Replace Consumer Unit - Professional Advice Required

[oxoboys]

Hello!

I want to have my consumer unit replaced and have already bought a new 10 way Fusebox CU with surge protection, 6 mini RCBOs, 4 blank modules and an intumescent strip in readiness for an electrician to install. However, I'm looking for advice from professional electricians only please on this forum BEFORE I instruct an electrician to do the work. This is because I've had several electricians tell me conflicting stories as well as quote vastly different prices for what seems to me like 2 to 3 hours work, maximum.

Please see attached photos: The feed from the meter box outside the property consists of a 3-core (1 spare core) MIMS cable which comes through the breeze block wall into the property where it is terminated on Henley blocks inside a black steel junction box (I've left the lids off for the purposes of the photos). From there it splits with 2 sets of tails: 1 goes to the old main consumer unit above it and the other goes to the white "garage consumer unit" to the left of it, which is now redundant and can be removed.

What I would like to know is this: Does the MIMS cable have to go to such a junction box before going onto the new consumer unit or can it be terminated directly inside the new CU? I'm trying to tidy up an unsightly mess in my entrance hallway and would like to have as few items of electrical hardware on show as possible.
If the MIMS cable must first terminate in a junction box, then I propose to have the current one moved a few centimetres to accommodate the new taller CU or better still have it replaced with a smaller one if that's possible.

Your thoughts please, professional electricians?

 

[blup]

I would be more concerned that my electrician knew how to - and did - professionally terminate the MICC whether in the CU or a jb. Likewise with the installation of the CU itself.

Not a professional electrician, just kick starting the debate.

Blup

 

[sparkwright]

If the MICC cable in the house is long enough to reach the new consumer unit, then it can go directly to the consumer unit.

It seems it hasn't got a proper gland on it: so it will either have one fitted by the electrician if he's good enough, or more likely it will just be poked through the bottom of the cu.

If he does the second option, it looks like he will have to consider earthing the MICC at the inside end as well as it already being done at the meter position, because it appears the copper sheath solely provides the earth.

Another option may be to forget about the MICC, and use tails or SWA - whichever proves to be more suitable...

You really need a switch fuse unit at the meter position as well, as no doubt the MICC is longer than 3m.

 

[oxoboys]

@sparkwright Thanks, that's useful to know. So there's no IEE regs that prevent that MICC cable from going straight into the consumer unit? If so, great!

The purist in me says the cable really should go through a gland, but that would look unsightly in my hallway, so I'd prefer the MICC cable to enter the CU through one of the two large rectangular knockouts in the back.

The MICC probably is longer than 3m due to all the slack you can see in the first picture, but it could be shortened and come in below 3m in total.

 

[old duffer]

I always assumed that the building regulations had to be followed and applied so how can the matter be subjective?
The home owner is the one nicked if the installer makes a mess so buyer beware

PS did you know you are 3 times more likely to die from drowning in your bath than you are by electrocution in the home

pps people still believe the electricity comes down a line from the power station and that it can flow backwards and forwards LOL

 

[flameport]

Reusing that MIMS cable will require that it's shortened to remove that large loop below the meter cabinet, and that it's properly secured to the wall. Possible if it's metric, but not if it's imperial. There is also the question of what size conductors it contains.
It can and should be glanded directly into the consumer unit, the other end will need an enclosure where it connects to the meter, rather than the mess that's there now with the inappropriate BS951 clamp.

As suggested already, replacing that cable with SWA is a more likely option.
Plenty of electricians can't deal with MIMS cable because they don't have the tools required, or that they haven't dealt with it before, or even if they have it was decades ago.
If the consumer unit position is directly behind the meter cabinet, using individual tails may be an option, which would be better for having the cable enter the rear of the consumer unit as they won't require a gland attached to the cable.

The junction box with the RDL connectors in it won't be needed in any case.

vastly different prices for what seems to me like 2 to 3 hours work, maximum.

The physical installation of the new consumer unit may take that long, but before any of that, all of the existing circuits must be inspected, tested, and any required repairs done. That makes it easily a full days work, possibly longer depending on the condition of those circuits.
Pretty much guaranteed with an installation of that age that the equipotential bonding to water, gas and whatever else exists will need to be upgraded.

a new 10 way Fusebox CU

Not a product I would have selected, however it is likely to be suitable provided the RCBOs are Type A, and not AC.
Note that by you purchasing it there will be no warranty, so if anything goes wrong with it, you will have to pay for someone to replace components as necessary.

