EV Charging Point - Detached Garage

Grippo

Hi, I’m looking in to getting an electric car charging point installed at my house. The installer has suggested coming from the main fuse box in the house, with a cable boxed in by trunking around doorways to get to an external wall. But I would prefer the charging point to be on the outside of my detached garage.
The garage has its own fuse box at the back. So I presumed (with little electrical knowledge) that that would be an easier and tidier installation solution. But I’m struggling to get the installer to confirm if that’s the case.
Can anyone give me an idea if the garage installation is likely to work or not? Thank you.

Keep_pedalling

It is highly unlikely that the current power supply to the garage can support a 32A charger so you are going to need a dedicated supply.

silvercar

We had similar, the power needs to be linked back to the main consumer board.

sheenas

A number of reasons not to use the garage. Firstly the
cable is unlikely to be up to it and for sure you have an old garage consumer unit. Have a new small consumer unit with anti surge and a suitable RCD near the meter, will ensures the cable and charger are protected. Normally the cable is protected and no trunking is needed, anyway the sparky seems to know what he is doing.

WIAWSNB

Hi Grippo.

What type of vehicle - full EV, or a Phev? 

With the latter, there should be the option to charge at a lower rate of around 2.4kW, in which case your existing garage supply will almost certainly be fine - that's a standard 13A socket's worth. 

If, however, it's a full EV, or you wish to charge a Phev at a faster rate, then you will require a dedicated supply from the main house CU, just as to your hob/cooker and electric shower. 

What route does the existing garage supply take from the house? Can't the new cable follow this so you can get what you want? 

Grippo

Thanks everyone for your replies. I’m glad I asked as it sounds like it’s not possible to use the existing garage electrics.

WIAWSNB said:

Hi Grippo.

What type of vehicle - full EV, or a Phev? 

It’s a full EV.

WIAWSNB said:

What route does the existing garage supply take from the house? Can't the new cable follow this so you can get what you want? 

The cable seems to go down to the floor from the house consumer unit. Although the house has a concrete floor as opposed to a suspended floor. So it must go below ground level to the garage?

Heedtheadvice

If your installer cannot tell you if feeding from the garage is possible or not then perhaps a better installer?

Having said that it is better not to cut corners for EV charging IMHO. A full ev home charger normally is capable of 7kW power control ( and you may need that to keep charging time minimised to in the order of under 10 hours) a smart charger and smart meter and EV electricity tariff to make best use of cheaper overnight charging. Lots of info regarding that on the Green and Ethical forum.

bjorn_toby_wilde

Grippo said:

Thanks everyone for your replies. I’m glad I asked as it sounds like it’s not possible to use the existing garage electrics.

WIAWSNB said:

Hi Grippo.

What type of vehicle - full EV, or a Phev? 

It’s a full EV.

WIAWSNB said:

What route does the existing garage supply take from the house? Can't the new cable follow this so you can get what you want? 

The cable seems to go down to the floor from the house consumer unit. Although the house has a concrete floor as opposed to a suspended floor. So it must go below ground level to the garage?

Mine is wired direct from the meter and the main consumer unit.  When it was fitted we also had to have the main electricity board fuse uprated before they could go ahead.

My experience with a PHEV was 10-12 hours for a full charge via the 13a plug type charger.  That’s not very good for a PHEV, let alone an EV which is why I had the charging point installed.

The cable used is pretty hefty (18-19 mm thick) so any boxing would have to be quite deep to take this plus the cable clips.

I’m sure you won’t be able to follow the same route for cable to the garage as that will have been sunk in the ground when the house was built.

WIAWSNB

Grippo said:

Thanks everyone for your replies. I’m glad I asked as it sounds like it’s not possible to use the existing garage electrics.

WIAWSNB said:

Hi Grippo.

What type of vehicle - full EV, or a Phev? 

It’s a full EV.

WIAWSNB said:

What route does the existing garage supply take from the house? Can't the new cable follow this so you can get what you want? 

The cable seems to go down to the floor from the house consumer unit. Although the house has a concrete floor as opposed to a suspended floor. So it must go below ground level to the garage?

Ok, in that case wiring it from the existing garage unit is a non-starter, as will be your car.

You will need to wire a dedicated supply from your house consumer unit to the desired charger location. Your call where this is to be, but bear in mind how awkward the cable will be to run. 

Always worth getting a couple of sparkies out to quote, not only for the price, but for their thoughts on how to run it. 

chrisw

Where's the electric meter? My installation connects straight to the meter box on the outside wall and doesn't touch the consumer unit.