Overheating EV install

littlespark · Dec 12, 2022

Had a call from a parent of one of my daughters friends…

” Do you do electric car charge points”

“Well, no. Not installation, but I can diagnose faults…. Tell you what’s needed. “

“I’ve already phoned the supplier. Not interested. 3 weeks out of the warranty period. “

So here’s the charge point.

[ElectriciansForums.net] Overheating EV install

And here is where I think the problem lies.

Ok. Severe overheating on supply neutral cable.

Easy enough to fit a new box, rerterminate the ends… but I’ve got a couple questions of the EV experts.

1. Heat caused by loose connection or over current? What load should this charge point be taking? Is it going to happen again if I replace this box and remake the joints.

2. What is the small core twisted cable with the red tip device be for?

pc1966 · Jan 7, 2023

If they put in a 1.2m / 4' rod then 125 ohms is not very surprising, it would be what to expect from around 175 ohm.m soil resistivity which is about mid-range for most soil types. However, it would seem a touch high for a winter in Scotland with ground pretty damp sort of situation.

It does meet the 200 ohms for the regs and of course is well below the theoretical 1.6k needed for a 30mA RCD and 50V max sustained voltage.

EDIT: Some example values:

Soil Resistivity Values for Different Types of Soil

Soil Resistivity reference, Earthing, Earth Electrode

www.electricalengineeringtoolbox.com

Gavin John Hyde · Jan 7, 2023

Its a chargemaster/ bp pulse unit... has to be my least favourite ev charger company, shocking customer service and damn awful charger units.
Its a personal victory for me when i remove one of those knowing its off to the skip and nobody else will have to endure it.

They were clever in getting in to garages and places early to offer 'free' installs or cheap installs but never innovated. the quality of installation though has in my view been shocking... sure some may be done well. but all the ones i have seen have been lacking.

The red button on newer units replaced the old jumpers to switch between 16/32A.
If damaged you may be able to replace it, but bp pulse/chargemaster are a closed shop and dont ordinarily supply spares outside the company. they will gladly charge a substantial call out fee and supply parts which when compared to a new unit such as a bg sync ev or evec unit i would go with a new unit.

littlespark · Jan 7, 2023

That’s good to know that the 125 is within normal boundary’s.
I was worried that the installer maybe couldn’t get it down and just left it.

Yes wet Scottish soil, but rod and charge point right next to a road, so could be a bit hardcore-y

The button works… click in, click out… so I just cut out the damaged piece of wire and connected it. Just a bit shorter.
If the button had been fried, I would have just left connector with a link between.

How do you get into that charge point anyway? The key just turns the socket on and off.
There are a load of screws on the back of the front plate, but would need a dumpy Phillips to get them out.

Gavin John Hyde · Jan 8, 2023

littlespark said:
That’s good to know that the 125 is within normal boundary’s.
I was worried that the installer maybe couldn’t get it down and just left it.

Yes wet Scottish soil, but rod and charge point right next to a road, so could be a bit hardcore-y

The button works… click in, click out… so I just cut out the damaged piece of wire and connected it. Just a bit shorter.
If the button had been fried, I would have just left connector with a link between.

How do you get into that charge point anyway? The key just turns the socket on and off.
There are a load of screws on the back of the front plate, but would need a dumpy Phillips to get them out.

they have a weird backplate where you need to remove various screws - used to be hex/security screws on some models to release it from the bracket, being located in the middle on base.