[James Watson]

Hi all

We currently have a 7kW pod point, but would like a back up in case it broke.

We are getting our consumer unit replaced shortly with a Hager RCBO / surge protection unit. While the electrician is here I want to ask them to run a new circuit for a second charging option.

I’m thinking to just ask for an outdoor 3 pin socket (in a covered side passage) for granny charging.

But, I want it to be future proof for upgrading to a second 7kW charger in the future. The cables will be going in the ceiling while it’s down so needs to be the right cable now as access will not be easy in future without making a mess.

Can 6mm cable be used with a 3 pin socket? Would you be expecting a 20amp RCBO to protect the circuit as initially installed with a 3 pin socket? The cable run is about 7-8 metres and will be partly in the ceiling running through joists and partly in plastic surface trunking.

Want to make sure I’m asking for (and get) the right thing!

Also, should I get anything else run at the same time, a data cable for example?

Thanks for your help

 

[electricdriver]

Why not get a 32A Commando socket fitted? Future proofs it and, with the Christmas offer from Ohme / Octopus on the Ohme charge unit at £149, you won't get a cheaper way of charging at 7kW. Lots of threads here about how to go about this, worth noting that if the purpose of the installation is primarily for EV charging then the regulations do say you need a separate earth to protect against neutral faults, or a device (e.g. Matt:E) that does that for you.

 

[Sputnik72]

Why not get a 32A Commando socket fitted? Future proofs it and, with the Christmas offer from Ohme / Octopus on the Ohme charge unit at £149, you won't get a cheaper way of charging at 7kW. Lots of threads here about how to go about this, worth noting that if the purpose of the installation is primarily for EV charging then the regulations do say you need a separate earth to protect against neutral faults, or a device (e.g. Matt:E) that does that for you.

Do you have a link to this offer, can't seem to find it on the website through My Account....

 

[Sputnik72]

Why not get a 32A Commando socket fitted? Future proofs it and, with the Christmas offer from Ohme / Octopus on the Ohme charge unit at £149, you won't get a cheaper way of charging at 7kW. Lots of threads here about how to go about this, worth noting that if the purpose of the installation is primarily for EV charging then the regulations do say you need a separate earth to protect against neutral faults, or a device (e.g. Matt:E) that does that for you.

No matter, I found it once I'd logged out of my account lol

 

[dk6780]

@electricdriver - good advice. An interlocked Commando socket installed to EVSE safety regulations is the best way forwards, and then use a conversion lead to 3 pin if you cannot justify an Ohme lead yet.

 

[Sputnik72]

Quick question, I'm currently charging using the granny cable on my 27kWh Soul, so charging overnight about 2-3 nights a week. I'm loathed to have a proper 7kWh charge point installed as I live in a rented house and could be leaving in the next year or so.. So could I get a Ohme cable and get an electrician to install a commando socket? If so would the cable be ok to be left outside while charging? If I did this would the car charge at 6.6kWh, my thinking is that it's a much cheaper option and I wouldn't be throwing money away If i did move house.... thoughts..?

 

[dk6780]

Whether you can change the electrics is down to the owner/managing agent. Will you save the cost during your remaining tenancy?

 

[James Watson]

Thanks for the ideas so far. Re the 32a commando idea, does the protection device have to be a separate “mini consumer unit” type arrangement like the matt:e suggested. Is there something that can go straight in the consumer unit instead for neatness? ie clips in where the rcbo’s normally go. Wouldn’t matter if this was oversized and took up 2/3 slots in the CU, I could just specify an 18 way instead of a 12 way.

The issue with a 32a commando vs 3 pin socket might also be the main fuse size at 80a. There is no load balancing in this set up. As well as the pod point there is a 7kw induction hob and double oven etc. We would never use them all at the same time but doubt the electrician would install the commando without our main fuse being upgraded by the DNO to 100a? (if the DNO would, I read somewhere Western Power were not keen on 100a fuses).

