EV charging point for my car..... melting the 3 pin plugs!

Millie Master

Millie Master

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We own an utterly gorgeous BMW 225XE with which we are delighted. It is a 2017 model and had done next to no mileage when we purchased it back in January this year.

Everything about the car is perfect for us, however shortly after we first bought it I noticed that the correctly fused plug and circuit breakered unique power line, hadn't either fused or tripped the throw out switch, yet both the socket and the plug had quite literally melted and the positive post of the plug had partly melted and fused itself to the terminal in the plug!!
So I thought this might be down to the fact that the plug and socket were both of Chinese origin and I bought a specific power point from the UK company Rolec and installed it. Everything went perfectly until a couple of weeks ago when I noticed that the very same thing had happened again, melted socket, melted plug!!

The circuit has a 10 amp throw out breaker switch in the consumer unit, it also has another similarly powered 10 amp breaker in the Rolec hook up point and the 3 pin plug has a 10 amp fuse fitted to it, yet none of these had tripped or blown????

I am now thinking of getting rid of the 3 pin plug and fitting a EHU type socket complete with a 10 amp trip as well as a correct waterproof IP67 EHU type plug as these should have more than enough capability of carrying the loadings of a basic EV hook up cable.
Of course I could get the professionals in, but I can think of far better ways of spending my hard earned!!

Any thoughts would be greatly appreciated
 
You require a charging unit of about 50kw and a cable as thick as a donkeys dangler, the battery is trying to pull a high current which will melt what you have, they dont tell you this when buying.
The cable is acting as a resistor cutting the current, so will get hot and melt.
 
From your decription, I would be inclined to change the socket to a Blue "Commando" 16A Socket, getting the genuine MK one.
This will have the bonus of giving a EHU point for any passing Motorhome member in need of a hookup :D (or you could even use it for Millie if you want :) )
 
trevskoda said:
You require a charging unit of about 50kw and a cable as thick as a donkeys dangler, the battery is trying to pull a high current which will melt what you have, they dont tell you this when buying.
The cable is acting as a resistor cutting the current, so will get hot and melt.
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Thanks for that Trev..... however although I understand what you write, the cables both in and out of the current socket are remaining very cool/cold, it is only the positive post of the plug and the socket which are going tits up! After all the standard home charging cable and plug as supplied by BMW comes with a standard 3 pin plug and only a 10 amp fuse and the thickness of the cable has 2.5mm wires inside it.

So I am hoping what Wildebus is suggesting which is exactly along the lines I have been thinking is the way for this oh so tight ass to follow.
 
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Millie Master said:
Thanks for that Trv..... however although I understand what you write, the cables both in and out of the current socket are remaining very cool/cold, it is only the positive post of the plug and the socket which are going tits up!

So I am hoping what Wildebus is suggesting which is exactly along the lines I have been thinking is the way for this oh so tight ass to follow.
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I don't know how well you will recall the change in the design, but quite a while back the design of UK 3 pin plugs changed to add insulation on the Live and Neutral pins for safety and that resulted on a significant thinning of the pins.
I have not had the problem myself, but I remember at the time fears expressed that this would result on overheating of the plug on high-current applications. Maybe this is the problem you are getting?
 
I've just got a Mitsubishi outlander phev which comes with a 13amp plug and haven't had a problem.
I wonder if the cable isn't making a good contact in the plug, my suggestion is to either crimp the ends which are attached in the plug or run solder to make the conductors to hold together before connecting them in the plug.
Also buy a quality plug.
 
wildebus said:
I don't know how well you will recall the change in the design, but quite a while back the design of UK 3 pin plugs changed to add insulation on the Live and Neutral pins for safety and that resulted on a significant thinning of the pins.
I have not had the problem myself, but I remember at the time fears expressed that this would result on overheating of the plug on high-current applications. Maybe this is the problem you are getting?
Click to expand...
Yes that happens to some plugs, had it here a few times, its the spring blade in the female unit being weak thus poor contact.
Those home thin cables are not much good for charging, my mate got an uprated one which has never gave trouble, but he uses a proper home charging hub which is linked to solar roof panels as well as the grid.
 
Lee said:
I've just got a Mitsubishi outlander phev which comes with a 13amp plug and haven't had a problem.
I wonder if the cable isn't making a good contact in the plug, my suggestion is to either crimp the ends which are attached in the plug or run solder to make the conductors to hold together before connecting them in the plug.
Also buy a quality plug.
Click to expand...
So Lee, in your valued opinion, what are the very best available 3 pin plugs?

Great idea about running solder into the wire strands, I am onto the case!

Many thanks

Phil
 
I've had a look and I would try a heavy duty permaplug as they are recommended for powertools.
 
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St3v3 said:
Than the maximum 2.5mm2 cable? ;)
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No, just thinner than before :) I was just saying when they introduced that pin type, there was some outcry amongst electrical folk of it being a future problem. And as I said, I've never found it a problem personally.
 
As stated by others...go for a quality 16A plug and socket. The problem is the poor "resistive" connection at the 13A plug. The resistance causes localised heating. Your thoughts on changing out the original (oriental manufactured) plugs was heading in the correct direction especially if you are confident the cables stay cool.
 
Yesterday I removed all the wires in both the plug and socket and soldered them as suggested by Lee and when I next need to charge, I will be checking the temperature of the plug and socket. Bearing in mind I have now changed the in car setting to the medium setting, I am hoping they will both remain nothing more than warm..................... However if they are to my personal touch warm feelings, then toot sweet I will be changing the socket and plug to 16A types as manufactured by MK.

Interestingly enough, having seen me pratting around with my charge cable, a nearby BMW I owning resident has followed my lead and has discovered his cars 3 pin plug and socket are getting quite hot!!

Phil
 
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We have a Leaf and regularly charge at home using the supplied cable & 13amp plug without issue. If you have 10 amp fuse & breaker I assume it can’t be drawing more than that. 2.5mm cable is more than adequate. Overheating can be caused by loose connections somewhere usually in the plug or socket, coiled cable, or an excessive run leading to voltage drop. Or perhaps there is something wrong with the in-line gubbins.
 
Sorry to say that despite my mods and having the charger set to the medium charging rate, after only 30 mins. the plugs body was almost too hot to touch and the positive prong actually burnt my most beloveds finger when she touched it (silly ass that she was to do so :ROFLMAO:) .

So my order for the 16 amp socket and plug from MK has just been placed.
 
Millie Master said:
Sorry to say that despite my mods and having the charger set to the medium charging rate, after only 30 mins. the plugs body was almost too hot to touch and the positive prong actually burnt my most beloveds finger when she touched it (silly ass that she was to do so :ROFLMAO:) .

So my order for the 16 amp socket and plug from MK has just been placed.
Click to expand...
sounds like a much better option, and also better weather protection for an outside fitting.
 
Hi we use our 13A EV charger all the time with no problem. I used to be an electrician and would see this problem lots, its due to a poor quality socket which burns both the plug and socket, sometimes a loose fuse can cause it as well.
Change both the plug and socket at the same time and use MK or similar. Also check that there is no cable strain causing the pins to be pulled at an angle to loosen the socket connection.
If you do swop to a 16A IEE connector check the circuit rating it's probably 32A ring main so you will need the 16A socket fusing down to 16A
 
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