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Hi All

We are currently waiting for some work too be done on the incoming supply by the DNO so have had to purchase a ev granny cable to use for the next month, it will only need around four hours a few times a week.

Last year we had a new consumer unit fitted and a dedicated double socket fitted to the rear of the house for cutting the grass etc… this is on B16 RCBO

We need an extension lead for the granny cable to get from the rear of the house to the drive of around 20 meters, we looked at the following on screwfix


TIME 3183P BLACK 3-CORE 1.5MM² FLEXIBLE CABLE 25M DRUM (729JY)​

13A FUSED TOUGH PLUG BLACK (68744)​

And then some recommendation for a single waterproof socket?

At the moment my daughters using public chargers but we’ve only got one local and she’s having to wait which I’d rather her not be sat in a car park at night

Any help would be greatly appreciated
 
You don't get any 13A sockets that are really, totally, all-orientation waterproof. This is the closest you will find and you would also need an IP68-style plastic cable gland for entry and sealing clamping:
https://www.screwflix..com/p/britis...dp-weatherproof-outdoor-switched-socket/35096

They are not really suited to be used as a general-purpose trailing lead in the wet, they ought to be kept in a nominally upright orientation but you can probably make a small wooden support to allow that.
 
Thanks for the reply, I could strap the socket box to a fence to ensure it’s vertical and away from the ground.


Does the above all seem ok regarding the double socket on a B16 RCBO and would you see any reason for concern having a 20 meter cable cable run for the extension lead.

Thanks
 
It is not unusual to see 25m extension leads in 1.5mm cable, not an issue so long as properly made up.

Ideally you should use something like this to verify all wiring is as expected, and that the test button trips the RCD as it should. Any outdoor socket must be RCD protected.
 
Ideally you should use something like this to verify all wiring is as expected, and that the test button trips the RCD as it should. Any outdoor socket must be RCD protected.

Apologies but all I can see is a double socket on the outside of the house and the RCBO in the consumer unit, will this be the protection required or do I require something else

On the B16 RCBO it says 30mA if that helps

Thanks
 
Last edited:
Is the EV a hybrid and does the manual state that a 13 amp supply is enough for charging ?
 
I occasionally use a similar setup to charge my van... it works fine, but I'd keep an eye on things the first few times to make sure there are no bad connections that cause things to get too hot.

Theoretically... you should be using 13A sockets that are "EV" rated as these are designed to be used for a high load for long periods of time.

Some (maybe all ??) "Granny Cables" have in-built temperature sensors in the 13A plug tops that will trip out if getting too warm... but your extension cable will introduce new connections points that won't be temperature monitored.
 
Do I need to check the plugs and sockets or do I need to check the consumer unit for heat as well?
The CU should be fine if properly installed.

Just check the 13A plugs are not overheating. New sockets of decent quality out to be OK, but any loose-fitting plugs or tarnished connections can cause problems on sustained high loads.
 
The cable will only have around 1 meter play so it won’t be coiled up, it all sounds scary when you think about it.

hopefully it will only be a matter of weeks and then it will just be an expensive extension lead that probably won’t get used.
 

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