UK domestic 3 pin extension lead

[.jg.]

If charging at a friend's house, using an extension lead that may not have a high current rating, there is always the option to reduce the rate of charge. Obviously, charging will take longer but if you are staying overnight and you only need to top up enough to get to a supercharger, even charging at 5A may be enough.

For those who decide to buy or construct an adaptor from IEC 60309 Commando to BS1363 13A plug, remember to reduce the charge rate, to avoid tripping breakers. I made a Commando to Schuko cable, for use on the continent but actually used superchargers or destination chargers during my trip to France, so I haven't used it yet.

 

[marcovb]

Hi,
I’m planning on charging from a 3pin plug when I visit family at Christmas. I can park next to the garage so can get the UMC charger out of the rain. Am I then ok to run a standard extension lead from the garage to the house?
I can reduce the level of charge too if that’s advised as can charge overnight and will only need a top up. Obviously assuming the house has decent electrics and won’t trip.
Thanks!

 

[MrBadger]

Am I then ok to run a standard extension lead from the garage to the house?

It depends on your definition of 'standard extension lead'. Not all are equal, not all are rated to run 10A continuous. Charging a car at high amps for extended periods of time is very different to running say a steam wall paper stripper for 20 minutes. I wouldn't go near anything that wasn't rated 13A and tbh, I wouldn't go anywhere near anything that wasn't H07RN-F cabled, which isn't your standard extension cable. Whatever you decide, make sure it is fully uncoiled. Dedicated extension cables from reputable sources are not expensive and if they use H07RN-F cable really do not take up much space.

 

[Neilman]

Hi,
I’m planning on charging from a 3pin plug when I visit family at Christmas. I can park next to the garage so can get the UMC charger out of the rain. Am I then ok to run a standard extension lead from the garage to the house?
I can reduce the level of charge too if that’s advised as can charge overnight and will only need a top up. Obviously assuming the house has decent electrics and won’t trip.
Thanks!

Assuming the house socket you are going to use is clean and new that should be a good start - if it's discoloured or clearly an old design it might not like a continuous 10Amp load. Check the temperature of the plug frequently to be sure it's OK otherwise you may need to "dial down" the charging current from 10 Amps to something lower.

Many folks here, including me, would recommend ToughLeads extension leads. They are expensive but are built specifically for use with the 'granny charger', can be used in the rain with a lockable socket. It has an optional RCD either in-line or part of the plug and they have also recently added a new "letterbox" option - it is a small inline plug & socket that will fit through a letterbox (a 13A plug won't fit) if you have a letterbox hole available rather than a window to feed the cable through.

I have used a 15m one with the inline RCD to a recently installed kitchen socket and it worked perfectly.

 

[Adopado]

Hi,
I’m planning on charging from a 3pin plug when I visit family at Christmas. I can park next to the garage so can get the UMC charger out of the rain. Am I then ok to run a standard extension lead from the garage to the house?
I can reduce the level of charge too if that’s advised as can charge overnight and will only need a top up. Obviously assuming the house has decent electrics and won’t trip.
Thanks!

It's common for domestic extensions with 13amp socket/plug to only be rated for 10 amps. Though you will only be charging at 10 amps this will be for several hours continuously so you really need an extension that's rated for the full 13 amps. If it's one on a reel it should be clearly indicated. (And any reel extension must be fully uncoiled as mentioned above.)

 

[DoricJim]

Try this from Screwfix. We were recommended this for our 13amp hot tub by the company (they took the socket end off and direct wired) and is plugged into our outdoor sockets. Works flawlessly and should handle charging a car?

PRO XT 13A 1-Gang Unswitched Extension Lead 10m - Screwfix

Order online at Screwfix.com. Heavy duty extension lead with single IP54 rated plug. Provides a safe and convenient temporary outdoor power source. Ideal for DIY and power tools. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

 

[marcovb]

Thanks everyone. l’ll look into those suggestions.

 

[Neilman]

Try this from Screwfix. We were recommended this for our 13amp hot tub by the company (they took the socket end off and direct wired) and is plugged into our outdoor sockets. Works flawlessly and should handle charging a car?

PRO XT 13A 1-Gang Unswitched Extension Lead 10m - Screwfix

Order online at Screwfix.com. Heavy duty extension lead with single IP54 rated plug. Provides a safe and convenient temporary outdoor power source. Ideal for DIY and power tools. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

Not dissing the Screwfix extension lead but you'd need to check it fits the moulded plug on the granny charger.

By all accounts the granny plug is bigger that your average mains plug and the Tough Leads extension notes that fact and provides a bigger housing to guarantee it fits when the housing lid is closed. That plus the optional RCD adds a bit of safety into the mix.

Of course if you do already have a sturdy heavy duty extension lead in your collection then try it first.

 

[Louis0w]

I have this from Tough Leads, which I'm very happy with: EV granny charger 13A weatherproof extension lead

 

[Overworked]

Thanks for the advice folks. This answers my problems and I have just bought the Tough Leads option with letterbox option.

 

[MrBadger]

Try this from Screwfix. We were recommended this for our 13amp hot tub by the company (they took the socket end off and direct wired) and is plugged into our outdoor sockets. Works flawlessly and should handle charging a car?