 

[oxoboys]

If the consumer unit position is directly behind the meter cabinet, using individual tails may be an option, which would be better for having the cable enter the rear of the consumer unit as they won't require a gland attached to the cable.

The junction box with the RDL connectors in it won't be needed in any case.

@flameport the consumer unit is on the other side of the wall just visible on the left of the first picture, i.e. opposite the meter cabinet. Could individual tails still be used for such a run? (Approx 2.5 metres) If so, it would definitely make things easier and tidier.

The junction box with the RDL connectors in it won't be needed in any case.

Great, the less boxes visible on my wall the better.

Not a product I would have selected, however it is likely to be suitable provided the RCBOs are Type A, and not AC.
Note that by you purchasing it there will be no warranty, so if anything goes wrong with it, you will have to pay for someone to replace components as necessary.

Every electrician has their preference. I've seen plenty of good reviews and they're good value for money. More importantly, the RCBOs are "type A B" see https://www.consumerunitworld.co.uk/fusebox-6amp-mini-rcbo-type-a-b-curve-rtamb06-4023-p.asp
Purchasing the hardware myself was a risk I was willing to take.

 

[flameport]

Could individual tails still be used for such a run?

Yes, and far easier than faffing with that old MIMS cable or installing SWA.

 

[Adam_151]

as quote vastly different prices for what seems to me like 2 to 3 hours work, maximum.

You could *easily* spend that long re-dressing and re-terminating the ends of an MICC cable like that, maybe @RF Lighting could get it done a bit faster, but most of us would have to take our time over it.

It does sound that tails are the more sensible option in your case, but its nice to be told that sorting out a buggered about with 10mm MICC and fitting a new board on the end will only take a couple of hours. That and the fact that the board has already been purchased, I should imagine the reason for the differing prices is that some have a bad feeling about the job, so high ball it, so they either loose it, or if they get it, they can cover for things not going to plan and the job just being a a general pain.

Jobs involving adjusting existing MICCs generally have to be priced with either extra margin, or a rider to deal with it going a bit pear shaped because it can.

 

[Adam_151]

"type A B"

That would be (RCD) type A, B Curve (overcurrent protetcion). The website has dropped a comma

There is no type "A B" as that would be a silly way to phrase it, would cause confusion if you wanted it in C curve! (And you might be in for a shock looking at prices for an type AC B )

 

[JohnW2]

There is no type "A B" as that would be a silly way to phrase it, would cause confusion if you wanted it in C curve!

It would - but probably no more silly (and confusion-generating) than the fact that, after using "Type" to refer to the time/current curve of an MCB or RCBO, the word has suddenly come to have a totally different meaning in relation to RCDs and RCBOs!

Kind Regards, John

 

[blup]

The home owner is the one nicked if the installer makes a mess so buyer beware

But the electrician is surely morally legally and professionally accountable if he installs equipment and cabling in accordance with baby steps dictated by the home owner who in turn is relying on advice from a forum.

Blup

 

[old duffer]

But the electrician is surely morally legally and professionally accountable if he installs equipment and cabling in accordance with baby steps dictated by the home owner who in turn is relying on advice from a forum.

Blup

self certifiers are always right LOL...It's what they pay protection money for.
HSE has no jurisdiction in domestic dwellings and BC is meaningless after 12 months....
You can do what you like, there are no consequences

 

[mattylad]

Oxoboys, as above, you would be best putting (your electrician putting) in a fused switch in the meter box for the new tails.

Consumerunitworld only appear to do one type.

Hager VC02SW is an Enclosed Switch Disconnector suitable for Meter Box Applications.

Hager VC02SW is an Enclosed Switch Disconnector suitable for Meter Box Applications where an isolating switch between the electricity meter and consumer unit is required.

www.consumerunitworld.co.uk

 

[oxoboys]

Oxoboys, as above, you would be best putting (your electrician putting) in a fused switch in the meter box for the new tails.

Consumerunitworld only appear to do one type.

Hager VC02SW is an Enclosed Switch Disconnector suitable for Meter Box Applications.

Hager VC02SW is an Enclosed Switch Disconnector suitable for Meter Box Applications where an isolating switch between the electricity meter and consumer unit is required.

www.consumerunitworld.co.uk

Thanks mattylad, but I've just checked with my energy supplier (Bulb.co.uk) and they will come and fit an isolator switch for £120 or better still, only £60 if I agree to have my meters (gas & electric) swapped for smart meters at the same time.

I have so far resisted changing to smart meters but this seems like a good deal. Once the new isolator switch is in, it will be much simpler to connect the new consumer unit using ordinary tails.