Overheating EV install

[littlespark]

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]

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]

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]

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]

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]

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]

I thought it looked like a simple pushbutton

 

[DPG]

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]

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]

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

 

[littlespark]

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]

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]

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]

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]

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.