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UMC plug and socket getting warm

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Got my UMC plugged in at a friend's house for a top-up. Not used it before but noticed that that the plug and socket are noticeably warm to the touch.

Does this happen to you? My thoughts are leaning towards a fault in the socket. I don't think it should be getting warm at all.

Reasonably modern installation, approximately 20 years old would be my guess.
 
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Thanks very much. I've had the chance to try it on a different socket on a different ring and the same thing happens, so I'm not that concerned.

I think they're just cheap and nasty sockets, though if time permits tomorrow might whip one off the wall and check the terminals are tight.

Won't leave it on charge overnight here though.
 
Thanks very much. I've had the chance to try it on a different socket on a different ring and the same thing happens, so I'm not that concerned.

I think they're just cheap and nasty sockets, though if time permits tomorrow might whip one off the wall and check the terminals are tight.

Won't leave it on charge overnight here though.
I've been charging my M3 for the last year using the UMC. Melted through two Poundland Extension Cords. Nothing dramatic, just the fuse blowing in both eventually. Spent a bit more on a Masterplug one since, and while it's still warm to the touch, it hasn't melted yet !
 
If you're charging somewhere for the first time, it's worth stopping the charge after 30 mins or so, unplugging the plug and feeling the prongs. If they're anything more than warm, don't keep using the socket.

The poor connection is less likely to be between the prongs of the plug and the socket, unless you can see marks or discolouration. It's more likely to be within the socket itself, or between the wiring and the screw terminals on the back of the socket. This means that if the prongs are warm, the other parts of the socket are likely to be hotter.
 
Standard 13A house plugs are not intended to carry a continuous 2kw to 3kw for 12 hours. For this sort of load I'd use a 16A commando socket and plug, much heavier duty. They are not expensive, even if fitted by an electrician and Tesla supply a 16A Commando plug connector for the UMC.



Less than £40.00, plus fitting.
 
The commando socket below appears not to be compliant with UK regs in most installations as it is not interlocked (or shuttered) - that is, it doesn’t have an on/off switch that prevents the plug being removed unless power is off so live terminals can be ‘prodded’.

If anyone is considering going 'off piste', this post (supersedes earlier posts in the thread) by a a 'former' member who is qualified on the subject is worth a read if looking at various options of installing a compliant installation. Obviously, anyone not wanting to meet regulations is there choice, but I really don't think non compliant solutions should be promoted as a 'normal solution. Basic charge point costs

Standard 13A house plugs are not intended to carry a continuous 2kw to 3kw for 12 hours. For this sort of load I'd use a 16A commando socket and plug, much heavier duty. They are not expensive, even if fitted by an electrician and Tesla supply a 16A Commando plug connector for the UMC.



Less than £40.00, plus fitting.
 
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The commando socket below appears not to be compliant with UK regs in most installations as it is not interlocked (or shuttered) - that is, it doesn’t have an on/off switch that prevents the plug being removed unless power is off so live terminals can be ‘prodded’.

If anyone is considering going 'off piste', this post (supersedes earlier posts in the thread) by a a 'former' member who is qualified on the subject is worth a read if looking at various options of installing a compliant installation. Obviously, anyone not wanting to meet regulations is there choice, but I really don't think non compliant solutions should be promoted as a 'normal solution. Basic charge point costs
I used this complaint socket which doubles up for caravan charging/feed.
 
I can’t get the OLEV grant, so when I bought my car more than two years ago I looked for a cheaper alternative to a charge point and decided on a 32A interlocked commando socket. I did all the wiring myself, including wiring into a separate mini consumer unit, and just had a local sparky complete the wiring into the main consumer unit and do all the tests to make sure it was installed properly. It’s been 100% reliable for the last two years and cost very little.

It is not compliant with current regs so I would never recommend anyone else do the same. What has always puzzled me though is that my commando socket setup is essentially the same as using a UMC. Sure, the current for the commando is higher but the voltage is the same and the principle is the same. I’d suggest that using a UMC on old/dodgy wiring is probably more dangerous than my commando socket.
 
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I'm pretty sure on modern housing, 2KW is fine to run through a regular socket, just watch the heat coming off it. It will get warm, there's always resistance in the wire.
The sockets are rated for 240V x 13A, i.e. just over 3KW.
Also the Tesla mobile charger has some fancy circuitry (maybe just a temperature monitor) that will detect if the plug socket is going bad.

My parents have owned a Tesla since 2019 and charged exclusively off a 3pin the entire time.
 
I'm pretty sure on modern housing, 2KW is fine to run through a regular socket, just watch the heat coming off it. It will get warm, there's always resistance in the wire.
Very true. The problem is the significant amount of housing that has old or dodgy wiring without people realising it.
Also the Tesla mobile charger has some fancy circuitry (maybe just a temperature monitor) that will detect if the plug socket is going bad.
So does the commando charger. It looks very similar to the UMC but obviously has a thicker cable and a different connector. On mine I can adjust the charge current, which of course you could do in the car or via the app as well.
 
What has always puzzled me though is that my commando socket setup is essentially the same as using a UMC. Sure, the current for the commando is higher but the voltage is the same and the principle is the same. I’d suggest that using a UMC on old/dodgy wiring is probably more dangerous than my commando socket.
This has also puzzled me. I guess the reasoning is that a UMC is generally only used on an occasional basis as a backup. However, there are a significant number of people who use the UMC on a permanent basis. I used mine as the only method of home charging for over a year. If a commando socket isn’t considered safe then a UMC shouldn’t be either.