Is drawing 6amp for 10 hours safe

[Spare tyre]

Long story short, my wife has a little EV that does about 100 miles a week at most, the car is our local car, we have other cars for holidays / out of town stuff

The 3 pin (13amp) granny charger that came with the car is fixed to 10amp which is the max a U.K. granny should goto when using conventional plugs/sockets

I wasn’t happy using extension leads etc as it’s just faff / extra stuff to go wrong

I purchased a third party 10meter granny cable that has a selectable 6/8/10/12 amp setting

I’ve been charging the car on a Monday (the cars here and so am I) for a few months now at 6amp and everything has been fine - it works

I enquired with my trusted sparky about having a 32amp commando socket installed, he didn’t want to do that and suggested a dedicated setup at £1250. Whilst I have the money it’s a lot more than I want to spend

The cunning plan was have beefy wiring run for the commando socket and we can always replace the commando socket for a proper solution in the future keeping the wiring

Is my spark on some special commission and gets a nice earner from installing his stuff?

Anyway, the question is: am I being a silly sod from a safety perspective charging at 6amp on my ring main?

Many thanks

[James6112]

My wife’s phev had been charging @ 10amps.
A few days a week, overnight, over a year.
My self installed external socket.
No problems!

[b14]

My Mercedes-supplied granny charger has been charging our PHEV every day for the past year off a plug socket at 10amps using a normal extension lead. It doesn't even get warm, so you should be fine.

[dhutch]

Should be totally fine.

It's the same as a 1400w fan heater, while 12-13A is pushing it, 8/10A should be fine too.

[biggiles]

Been running a PHEV at 10 amps for six years, charging for hours each day. Unless it's a really dodgy socket or extension lead, it should be absolutely fine. Most extension leads will say something like "rated for 6A coiled or 10A uncoiled".

[guitarcarfanatic]

The problem with Granny chargers or commando sockets is they lack Pen Fault detection. So if you were going this route, I would strongly suggest you install a standalone PEN fault device if not fitting a proper EV charger. Without this, the bodywork of the car could become live if there was a fault with the local grid. Hence why the regs change and that new EV chargers have to have this built in.

Obviously not an issue if you have a TT earthing system (to ground rather than via the grid).

But 6amp draw on a 13amp socket is fine. I think they are normally OK up to 10amp for sustained loads. You can get EV specific 13amp sockets if your worried which have a tougher plastic and less susceptible to heat.

[Actual]

For some time we charged 2 PHEV with 10A chargers using separate 3 pin sockets which were on the same ring final circuit rated at 32A and it was fine.

We also ran the washing machine, dryer and dishwasher on another ring final circuit at the same time.

I was also using extension leads and I did remake one which was running hot at the plug.

When our consumer unit was upgraded I had 2 separate 16A radial circuits installed specifically for PHEV charging.

The electric smart meter in-house display is very useful for confirming the whole house load as various items are switched on and off.

[dhutch]

guitarcarfanatic said:

The problem with Granny chargers or commando sockets is they lack Pen Fault detection. So if you were going this route, I would strongly suggest you install a standalone PEN fault device if not fitting a proper EV charger. Without this, the bodywork of the car could become live if there was a fault with the local grid. Hence why the regs change and that new EV chargers have to have this built in.

Obviously not an issue if you have a TT earthing system (to ground rather than via the grid).

I meant to post this, but yeah, its definitely a thing if you have a PME supply.

You appear to be able to get a little consumer unit, prepopulate, for about £90.
Combine this with an 13a outdoor socket and crack on?

[andy43]

Granny charging at 10 amps via a metalclad MK socket in the garage since 2015.
There is an rcd but it’s not the posh EV special one.
There could be a theoretical argument that the approx 10% charging losses reported on granny chargers (iirc) would be reduced by fitting a proper 32 amp wall charger but it’s not bothered me that much to read up on it.
We are still uncooked and alive. So far…

[Evanivitch]

guitarcarfanatic said:

The problem with Granny chargers or commando sockets is they lack Pen Fault detection. .

