What cable size to run to the garage.

[RaceDiagnostics]

When I lay new slabs round the front of the house I plan to take the opportunity to lay in a new armoured cable to the garage.

Although I have no plans to buy an EV at any time, it makes sense to ensure the cable is capable of supplying both a 7kw EV charger as well as the rest of the garage, i.e. a lathe, lift, compressor etc but seldom if ever at the same time.

Would a 6mm cable be compliant with diversity or do I need to go for 10mm? Are there any special regs around EV chargers that would have an effect on this. I also see that there are cables including a twisted pair for Comms.

 

[brightspark]

id go with 10.0mm with it having or possibly a 7k charging unit personally giving roughly 16 kw

 

[Barking Mat]

Since I started renovating my house, I had 16mm coming in, three phase, so to a new consumer unit I ran 16mm.

From the house to future workshop I equally ran 16mm, 20 - 25 meters, from the workshop to barn I've 10mm cabling to go in but need to dig a ditch for leccy, compressed air and maybe water for a tap.

Barn and workshop will be wired with 6mm to 32 amp outlets.

I'd go as big as your incoming cables, but brightsparks probably better to listen to than me.

 

[aesmith]

I also see that there are cables including a twisted pair for Comms.

Having just had to excavate all over again, in your shoes I'd lay a separate duct alongside the armoured power cable for any sort of data or control cables.

 

[addjunkie]

When I lay new slabs round the front of the house I plan to take the opportunity to lay in a new armoured cable to the garage.

Although I have no plans to buy an EV at any time, it makes sense to ensure the cable is capable of supplying both a 7kw EV charger as well as the rest of the garage, i.e. a lathe, lift, compressor etc but seldom if ever at the same time.

Would a 6mm cable be compliant with diversity or do I need to go for 10mm? Are there any special regs around EV chargers that would have an effect on this. I also see that there are cables including a twisted pair for Comms.

You want to buy the swa especially for car chargers with the inbuilt data cable for the CT clamp meter thing. Dont know why but I have it in my head the chargers needs to be on its own line, also the DNO come and inspect the job before giving the nod to install the charge point.

 

[jimbo84]

Depends on how long the run is, you could end up needing a 25mm depending on the length. Impossible to say without that info.

Best thing to do is as @aesmith suggested and stick a couple of ducts in, it’s future proofed then and no need to fork out for the cable until you need to.

 

[RaceDiagnostics]

The garage is about 15 from the house CU.

 

[jimbo84]

The garage is about 15 from the house CU.

Allowing 7kw for a car charger and another 5kw for the garage, heating in winter? (possibly too much but nothing worse than not having enough) assuming that the car charger is coming off the garage, so 12kw total on that cable to the garage you’d be looking at a 16mm.

Edit A 10mm would give you 10kw.

 

[brightspark]

Allowing 7kw for a car charger and another 5kw for the garage, heating in winter? (possibly too much but nothing worse than not having enough) assuming that the car charger is coming off the garage, so 12kw total on that cable to the garage you’d be looking at a 16mm.

Edit A 10mm would give you 10kw.

yep about rite at 15 m underground id alowed for less not underground

 

[RaceDiagnostics]

9m of the run would be under the floor clipped to joists.

 

[Agrismith]

Having just had to excavate all over again, in your shoes I'd lay a separate duct alongside the armoured power cable for any sort of data or control cables.

Definitely just go with ducting. It's really cheap and you never know what you might run in the future. Will save money if you don't ever install charger but also if you need other supplies.
Whole host of other things that we get asked to trench for now from CCTV to various data cables right though to larger cables to handle power walls and solar panels. Also putting heating pumps in funny places ( don't think remote heat pumps are recommended but we get asked to install the ducts)

 

[Pigeon_Droppings2]

Mine to the garage is 10mm...and same to the drive (pre planned for an EV charger about 12 years ago!)....10mm has been enough for what I need.

I doubt I'll ever need more than a 13a or 16a plug for the EV but good to have the cable in place.

 

[RaceDiagnostics]

Right, for the time being ill stick in a duct for future use and use this for power to the garage CU as it will cost less than £50.

 

[Barking Mat]

All of my cabling came from FB Marketplace, less than half price compared to market values.

 

[Bobupndown]

Since I started renovating my house, I had 16mm coming in, three phase, so to a new consumer unit I ran 16mm.

From the house to future workshop I equally ran 16mm, 20 - 25 meters, from the workshop to barn I've 10mm cabling to go in but need to dig a ditch for leccy, compressed air and maybe water for a tap.

Barn and workshop will be wired with 6mm to 32 amp outlets.

I'd go as big as your incoming cables, but brightsparks probably better to listen to than me.

You're running underground compressed air pipes?

 

[julianf]

All of my cabling came from FB Marketplace, less than half price compared to market values.

Exactly how i did it. I have 16mm installed.

 

[Morrisman]

Last time I bought some SWA cable the price for the correct coloured stuff was crazy, but a sparky told me I can use any coloured wire as long as I sleeve the ends of each cable in the correct colour heat shrink. That halved the cost of what I’d been looking at.

 

[MetalMonkey]

Right, for the time being ill stick in a duct for future use and use this for power to the garage CU as it will cost less than £50.

Just something to note.

Depending on the construction of the garage and the earthing arrangement, two core may not be suitable.
Chances are you are on a PME supply, and when exporting the earth you need to consider bonding - the armour of the cable may not be sufficent.

If you want to be sure and cover yourself, install a three core.

 

[Ed.]

When we built our house last year (and moved in this year) on our 1/2 acre block, I got hold of a roll of 25mm square 4C+E 3 phase cable. It is connected to the street pit and then to a box next to the shed about 18m away which contains the main meter, from there it goes to the house at the back of the block, however that 25mm cable was reduced to 16mm via a short pigtail at the first box due to the energy companies meter. So if you can afford it, pay once and more for it and you don't have to worry about it later on. Having the thicker cable means that there is less voltage drop under heavy current and we are limited to 40A per cable.

Having said all that, I will be connecting the shed next to the main box via 10mm cable and to all the 3 phase outlets. So anything I want to connect to them will have more than ample power. I do not intend to ever purchase an EV but will have the infrastructure to do if I change my mind. I would recommend getting at least 16mm and preferably 3 phs that way you have covered all bases. For the record I would hate to use all 40A on each phase as that would cost nearly $9.50/hour to run.

We are about to purchase a new car but there is no way I would consider an EV, in OZ it is not practicable for the long driving distances involved and we do not want to wait hours for it charge up in the middle of the trip assuming we can even find a charging point.

 

[8ob]

Right, for the time being ill stick in a duct for future use and use this for power to the garage CU as it will cost less than £50.

View attachment 447965

I would pay the extra and go for three core.

Bob