PRO XT 13A 1-Gang Unswitched Extension Lead 10m - Screwfix

Order online at Screwfix.com. Heavy duty extension lead with single IP54 rated plug. Provides a safe and convenient temporary outdoor power source. Ideal for DIY and power tools. FREE next day delivery available, free collection in 1 minute.

www.screwfix.com

Not dissing the Screwfix extension lead but you'd need to check it fits the moulded plug on the granny charger.

By all accounts the granny plug is bigger that your average mains plug

^ sort of this

The issue with the UMC dongle is that it is a very thick and non compliant cable. It will not bend easily (at all in some circumstances) to take up all but the straightest of cable routing in both the horizontal and vertical plane. The section of cable between its exit from the plug and where it passes through any weather seal is particularly short so even a small misalignment can be difficult to correct for - a particular issue for some switched outlets where the addition of the switch shifts the plug position to one side to accommodate. The thickness of the cable can also compromise any weather seal on the socket housing.

Another more subtle issue is that the UMC body can be twisted out of line with the orientation of the plug, so for instance a UMC placed on a flat surface may want to work against the direction of the plug/socket/housing, so if the UMC and the plug/socket are both flat then there will be some twist in the cable working against (normally) the plug/socket. Unless the cable exits the plug perfectly straight, this twist will start to work the plug out of the socket, potentially worsened by heating within the plug/socket. You may have a good connection at the start of the charge, but by the end the plug may have worked itself out of the socket a considerable amount. I posted a video of this occurring at some point on the forum.

I pointed this out to Adrian at ToughLeads when Tesla changed the design of the UMC with the introduction of the Model 3 in the UK. He assessed many different options before coming up with a socket/housing combination that allowed for a perfectly straight cable exit without any strain. I highly recommend ToughLeads as the attitude of Adrian in coming up with a perfect solution and retro applying the solution was exemplary. Certainly a company that I can trust.

 

[kael13]

I also bought a ToughLeads cable with the letterbox option. 5m should be enough but I'm now wondering if I should have gone for a little extra for the utility potential.

 

[DoricJim]

^ sort of this

The issue with the UMC dongle is that it is a very thick and non compliant cable. It will not bend easily (at all in some circumstances) to take up all but the straightest of cable routing in both the horizontal and vertical plane. The section of cable between its exit from the plug and where it passes through any weather seal is particularly short so even a small misalignment can be difficult to correct for - a particular issue for some switched outlets where the addition of the switch shifts the plug position to one side to accommodate. The thickness of the cable can also compromise any weather seal on the socket housing.

Another more subtle issue is that the UMC body can be twisted out of line with the orientation of the plug, so for instance a UMC placed on a flat surface may want to work against the direction of the plug/socket/housing, so if the UMC and the plug/socket are both flat then there will be some twist in the cable working against (normally) the plug/socket. Unless the cable exits the plug perfectly straight, this twist will start to work the plug out of the socket, potentially worsened by heating within the plug/socket. You may have a good connection at the start of the charge, but by the end the plug may have worked itself out of the socket a considerable amount. I posted a video of this occurring at some point on the forum.

I pointed this out to Adrian at ToughLeads when Tesla changed the design of the UMC with the introduction of the Model 3 in the UK. He assessed many different options before coming up with a socket/housing combination that allowed for a perfectly straight cable exit without any strain. I highly recommend ToughLeads as the attitude of Adrian in coming up with a perfect solution and retro applying the solution was exemplary. Certainly a company that I can trust.

I’ll try and see if the plug on the Tesla adapter fits the screw fix cable when I get a minute. Bummer if not as was hoping to sling my spare one of these in the frunk when I go on longer journeys to Scotland as a back up.

 

[Nujec]

Just seconding the recommendation of toughleads. I've used the waterproof modular EV extension lead with RCD to charge a Tesla Model 3 for hours at the full 10A and it stayed perfectly cold and fitted the large UMC plug fully closed for best waterproofing without problems. The modular connector fits through a letterbox easily. The domestic quality 13A extension I tried first got alarmingly hot within an hour. Great customer service from toughleads too, they really care about getting the product safe and right. It's a great lead to take on road trips and holidays in case granny charging is necessary.

 

[DoricJim]

I’ll try and see if the plug on the Tesla adapter fits the screw fix cable when I get a minute. Bummer if not as was hoping to sling my spare one of these in the frunk when I go on longer journeys to Scotland as a back up.

Okay so I checked and as suspected the socket cover of the screwfix lead won’t close due to thickness of Tesla granny charger 3 pin adapter cable. No use outdoors when wet then!

 

[Drew57]

I've been using this Masterplug lead with the UMC regularly since April 2020 when visiting my Father. Usually plugged in, charging for around 8 hours & taking care to ensure nothing is coiled or looped it has never been warm to the touch when unplugged (extension & UMC/plug both under the front porch so no risk of water ingress)

https://www.amazon.co.uk/gp/product/B0083GLMKU/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&th=1

 

[Neilman]

Okay so I checked and as suspected the socket cover of the screwfix lead won’t close due to thickness of Tesla granny charger 3 pin adapter cable. No use outdoors when wet then!

Sorry about that - we've been here before with long discussions on extension leads.

Your next experiment with the Screwfix cable should be to use it "in anger" to see if it will charge the car without overheating thus allowing you to use it as long as you keep it dry. So would be usable in a pinch.

Otherwise you'll be proven safest with a toughleads cable with the optional letterbox and RCD gizmo.