As with most things electrical - it depends! Read on to find out if your existing electrical system is capable - or if it will need upgrading.
As a general rule - installing the charger either inside or outside your garage is a good idea - inside is great if that is where you usually park your car - but if you normally keep it on the drive in front of your garage - then it's probably wiser to have the charger installed on the outside of the building unless you have specific security concerns - as it's less likely that the charging cable will get damaged by the door when you close it.
So from a regulations point of view - this is fine - the question you are probably really asking is about if your existing garage power is up to the job.
A normal home charger will use 32 amps (7.4 kilowatts) of electric whilst in use.
To put this into perspective - your house hold socket circuits (ring main) is rated at 32 amps - and with all of your appliances on - this 32 amp limit is rarely if ever reached.
In other words - EV chargers demand a lot of electricity and put a high demand on your home.
To work out if you can fit a charger in your garage - lets look at some key components of your existing home electrics to see if its possible.
Firstly you need to find out which circuit breaker in your home fuseboard / consumer unit is feeding the power to your garage and see how big it is.
Usually you would expect this to be 20, 32 or 40A - you also need to ensure that this circuit is ONLY feeding your garage DB.
Next you will want to look in the garage at the consumer unit. In many cases this may just have a 6A lighting circuit and a 16A socket circuit. Does the unit have any 'spare ways'? (See photo - from right to left it has a Type A 40A RCD, a B6 MCB, a B16 MCB and a blank - or spare way) See the post it note at the bottom of the photo for helping identify if you have a Type AC or Type A RCD.
Also note that the RCD has a yellow test button on it - MCB's (or miniature circuit breakers)
do not have a test button. Some houses will have a combination of RCD and MCB - these are called RCBO's and are generally the same width as an MCB but with a test button - and the little rectangular sign showing the type of inbuilt RCD within the device.
It is also crucial that the size of cabling into the garage is correct for the fuse or MCB size that is feeding the garage from the main house. Any reputable electrician responsible for the original installation of the garage electrical system should have made sure that this cable is correctly sized but it will be useful to check this. If the cable is a round black cable (SWA) then you may be able to read the size off the side of the cable - it may say 3 x 2.5 or 3 x 4 for example.
OK - so lets see what this information means in reality.
If you are lucky enough to have found a 3 x 10mm (or bigger) cable being fed from a 50A MCB or RCBO from the main house - only have a handful of sockets with minimum demand on a 16 or 20A MCB and a 6A lighting circuit, wuth a Type A RCD within the garage consumer unit - plus a spare way - then it should be a straigtforward installation running a new circuit from the spare way into your new charging point.
This however is unlikely to be the case. Much more common is for the garage to be on a 20A MCB from the house with a 2.5mm cable. Here we have a couple of options. You could fit a charger - perhaps with a new sub-consumer unit with the correct RCD fitted - but you would have to limit the amount of power that the charger can use - this would require a system called 'dynamic load balancing'. In this scenario - a device called a CT (or current transformer) is fitted around the live part of the cable coming into the garage consumer unit - this is connected to the charger and the system is set up to only use up to the maximum power for the garage circuit (so 20A in this case) - if another appliance demands energy - a freezer coming on for example - the power going to your car decreases to ensure that the total current used by the garage circuit stays below the 20A. NOTE - that in this case - the maximum charge rate for your car will be 4.6 kW
Here - the selection of the charger becomes important because it must be able to support the dynamic load balancing.
The second option is to have a new cable installed from the house which is dedicated to the charging socket - usually we would recommend that this is run directly from the metering point to keep it completely separate from your house electrics. It will undoubtedly be a more costly job - but ultimately you will be able to take advantage of all 32A and 7.4 kW of power to charge you car completely in a few hours (or overnight on a low electricity tariff such as is offered by Octopus Energy - see https://octopus.energy/compare-ev-tariffs/ )
Another consideration is that you may have to have your main electricity fuse upgraded - especially if you have only a 60A fuse - see our other blog about 'can any electrician install an EV charger for more details on this : https://www.ev-electrical.com/post/can-any-electrician-install-an-ev-charger?utm_source=linkedin&utm_medium=blog.post-promoter&utm_campaign=68fface3-d633-4080-bbdc-1aa483d65938
Having all of the above information collected is a great help when getting yourself a quotation to have an EV charger installed - we would however highly recommend that you contact a dedicated EV charging company to carry out any installation work - most (like ourselves) will offer a free no obligation survey to ensure that any quotation is accurate and that all of your expectations for the charger are understood and met.
More than anything - EV charging companies such as ours are experts in the field and can offer a great deal of advice on the whole 'driving EV' experience - plus we are extremely approachable!
I hope that you have found this article of use and we look forward to helping you on your electric journey.
