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

[DIY Sparky]

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?

 

[Octopus]

No idea .... I never test and inspect other peoples work.

Best you find a spark willing to do this before you do anything AND this falls under part p of the building regs too

 

[DIY Sparky]

Thanks, Murdoch, i fully understand where you are coming from re the building regs that is why I want the electrician to connect all wires and test. I want to do all the labour work to reduce cost. Just wanted to know if my thinking on the scetch is right. I will not do anything without checked and tested by an electrician as it is my son's new house.

 

[Octopus]

Thanks, Murdoch, i fully understand where you are coming from re the building regs that is why I want the electrician to connect all wires and test. I want to do all the labour work to reduce cost. Just wanted to know if my thinking on the scetch is right. I will not do anything without checked and tested by an electrician as it is my son's new house.

As I previously stated, find a spark to work with and ask them ....

 

[Toneyz]

You need an electrician that belongs to a third party scheme. How much they charge I don't know maybe another member could answer that. I think that they would check the design and inspect at intervals.

 

[Toneyz]

If it was me I would install 3 core SWA cable to the garage earthing the SWA with an earthnut (to earth the SWA) and install a small consumer unit (2 way). I assume that as noted it is a new house and the supply to the outside box complies with the 17th edition of BS7671. If a photo of existing C.U. and outside box was posted I could comment further.

 

[MJPD29]

I like the drawing you have done your research well

 

[Michael Davis-McCoy]

Hi Anthony,
Why would you use a 3 core swa instead of a 2 core swa. The 2 core's are the right colours and for single phase. You would have to sleeve the 3 core.

 

[BruvDunk]

Always better to future proof any additions. i.e. workshop.
So a small garage CU would be the way i'd recommend.

What type of cable would depend on route etc, but SWA is always a favourite..
A decent Electrician will explain all this when he prices it up.

 

[DPG]

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

 

[Toneyz]

Hi Anthony,
Why would you use a 3 core swa instead of a 2 core swa. The 2 core's are the right colours and for single phase. You would have to sleeve the 3 core.

You can get three core SWA in brown, blue and green/yellow if not sleave or tape it. As for the 3rd core as CPC always have done, reliable and don't have to worry too much about corrosion.

 

[Deleted member 105166]

Dig the trench and run the pipe/ducting with a draw string. The electrician will appreciate you doing this aspect. Then let him specify and pull the cable through, as otherwise he cannot inspect it.

 

[DIY Sparky]

As I previously stated, find a spark to work with and ask them ....

Thanks, Murdoch, I am working on this at the moment.

 

[DIY Sparky]

Dig the trench and run the pipe/ducting with a draw string. The electrician will appreciate you doing this aspect. Then let him specify and pull the cable through, as otherwise he cannot inspect it.

Thanks, the outside connection box from house 16 amp CU, underground pipe and ducting has already been installed as per the sketch during the new build. The distance between the house and the garage wall is 4 meters.

 

[DIY Sparky]

Always better to future proof any additions. i.e. workshop.
So a small garage CU would be the way i'd recommend.

What type of cable would depend on route etc, but SWA is always a favourite..
A decent Electrician will explain all this when he prices it up.

Thanks, Paul, my son is not a DIYer at all, he will only power a lawn mover plus just need a power to an internal light and floodlight. I might occasionally use the 13 amp socket for hand tools.

 

[The apprentice]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

Thats house bashing price work for you.

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

 

[Deleted member 26818]

Love the brick dust left in the box.

 

[DIY Sparky]

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.

 

[DIY Sparky]

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

Definitely fitting the SWA that will be connected/tested by an electrician.

 

[DIY Sparky]

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

Definitely fitting the SWA that will be connected/tested by an electrician.

Love the brick dust left in the box.

Yeah, it is not only this dust left but lots of other bodge jobs I have found that you can not see on the new build when buying. Site manager does not want to know.

 

[Dave OCD]

That seems to be so common now sadly, some of us do still have standards though but I fear we all get tarred with the same brush sometimes.

 

[DIY Sparky]

I spoke to the site manager and now they have asked my son to deal with HQ, even though they are building new houses very nearby. Further, most of the electricians in my town are busy until the new year and want to do the whole job. So leaving the project until early next year, unless some electrician is willing to help to connect and test after I have done the groundwork.
Many thanks to all for sound advice and have a fabulous Christmas.

 

[Simon-0116]

Is it a metal shed, and is there water in it. Makes a difference.

 

[DIY Sparky]

It is a new detached garage with no electrics

 

[DIY Sparky]

That seems to be so common now sadly, some of us do still have standards though but I fear we all get tarred with the same brush sometimes.

You are right. no matter how careful we are, there is always someone who will take advantage.

 

[telectrix]

i suggest you do the groundworks, bury a duct at a sensible depth ( 15" - 18" is considered enough, less if under slabs/paving ) with drawstring in. bedded in sand, sand on tot, warning tape then fill in. no sharp bends. then sparks can design the cable size and type and complete the job.

 

[DIY Sparky]

The new build already has a black pipe ducting buried underground for the house to the garage walls.