Adding a second CU

[Easty]

Hi
I have searched this forum and have a rough understanding of the answer to my Question, but I just want to be 100% clear as to how this is done. I am not a qualified electrican and do not intend to do the work myself.
This is my situation:
My Garage in being converted into a music studio which will have seven double sockets on one circuit to power a computer, amps, mixing desk and other electrical music gear.
I was also going to have one double socket on a separate circuit to power a 3kw electric heater and lastly two light fittings (3x50w spots) on a lighting circuit.
My question is Can a second mini CU be connected to my exsisting CU to supply two socket circuits and a lighting circuit?
My exsisting CU is in the garage and has space around it for a second CU, but has no spare MCB's (see Photo below)


An electrican I know has suggested buying a 4way consumer unit and he will connect the three cables into MCB's in the new unit.
I was also wondering what cable was used to connect the two CU's and where would he connect to in the exsisiting CU.
Sorry to go on any advice would be appreciated.
Many Thanks
Easty

 

[andy]

split the tails is the best way to do it, but you either have to work live puttin a cable into a henly (NOT recommended for DIYers and people with little knowledge) or ask the DNO (some charge) to install an isolator, so you can then put cables into henly to split the in safety. your sparky will know the best way and may be able to add an isolator without gettin the DNO to come disconnect/reconnect

are you aware that youll need to comply with building regs (unless your sparky is able to self-cert his work)

 

[Har_vey]

Hey Easty. Can you back up a bit and take another shot so that we can see the meter and the cut out?

I assume that the black item to the right of the meter is the cut out, but just on the off chance, wondered if there might be a henly block already installed?

 

[Easty]

Har_vey

Here is a bigger picture.


Is there an alternative to splitting the tails?

Thanks
Easty

 

[comms]

Why not just change the complete board, for one with a smaller mainswitch instead of the hulking great ELCB, then use 32amp rcbo's for the socket circuits ?

 

[Qedelec]

I was under the impression that elcb's were now considered undesirable and should be replace asap.

 

[Spark123]

I was under the impression that elcb's were now considered undesirable and should be replace asap.

Do you mean voltage operated? The one in the picture is current operated type which are still OK. It is not very desirable to have the whole installation protected by a single 30mA device though...

 

[securespark]

Easty,

I am compiling a technical piece for work regarding testing rcds.

Could I have your permission to use your photo as an example of an electro-mechanical RCD?

 

[Har_vey]

Easty. I'd change the existing unit to a split board. That way your new circuits can be wired direct to the new cu and it should give you the option of having spare ways for any future circuits. Not a bad idea given what you have planned for your garage.

Your electrician should'nt have any problem with testing your exisiting installation and upgrading as required.

 

[Easty]

securespark

Of course you can use the photo thanks for asking.

Is there anyway a 4way CU can be connected without the expense of changing the complete board??

Thanks
Easty

 

[Pensdown]

securespark

Of course you can use the photo thanks for asking.

Is there anyway a 4way CU can be connected without the expense of changing the complete board??

Thanks
Easty

One Option. Install a second 4 way CU. Transfer the one of the 6amp circuits into the new CU. Feed the new CU via a 45amp breaker in the old CU via 10mm tails now you have 3 new ways in you new CU

 

[Har_vey]

I would say that changing the board for a split wouldn't be a great deal different to adding a new board. Any additional work to bring it to current regulations has to be done either way.

I suppose the exisiting circuits might cause some problems but You have an NICEIC sticker on the front of your exisiting cu, so you would hope that the installation is up to a certain standard anyway, would'nt you?

Why not get your spark to give you two prices?

 

[Easty]

Thanks for your comments
Easty

 

[securespark]

Easty. Thanks! I've been looking everywhere for a photie of this type of RCD and everytime I see one at a customer's house, I don't have my digi camera with me!

 

[securespark]

Securespark Calling Easty......

Can you e-mail me with your name so I can credit you with supplying the picture I want to use?