 

[Sputnik72]

Whether you can change the electrics is down to the owner/managing agent. Will you save the cost during your remaining tenancy?

The landloard would have no problem with me either installing a charge point or an outdoor commando socket. I was just thinking the Ohme solution would be cheaper and I could reuse it if I did move..

 

[Brian G]

The landloard would have no problem with me either installing a charge point or an outdoor commando socket. I was just thinking the Ohme solution would be cheaper and I could reuse it if I did move..

That is absolutely right. Seems as though commando sockets can be installed for £130 or thereabouts and the Ohme charger can either be fitted into a plastic box on the wall or less neat just hung on the wall. I have ordered an Ohme charger with a commando plug for getting a second car or for a speedy hook up if I need to relocate.

 

[mikegs]

The issue with a 32a commando vs 3 pin socket might also be the main fuse size at 80a.

From what you've said I think probably just go with a 13A socket for now, but get a 6mm cable run in for it.
Changing the bits on each end of the cable for any the future upgrade is fairly simple, and can be chosen to suit your needs, what is available and what the regs say at that time. But (re)running cable is a pain if it's not all exposed.

 

[James Watson]

Thanks Mikegs, as the 3 pin socket would be only used in an emergency or perhaps odd sunny days to charge on solar, do you think I can just have the 3 pin socket without any other safety devices? It would only be like anyone else granny charging from a 3 pin socket off the ring main in their garage. In fact it would be better than that as it would be a dedicated circuit.

I don’t really want to go to extra expense it is just getting the cable in really as you say. If I added a zappi in the future that would load balance. Just wondering whether I should run CAT5 or some other grade of data cable so something like a zappi could have hard wired clamps

 

[mikegs]

Just wondering whether I should run CAT5 or some other grade of data cable

CAT5 (6, 7, whatever they are up to now) isn't expensive, so probably worth doing at the same time. Make sure it has a shield as it's going to be sharing the run with a power cable.

 

[Mini]

Can't find the Octopus/Ohme Christmas offer of £149. Would someone please help me out?
TIA

 

[James Watson]

thanks Mikegs

 

[Leonids]

Can't find the Octopus/Ohme Christmas offer of £149. Would someone please help me out?
TIA

Shop

Welcome to the home of innovative smart charging for electric vehicles. Our solution helps you charge at the cheapest rate. Sounds good, right? Simple.

ohme-ev.com

 

[Mini]

Shop

Welcome to the home of innovative smart charging for electric vehicles. Our solution helps you charge at the cheapest rate. Sounds good, right? Simple.

ohme-ev.com

Thank you.

 

[proddick]

An interlocked commando is quite ugly outside and as a landlord I probably wouldn't agree. Also it isn't trivial or cheap to install an OHME as you do need either an earth rod or other protection in most supply cases.

For OP an EV rated 13A socket with larger cabling makes sense for occasional use. Dedicated 20A RCBO protected circuit is probably best approach.

Attached are notes on commando install from OHME

 

[James Watson]

Thanks Proddick. By EV rated 13a socket do you mean like the sort of thing you can buy from masterplug or Rolec, £50-100? Billed as level 2 changers with built in 16a RCBO’s, or do you just mean an IP rated outdoor socket by MK or similar.

It would indeed be a dedicated circuit with an RCBO at the CU

 

[Brian G]

Thanks Proddick. By EV rated 13a socket do you mean like the sort of thing you can buy from masterplug or Rolec, £50-100? Billed as level 2 changers with built in 16a RCBO’s, or do you just mean an IP rated outdoor socket by MK or similar.

It would indeed be a dedicated circuit with an RCBO at the CU

Just picked up on this. A good quality 13amp socket is all that is required. The load from the granny charger is 10 amps but because it will be carrying the load for hours it needs to have good contacts. A ring main can carry 30 amps so you can add the 13 amp socket to one if it is lightly used. Failing that a 4mm cable to its own trip in the CU is all that is required. The granny charger should have all the required safety equipment in it.

in truth the granny charger draws onl 10 to 11 amps.