Speak EV - Electric Car Forums banner

1 - 18 of 18 Posts

·
Registered
Joined
·
416 Posts
Discussion Starter #1
I have recently experienced some problems with my (reputable, professionally installed, OLEV compliant) 7kW charge point. It's fed from a 40A stand-alone RCD, and after a year or so of use it tripped the breaker a couple of times. It reset ok, but then tripped again and, when reset, appeared to power up as usual and reported that it was charging, but at zero power.

Still under warranty so got the original company out to have a look...the picture shows the output connections to the car. Looks like an insecure live connection from the original installation. Unfortunately the guy who came back wasn't the original installer, and they were quick to say that they'd used a subcontractor originally (not that that matters, of course). Remarkably little damage but yet another reminder of how this stuff can go wrong. I'll be paying close attention to temperatures in future, although there was no visible, olfactory or other way of sensing this failure as far as I could tell!

135216
 

·
Super Moderator
Joined
·
7,505 Posts
Thank you for sharing, and I would say to anyone else reading, if your breaker is tripping SOMETHING IS WRONG! Just because you can't identify it doesn't mean there isn't a problem.....!
 

·
Registered
Joined
·
17,400 Posts
Thanks for sharing your snuff pictures.

I'm about to decommission my EV charger after 4 years, so I'm going to look carefully for signs of burning.
 

·
Registered
Joined
·
4,302 Posts
Can someone explain to me why the pins in the Type 1 and 2 cables that go into the car have to be professionally crimped with a hydraulic crimping tool to give an adequate low resistance joint for continuous 32 amps, yet we keep seeing wiring to the input side of 32 amp EVSE's that look like they're using cheap regular small screw terminal chocolate blocks which you could buy from B&Q ?

Surely they're not up to the task of providing 32 amps for hours at a time day after day, year after year, and the fault is not that the screw was loose and started to overheat, but that the wrong type of screw connector was used in the first place ? (Or that there shouldn't even be an unnecessary terminal connector there - as discussed in another thread where an EVSE had a short stub cable joined to the main incoming cable with a terminal block - why ?)
 

·
Registered
Joined
·
2,205 Posts
Many industrial connectors (eg the commando) use screws just fine. Even for the much larger 63A versions of the commando plug.
 

·
Registered
Joined
·
2,749 Posts
If those are used they need to be really really really tight. My brother is a sparky and he really tightens them. If possible put the copper right through the connector from both sides. Then clamp both pieces of copper together in two spots with the two screws. If there is any loosness at all it will heat up over time and melt - no doubt about it.

PS Chocolate block I am talking about. Used in loads of fittings - comes as bought
 

·
Registered
Joined
·
3,853 Posts
Can someone explain to me why the pins in the Type 1 and 2 cables that go into the car have to be professionally crimped with a hydraulic crimping tool to give an adequate low resistance joint for continuous 32 amps, yet we keep seeing wiring to the input side of 32 amp EVSE's that look like they're using cheap regular small screw terminal chocolate blocks which you could buy from B&Q ?

Surely they're not up to the task of providing 32 amps for hours at a time day after day, year after year, and the fault is not that the screw was loose and started to overheat, but that the wrong type of screw connector was used in the first place ? (Or that there shouldn't even be an unnecessary terminal connector there - as discussed in another thread where an EVSE had a short stub cable joined to the main incoming cable with a terminal block - why ?)
The terminations inside the EV Connector are a system designed as fit for purpose. Those chocolate block connectors are random field installed things.
Any trade experienced & responsible person would use a Pratley or Phoenix etc connector. Or in a pinch, at least a bootlace crimped ferrule inside the chocolate block.
 

·
Registered
Joined
·
3,326 Posts
Or in a pinch, at least a bootlace crimped ferrule inside the chocolate block.
Yeah, I looked at image this morning and the first thing I though of was, have they used crimped ferrules or just stripped back the single insolation and made off the individual lines into a choc block, surely not !.
But when zooming in on the image, it does look like they have used crimped ferrules by the looks of it - Phew !.
Impossible to tell if the "live" line had a ferrule connector, given the state of it.
But you would suspect it would have been fitted with one given that all the other lines appear to have them fitted ?.
One can only assume that the "live" line connection was not torqued up correctly at one, or both ends of the choc block at the time of the original install then ?.
 

·
Registered
40 Leaf
Joined
·
144 Posts
Can someone explain to me why the pins in the Type 1 and 2 cables that go into the car have to be professionally crimped with a hydraulic crimping tool to give an adequate low resistance joint for continuous 32 amps, yet we keep seeing wiring to the input side of 32 amp EVSE's that look like they're using cheap regular small screw terminal chocolate blocks which you could buy from B&Q ?

Surely they're not up to the task of providing 32 amps for hours at a time day after day, year after year, and the fault is not that the screw was loose and started to overheat, but that the wrong type of screw connector was used in the first place ? (Or that there shouldn't even be an unnecessary terminal connector there - as discussed in another thread where an EVSE had a short stub cable joined to the main incoming cable with a terminal block - why ?)
IMO any connector used in such circumstances should be over rated by at least 30%

Commando sockets have 2 screws per terminal and you strip back 20-25mm of insulation which allows twice the contact area with these terminals.

this is why you don’t see thesekind of issues occurring with these type of connectors.

if you insist on using terminal blocks I would recommend ceramic ones that are large enough to accommodate fully overlapping both cables inside and fully tightening the screws so that both screws clamp both cables.

Job done!
 

·
Registered
Renault Zoe ZE50 GT-Line Rapid Charge
Joined
·
1,979 Posts
if you insist on using terminal blocks I would recommend ceramic ones that are large enough to accommodate fully overlapping both cables inside and fully tightening the screws so that both screws clamp both cables.

Job done!
Any block designed for high loads should list torque settings on the spec sheet.
 

·
Registered
Joined
·
2,749 Posts
  • Like
Reactions: Carty

·
Registered
40 Leaf
Joined
·
144 Posts
Much rather do it myself if that's what a "professional" installed.
You’ve only got to look at all of the issues with the smart meter roll out and loose terminals to realise you can’t trust anyone!

I’m not suggesting that folks should go installing their own charge points for one moment, a good level of understanding and competence is required to even contemplate this.

it’s obvious that a good number of us on here have an electrical background (I was a fire alarm engineer for 10 years).

But it seems that even when a “professional” has installed your point a it needs some vigilance and a smoke alarm nearby the connection to the dis board isn’t a bad idea!

Maybe the 18th edition should require one??

Especially as it ages or you upgrade to a vehicle that is charging at a higher current than your previous car!
 
1 - 18 of 18 Posts
Top