Or all domestic EV chargers installed before 2018. The risk is tiny.

[silentbrown]

guitarcarfanatic said:

The problem with Granny chargers or commando sockets is they lack Pen Fault detection. So if you were going this route, I would strongly suggest you install a standalone PEN fault device if not fitting a proper EV charger. Without this, the bodywork of the car could become live if there was a fault with the local grid. Hence why the regs change and that new EV chargers have to have this built in.

Obviously not an issue if you have a TT earthing system (to ground rather than via the grid).

I'm curious why is this a particular issue with EVs/chargers - Isn't any metal-cased appliance going to have the same risks?

[TonyRPH]

silentbrown said:

I'm curious why is this a particular issue with EVs/chargers - Isn't any metal-cased appliance going to have the same risks?

The same risks exist with your machine machine, dishwasher, fridge etc., however the metal casings are all connected to ground whereas a car is not.

[Simpo Two]

I wish they could just call it '13A' or 'normal household supply' instead of 'granny charger'

[Actual]

Simpo Two said:

I wish they could just call it '13A' or 'normal household supply' instead of 'granny charger'

Ironic considering that plugging in at your gran's house is more likely (as applies to my family) to be an older type property with an inferior electrical installation and the internal wiring may not cope with a high load.

[Simpo Two]

Actual said:

Simpo Two said:

I wish they could just call it '13A' or 'normal household supply' instead of 'granny charger'

Ironic considering that plugging in at your gran's house is more likely (as applies to my family) to be an older type property with an inferior electrical installation and the internal wiring may not cope with a high load.

I suspect there are plenty of EV owners who use a 13A socket in the their own house without taking it round to a grandmother's house (if they have a grandmother). Equally EV owners can live in older properties while their grandmother lives in a new-build bungalow. So it's a stupid term.

[silentbrown]

TonyRPH said:

silentbrown said:

I'm curious why is this a particular issue with EVs/chargers - Isn't any metal-cased appliance going to have the same risks?

The same risks exist with your machine machine, dishwasher, fridge etc., however the metal casings are all connected to ground whereas a car is not.

Why doesn't the charger connect the bodywork to earth? Wouldn't that avoid the problem entirely?

[Spare tyre]

Simpo Two said:

Actual said:

Simpo Two said:

I wish they could just call it '13A' or 'normal household supply' instead of 'granny charger'

Ironic considering that plugging in at your gran's house is more likely (as applies to my family) to be an older type property with an inferior electrical installation and the internal wiring may not cope with a high load.

I suspect there are plenty of EV owners who use a 13A socket in the their own house without taking it round to a grandmother's house (if they have a grandmother). Equally EV owners can live in older properties while their grandmother lives in a new-build bungalow. So it's a stupid term.

I assumed it was a double meaning, granny is slow / use it at grannies house

[TonyRPH]

silentbrown said:

Why doesn't the charger connect the bodywork to earth? Wouldn't that avoid the problem entirely?

It likely would (and the body might well be connected to ground when charging) - however I don't know enough about EVs to answer that.

Hopefully someone else can answer this?

[Mr Pointy]

TonyRPH said:

silentbrown said:

Why doesn't the charger connect the bodywork to earth? Wouldn't that avoid the problem entirely?

It likely would (and the body might well be connected to ground when charging) - however I don't know enough about EVs to answer that.

Hopefully someone else can answer this?

There's a couple of videos that look into it:
https://www.youtube.com/watch?v=gZVx7GbAwlg
https://www.youtube.com/watch?v=JRHyqouJPzE

[silentbrown]

Mr Pointy said:

There's a couple of videos that look into it:
https://www.youtube.com/watch?v=gZVx7GbAwlg
https://www.youtube.com/watch?v=JRHyqouJPzE

Videos both explain the problem (TN-C-S broken PEM causes all earthed stuff to become live) but doesn't explain why it's a particular concern with EV chargers? Just as likely to get 230V on the kitchen taps, surely?