I wish to lay in a cable between the consumer unit and a wall where a one room ground floor extension will be built. It wont be connected till required next year. The extension will require one ring for power sockets, one for lights and one for external electrics and I expect the electrician to install a small consumer unit. Do I use a 6mm or 10mm cable for the job? I have been told (by electricians) to use both sizes.
cable size for building extension?
- Thread starter mosscutter
- Start date
A ring will be 32amp, lights will be 6amp and the external requirements will be????
Why a sub board, why not direct cable back to the existing cu, or incorp the light and ring in to existing circuits.
Only you know the load requirements for the new area and that will dictate the cable size if you go sub board. Personally given the unknown and given that it would be a cable once I'd go as large as you can.
What sort of distances between boards are we talking, would drop be an issue?
Why a sub board, why not direct cable back to the existing cu, or incorp the light and ring in to existing circuits.
Only you know the load requirements for the new area and that will dictate the cable size if you go sub board. Personally given the unknown and given that it would be a cable once I'd go as large as you can.
What sort of distances between boards are we talking, would drop be an issue?
Unless the extension is an annexe incorporating loads such as immersion heaters, electric showers or cookers then a sub-CU is a bit of overkill.
The only other reason for a sub-board would be if extending existing circuits made them too big or overloaded them.
If the main CU is not too far then it might be more worthwhile running new circuits.
Above all, ask your electrician who will do the work as only he knows what he needs and he can carry out the work for you.
The only other reason for a sub-board would be if extending existing circuits made them too big or overloaded them.
If the main CU is not too far then it might be more worthwhile running new circuits.
Above all, ask your electrician who will do the work as only he knows what he needs and he can carry out the work for you.
Then have your electrician install it, or them, next year. With an extension you can't avoid a Building Regs submission so you'll have to use an electrician and you'll want him to sign documents to say that he did it all.
Thanks for your informative replies, much appreciated. My CU whilst being new seems to be full and whilst I have the ceilings open its easy to get a cable installed. Being only a "two down" house I guess extending the ground floor ring and lights will be ok. Whatever method is used I want any preparatory work done now to stop unnecessary mess later.
It's more desirable to have just one mains position.
If your cu is full a new cu may be put alongside it, or if it's out of date a larger could be fitted in it's place.
It's not as simple as running one large cable from the mains to the new extension, as other cables may still be needed between - such as interlinked mains smoke detector wiring (this may be a requirement) and lighting/switch wiring for hallway etc etc.
Your electrician may not wish to extend some existing circuits if they are badly done, or already serving a lot of points.
Get the electrician to put the cables he needs in now.
If your cu is full a new cu may be put alongside it, or if it's out of date a larger could be fitted in it's place.
It's not as simple as running one large cable from the mains to the new extension, as other cables may still be needed between - such as interlinked mains smoke detector wiring (this may be a requirement) and lighting/switch wiring for hallway etc etc.
Your electrician may not wish to extend some existing circuits if they are badly done, or already serving a lot of points.
Get the electrician to put the cables he needs in now.
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