Run Electric Supply to new build garage from 16 amp new build house CU

DIY Sparky · Nov 14, 2018

I am planning to run a power to the garage from a 16 amps RDC from house CU in a new build. I want a power a twin socket, an internal light, and a floodlight. There is a power feed to a junction box on the outside of the house from a CU. My plan is to install a power supply as per the attached sketch. I will call an electrician to connect and test the system. Planning not to have CU in the garage as i will not need any more supply and want to keep the cost down. Any advice will be useful and how much an electrician would charge to connect and test?

[ElectriciansForums.net] Run Electric Supply to new build garage from 16 amp new build house CU

The apprentice · Nov 17, 2018

I agree with the swa being earthed if you ran the cable from your house protected by a b32 and got a small metal 2 way consumer unit with a b6 and b16 b6 for the lighting and b16 for the socket it’s saves you spur of the socket with a fused spur for the lighting (just an apprentice)

Toneyz · Nov 17, 2018

Before the OP starts fitting a B 32A MCB maybe we need to know what size cable the housebuilder has put out for the future supply.

Deleted member 26818 · Nov 17, 2018

From what I understand, there is already in place a connection point and duct work for a cable to be run to the shed/garage.
It appears SWA is not required.
Not sure if notification is required, as this appears to be just extending an existing circuit?

Deleted member 9648 · Nov 17, 2018

spinlondon said:
From what I understand, there is already in place a connection point and duct work for a cable to be run to the shed/garage.
It appears SWA is not required.
Not sure if notification is required, as this appears to be just extending an existing circuit?

Even if it does not require notification it comes under part P and as such it is a legal requirement that the work complies with bs7671, which will include a requirement for certification,

Deleted member 26818 · Nov 17, 2018

wirepuller said:
Even if it does not require notification it comes under part P and as such it is a legal requirement that the work complies with bs7671, which will include a requirement for certification,

No, it’s not a legal requirement that the work complies with BS7671.
Compliance with BS7671 is just one method of complying with Part P.

DIY Sparky · Nov 18, 2018

DPG said:
I would also use metal clad sockets and pvc trunking and bushes.

Thanks, DPG, I am going to use metal clade twin sockets (only one) and two 5 amp fused metal clade switches to power an internal light and floodlight, this is only if approved by an electrician, which I am still finding one.

DPG · Nov 19, 2018

DIY Sparky said:
Thanks, DPG, I am going to use metal clade twin sockets (only one) and two 5 amp fused metal clade switches to power an internal light and floodlight, this is only if approved by an electrician, which I am still finding one.

Metal clad are always a good idea in a garage. I would personally fit at least 2 double sockets. One on each wall ideally. Think of if you have a battery charger plugged in, radio maybe. Then lawnmower. You get the idea. Easier to do it now than upgrade later.

DIY Sparky · Nov 19, 2018

The apprentice said:
I agree with the swa being earthed if you ran the cable from your house protected by a b32 and got a small metal 2 way consumer unit with a b6 and b16 b6 for the lighting and b16 for the socket it’s saves you spur of the socket with a fused spur for the lighting (just an apprentice)

Thanks for the response. House CU has already got a separate supply for the garage with 16 amps fuse. this supply is terminated in a junction box outside the house with conduit pipe buried underground to the garage wall.

DIY Sparky · Nov 19, 2018

DPG said:
Metal clad are always a good idea in a garage. I would personally fit at least 2 double sockets. One on each wall ideally. Think of if you have a battery charger plugged in, radio maybe. Then lawnmower. You get the idea. Easier to do it now than upgrade later.

thanks, my son only wants a minimum supply to the garage for internal light and outside flood light, he is not a DIYer at all.

DIY Sparky · Nov 27, 2018

DIY Sparky said:
thanks, my son only wants a minimum supply to the garage for internal light and outside flood light, he is not a DIYer at all.

People have stopped to advice, but see attached photo of the house CU, outside junction box and the black conduit pipe buried in the ground from the house to the garage wall.

Dave OCD · Nov 28, 2018

That looks a bit like a rushed bodge by the on site sparks tbh,the red plugs partially in the box tell me enough really,but the MCB needs to be turned off immediately and left off until the cable in the box is properly and safely terminated.

Toneyz · Nov 28, 2018

Dave OCD said:
That looks a bit like a rushed bodge by the on site sparks tbh,the red plugs partially in the box tell me enough really,but the MCB needs to be turned off immediately and left off until the cable in the box is properly and safely terminated.

Thats house bashing price work for you.

Toneyz · Nov 28, 2018

anthonybragg said:
Thats house bashing price work for you.

Sorry but I would still instal SWA (inc earth nut) to D.B.

Deleted member 26818 · Nov 28, 2018

Love the brick dust left in the box.

DIY Sparky · Nov 29, 2018

Dave OCD said:
That looks a bit like a rushed bodge by the on site sparks tbh,the red plugs partially in the box tell me enough really,but the MCB needs to be turned off immediately and left off until the cable in the box is properly and safely terminated.

Thanks, Dave, I was also very surprised to see the loose connection and CU on. I will speak to the site manager and switch off the garage supply from the CU.