Car Charger using garage consumer unit.

Hi all, for future planning I just want to clear up this question;

I have a consumer unit in my garage fed from a 40A MCB via 6mm SWA cable ( no more than 7m total length) from the house consumer unit. Can I have a charger installed (7kw) connected to my garage consumer unit rather than to the house consumer unit?

thanks.

Perhaps.

Depends on what else is in the garage, whether the circuit from the house is RCD protected or not, whether it shares that RCD with other circuits, and whether the garage CU has an RCD for more than one circuit, or has a main switch with RCBOs, and if there are any spare ways in it.

Plus all the usual criteria such as total loading in the house, size and type of supply, main bonding present, surge protection present, etc.

Don’t see why not !

A tricky thing with EV chargers is they can draw a lot of current for much longer than most other comparably sized domestic loads, as a result the probability of them causing an overload of the incoming supply is much higher.

To mitigate this many EV chargers come with "grid limit" functionality where they will dial back the charging current to limit the total load presented by the installation. That functionality depends on being able to measure the incoming grid current. Some manufacturers do offer wireless soloutions for this, but there is always a risk with wireless soloutions that they will not work properly in a given environment.

Not all EV chargers are the same, some only require a type A RCD, some need a type B, some can't be used with a TN-C-S supply others can, some need a reference electrode in the ground, some need a full earth rod.

House supply can be between 60 and 100 amp, with lower size fuses having the charge point measure what house uses is important.

You have to use a registered installer to get the government grants, so down to the installer how he thinks it should be done.

AndyPRK said:

Don’t see why not !

Click to expand...

Well…there’s a long list. But let’s start with the supply method. If the incoming service is “looped” then it can’t happen without a DNO upgrade.
So that’s the first maybe why not , and we aren’t even at the service fuse yet…