Adding new circuits to full CU? (Ed.)

[mox1]

If things go well on here the discussed project will be carried out by an approved electrician.......that's not me.
Plan is for garage to be converted into living space andcwill accommodate the following:
TV, 1.5kw panel heater, fridge, dowlights and 4x twin sockets.
First question?
No spare ways at main cu. Can the cu in my house accommodate an additional 40amp mcb if upstairs + downstairs lighting is double upd in 6 amp mcb (see attached)?

 

[ETAF]

what space is available around the CU

 

[mox1]

Not alot of space. What you thinking?

 

[ETAF]

you maybe able to add a separate unit , just depends on space , layout and where the meter is located.

 

[Taylortwocities]

Like many similar installations, your whole house has one RCD (main switch). This means that an earth fault on ANY circuit will cut power off to the whole house until the problem is resolved. This is not only bad practice, it also goes against more up to date regulations.

Your plan to combine the lighting circuits also goes against the requirements of 'separation of circuits'. Your CU also is made of plastic. This also doesn't meet today's requirements. Any new circuits must meet the up to date requirements. Adding a secondary unit really only kicks the can down the road, and that can is called "install a new CU that meets todays requirments"

You said

the discussed project will be carried out by an approved electrician

and that's your next step. The work will need notification, so make sure that he/she is registered with one of the LABC recognised schemes.
Look here https://electricalcompetentperson.co.uk/

 

[JohnD]

Your new CU could best have RCBOs, rather than a small number of RCDs. This will cost more, but is a better solution.

You old CU is fine quality, but about 25 years old, and has no room for expansion. It would be possible to retrofit RCBOs, but this would be expensive and no easier than a complete refit, which will be a better job, and you can allow room for future expansion. A large empty tin box costs little more than a medium-sized empty tin box.

By chance I have a very similar one, but mine is (IIRC) a 20-way, and already has RCBOs, so has a bit more life in it.

 

[ericmark]

There are many options, when my mother lost her leg, and the kitchen needed redoing, the whole house needed a rewire. Dad would not allow it, so had to find a workaround, what we did was have a 40 amp MCB in the existing consumer unit (CU) feed a small new CU in the kitchen using SWA cable, so that cable did not need RCD protection, and have RCBO's in the mini CU in kitchen.

Be it Ali-tube or SWA there are cables which do not need RCD protection. So someone has to look at what you have, and design a system to get around the problems, and he will sign the installation certificate where it says design, also someone needs to do the work, and they sign they have installed, and someone inspects and tests, and they sign for that.

However, most of the scheme providers don't use multi signature installation certificates, so one person has to do it all, however, they still have to do the design. We can't design it on a forum, it has to be done by someone on site.

The CU you show is no longer suitable, it will need changing, if for no other reason it would be hard to get any parts to fit it. The consumer unit is a type tested distribution unit, and to retain the type testing, you can only use parts which the manufacturer have included in the type testing.

At the end of 2021 Kempston Controls announced its acquisition of MEM (Midland Electrical Manufacturing). The deal includes Eaton’s Memshield I & II ranges of circuit protection devices and also the Cutler Hammer DC crane controls.

so it is unlikely you can get new parts for that box, that are permitted to be fitted. So not real option but to renew it.

However, likely it will be cheaper to renew it anyway, as obsolete stock can be very expensive to get, and also unlikely you can get type A RCD's or RCBO's for that box, so you need to find a scheme member electrician to design what is going to be used, I would go for a firm rather than one-man band, as last thing you want is for an electrician to be ill at a crural moment.

 

[Murdochcat]

If you had a spare way it would be perfectly acceptable to add it to the existing board

But

Bite the bullet, get the CU replaced before your builder starts and make sure you have 3 or 4 spare ways

 

[JohnD]

you can only use parts which the manufacturer have included in the type testing. so it is unlikely you can get new parts for that box, that are permitted to be fitted.

The Memera 2000 and 2000AD CUs also fit MCBs and RCBOs from the Memshield2 range. That's what I have, and you can still get them.. At the time I was working in an industry where they were widely used and highly thought of. The ranges were specially designed so you couldn't fit Memera parts into Memshield.

Rather expensive, unless you are just doing one or two circuits.

 

[sparkwright]

If you had a spare way it would be perfectly acceptable to add it to the existing board

But

Bite the bullet, get the CU replaced before your builder starts and make sure you have 3 or 4 spare ways

I would change it too, it's not worth messing around with it.

It's a poor set up anyway, having an RCCB as a main switch. If there is a fault, you lose everything.

Far better to get a new board with RCBOs.

 

[flameport]

If you had a spare way it would be perfectly acceptable to add it to the existing board

Only if you ignore 314.1 and 531.3.2

 

[mox1]

Thanks for the replies all. Il be upgrading the CU.