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.

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?

snowhead · Dec 12, 2022

I think I'd get the customer to send the second picture to the installer / supplier and add text,
"Just for reference in case other customers complain, this is what 3 weeks out of warranty looks like on one of your installs"

SparkyChick · Dec 12, 2022

I would say, based on the apparent lack of thermal damage on the line conductors (apart from where they've been toasted by the neutrals) it's down to a bad joint at the chock block they used on the neutral.

Edit:- I'd have a look at other points on the cable... if there's no signs of thermal damage anywhere else it's down to the termination not an overcurrent situation.

littlespark · Dec 12, 2022

As it was -8 where i was, i wasn't going into too much examination of the entire installation.... but now ive got the feeling back in my fingers...

You can see the supply cable on the bottom left isn't an SWA. It's 3 core Tuf-Sheath or whatever... Ill check the route back into the house when i replace the box.

Earth rod somewhere under the snow. The earth wire goes down the flexi conduit on the right. Not connected to supply earth.

Short piece of flexi between top of box and charge point. Will have to replace the tails unless there's some spare in the charge point itself.

The box lid hardly fitted back on, as it was starting to melt too.

Lucien Nunes · Dec 12, 2022

Definitely faulty connection, as the line is OK despite carrying the same current. Plus, if a terminal had been sound and of low resistance but the cable was overloaded, it would have overheated more where it is bunched and less at the terminal because that provides a heatsink.

brianmoooore · Dec 12, 2022

No comments on the device with the red tip yet.
Looks like a small panel mount thermal current trip, like a MCB, but without the instant trip part.
No idea what it's got to do with a charge point though.

Lucien Nunes · Dec 12, 2022

I thought it looked like a simple pushbutton

DPG · Dec 12, 2022

90% certain that's a push button. What's it do? You've got to try pressing it - it's the law when you find a button!

littlespark · Dec 12, 2022

i wonder if it fixes to the lid somehow, but has obviously melted off its support. Was nothing on the inside of the lid though.

brianmoooore · Dec 12, 2022

Push button or trip; what's it doing there and what's it connected to?

littlespark · Dec 12, 2022

I’ve been having a Google looking for details of this charge point, and on a dedicated EV forum, someone mentioned a “push button in the junction box to switch between 16A and 32A”

So that might be what the red button does, and if so, I’m going to have to replace it.

Still looking for a decent installation manual showing connections, and possibly a set up procedure.

SparkyChick · Dec 12, 2022

littlespark said:
I’ve been having a Google looking for details of this charge point, and on a dedicated EV forum, someone mentioned a “push button in the junction box to switch between 16A and 32A”

So that might be what the red button does, and if so, I’m going to have to replace it.

Still looking for a decent installation manual showing connections, and possibly a set up procedure.

It doesn't look like it's IP rated, so was it actually mounted in the junction box in such a way so as to be accessible, and operable by the user?

If not, I would establish whether it's a simple push to make switch... if it is and it was not installed in a way to allow the user to operate it, I wouldn't worry about it.

pc1966 · Dec 13, 2022

DPG said:
90% certain that's a push button. What's it do? You've got to try pressing it - it's the law when you find a button!

as Sir Terry Pratchett put it:

“Some humans would do anything to see if it was possible to do it. If you put a large switch in some cave somewhere, with a sign on it saying 'End-of-the-World Switch. PLEASE DO NOT TOUCH', the paint wouldn't even have time to dry.”

Dranok · Dec 14, 2022

While I appreciate Uncle Terry as much as the next geek, my mind first went to the earlier quote:
ARTHUR: I wonder what happens if I press this button...
FORD: No, don't!
ARTHUR: Oh!
FORD: What happend?
ARTHUR: A little light lit up saying Please Do Not Press This Button Again.

littlespark · Jan 5, 2023

Been back at this job this morning and replaced the box, cut back all the melted cable and reterminated.

Going through the testing afterward and the earth loop was 125 ohms.
This is not from PME from house, but a rod. Found the top of rod just below charger, less than a metre away. No sign of corrosion.
Seems high to me, but as I’m not an EV installer, and don’t come across this on a daily basis, I thought I’d better ask you lot.

Left turned off just now. Customer is still away for new year, and got the electric car away so I couldn’t test it plugged in.

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.