amps. (as mentioned higher up)

suffolkspark · Feb 1, 2023

Wheres your spd?
How much of a gap is there around the cables that enter the top of the cu through that gromit?
Where is the support for the tails (and other cables)?
Wheres your label on the MET?
Why is there a live coil of cable on the floor?
Whos doing notification to labc?
Why is there a 32A mcb serving a 2.5mm radial for 1st floor sockets?
Wheres your test results obtained prior to energising?

westward10 · Feb 1, 2023

I expect the 2.5 radial is still looping around the house live until it returns to the CU to complete the ring.

MJPD29 · Feb 1, 2023

Although it appears neat, there are a lot of mistakes would need rectified to meet regulation.

mainline · Feb 1, 2023

Is the 32 amp 2.5mm radial feeding a socket or sockets ?

Andy Hames · Feb 1, 2023

timhoward said:
It's highly dangerous to have a coil of live cable on the floor with bare ends. Final circuits shouldn't be connected up until they are complete and tested.

Also, the other B32 MCB on the left shouldn't have a single 2.5 sq mm cable either as it isn't rated to carry 32 amps. (as mentioned higher up)

No, that's not the same cable. There are 2 cables coming up through the floor. The coiled cable on the floor is the start of a separate ring and is not connected up or in any way live.

Taken on board the point about the 32A MCB, I was already intending to replace it with the spare 16A.

westward10 · Feb 1, 2023

Are you rewiring this property.

mainline · Feb 1, 2023

The first thing to do is to switch off those mcbs one at a time, then turn off the CU main switch followed by the isolator.
Then check the main fuse rating if above 63 amp, disconnect the entire CU and take it back to screw fix.

davesparks · Feb 1, 2023

mainline said:
The first thing to do is to switch off those mcbs one at a time, then turn off the CU main switch followed by the isolator.
Then check the main fuse rating if above 63 amp, disconnect the entire CU and take it back to screw fix.

I'd say the only thing to do is get an electrician in.

timhoward · Feb 1, 2023

@Andy Hames the board itself isn't bad at all in terms of neatness, but that isn't the be all and end all - there are a few things that you couldn't hope to know unless you've spent time studying the wiring regs.
There's a general principle that things are tested before they are energised, for good reasons.
I'd try and get a sparks on board to test what is there, and advise you on steps to finish this in a compliant way. There are people out there that don't mind DIY'ers doing the first fix.
Sorry I jumped to the wrong conclusion regarding that coil of wire. I was concerned for your safety.

mainline · Feb 1, 2023

davesparks said:
I'd say the only thing to do is get an electrician in.

Get the money back first to repay the client

Andy Hames · Feb 1, 2023

MJPD29 said:
Although it appears neat, there are a lot of mistakes would need rectified to meet regulation.

I don't doubt that, I do have a qualified electrician coming to do an inspection

westward10 said:
I expect the 2.5 radial is still looping around the house live until it returns to the CU to complete the ring.

mainline said:
Is the 32 amp 2.5mm radial feeding a socket or sockets ?

It currently feeds one socket, it won't be extended until the other side is completed.

mainline · Feb 1, 2023

Andy Hames said:
It currently feeds one socket, it won't be extended until the other side is completed.

It's fine on a 32 if only feeding one socket

westward10 · Feb 1, 2023

So are you rewiring this property.

mainline · Feb 1, 2023

@davesparks you don't agree Dave ? why not

Andy Hames · Feb 1, 2023

timhoward said:
@Andy Hames the board itself isn't bad at all in terms of neatness, but that isn't the be all and end all - there are a few things that you couldn't hope to know unless you've spent time studying the wiring regs.
There's a general principle that things are tested before they are energised, for good reasons.
I'd try and get a sparks on board to test what is there, and advise you on steps to finish this in a compliant way. There are people out there that don't mind DIY'ers doing the first fix.
Sorry I jumped to the wrong conclusion regarding that coil of wire. I was concerned for your safety.

No, no problem at all.

I do have a qualified electrician coming to check and advise and eventually do the EICR and certification, etc.

I'm fully aware there's a whole lot I don't know, but I have tried to learn and I've done some testing as best I can, for example the connected ring and the cooker radial I continuity and resistance tested each conductor as well as making sure there was no continuity between them before ever connecting them (as well as testing earth continuity between the cooker chassis and main earth).

I fully expected a fairly robust response but I'd rather ask than just carry on without doing so.

westward10 · Feb 1, 2023

So are you being paid to rewire this property.

DPG · Feb 1, 2023

Andy Hames said:
No, no problem at all.

I do have a qualified electrician coming to check and advise and eventually do the EICR and certification, etc.

I'm fully aware there's a whole lot I don't know, but I have tried to learn and I've done some testing as best I can, for example the connected ring and the cooker radial I continuity and resistance tested each conductor as well as making sure there was no continuity between them before ever connecting them (as well as testing earth continuity between the cooker chassis and main earth).

I fully expected a fairly robust response but I'd rather ask than just carry on without doing so.

It's not an EICR that needs completing.

You really didn't ought to be doing this work, especially if it is for someone else.

You need a calibrated MFT and the ability to use it and understand the results that it gives. You also need an understanding of the wiring regs and how to apply them

I'm all for competent DIY stuff, but this is beyond that.