Fitting an outside socket for charging hybrid car

Just one further point of clarification flameport if i may
You mentioned early on in the thread :

Would it be acceptable for me to lay the cable and do the donkey work and capture video evidence for his review (photos under the floor) and then he simply does the work on the cable work at the CU end, the socket and the isolator and tests ?
Its going to be a faff getting floor boards up, moving bedrooms around hence my hope was to have the cable laid ready

Thanks again for your continue input....much appreciated (y)
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There are many ways to run cables, personally I prefer steel wire armoured (SWA) outside or where damage likely, but other will prefer steel conduit, neither is wrong, it is personal preference.

If a cable is hidden there are safe routes, but you can use special skirting boards to take cable, upload_2022-1-30_15-14-33.png main reason for not using it, is it is rather expensive, but the option is there.

I have not gone back over the 4 pages of replies, but as far as inspection and testing goes, it can cost as much to get some thing signed off as the whole job costs, in Wales using the LABC minimum charge is £100 plus vat, and they can also charge you with cost of a third party electrician to do an EICR which they use to issue the completion certificate.

My son for a short time worked as a sole trader electrician, and he when he started got a few requests that the owner could do some of the work, which to start with seemed fine, but then he would turn up to find work not done, and very quickly he realised this was loosing him time and money so stopped doing it.

So finding an electrician who will let you do some of the work is rare.

I've got a similar project in mind, but with a different source. I have a shed with separate supply and MK consumer unit. The earth is to the supply metal sheaf, not neutral. It supplies power to garden lighting and a couple of power points, all with appropriate armoured cables. I'm wanting to add a 16 commando socket for external car charging.

So far i've got as far as needing a 32amp MCU PME Fault Detection Distribution Board fed from a 32 amp fuse in the consumer unit and a 16amp latched commando IP 44 socket outside within a wooden box. 2.5mm cable running within the shed through a hole to the commando socket.

I think, which is why i'm asking, that the PME board takes care of any potential DC leak and the 16amp charges the car over night.

My questions are:

Can I ( or my sparky) connect this to the same 32amp fuse as an existing single 3 amp socket ( in the shed) and how can I tell whether the current RCA isn't going to cause problems. I've read that having the wrong type of RCA causes problems, as there's one in the PME unit. i'm hoping its either ok or i can charge the consumer unit RCA.

While i'll fit it all together my sparky will terminate, having checked my wiring.

There are 3 diffrent supply types, TT, TN-S, and TN-C-S also know as PME and most of the problems revolve around the latter.

Even with the latter where a vehicle is being charged in doors it is still not a problem.

The disconnection of an earth goes against the grain, and to do it one must ensure lives are disconnected first, and until the EV if TN-C-S was likely to cause a problem it was banned, as with caravans, boats, and petrol stations.

However with a caravan fire regulation give a minimum distance to a building, so where the vehicle is parked will change what is required. With my house there is enough room to have a TT supply for car and TN-C-S for house.

But each home needs assessing as to what is required.

There is no quick answer, same goes for DC with RCD protection.
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Good points.

From my research I think the supply is TN-S, which I should have mentioned ie the earth is not connected to neutral but to the shield of the supply. I think that's good for my purpose as I don't need a new earth spike and the PME will operate as desired. i'm a bit confused around the type of RCD fitted though to the consumer unit. it's a MK 7860, though it's not clear to me what sort of RCD that is.

Truth is i should probably ask my sparky to add a new tail from the supply, just for this purpose.
It seems looking at averts it seems that the MK 7860 is a 63A Sentry 2 pole 30 mA type AC RCD.
Type AC sign

Type A sign

Type F sign

Type B sign

In the main chargers have a built in 6 mA DC trip and so type A
is required, some don't and need type B
which is rather expensive. 63 amp seems rather low when the charger will be on for an extended time, and should only be fitted if either the supply fuse is 60 amp or the total of the MCB's on the RCD does not exceed 60 amp, it is common for the wrong size to be fitted, as they came with the consumer unit, not a clue why, as cost of a 100 amp RCD was very little different to a 63 amp.

As to TN-S or TN-C-S only the DNO can tell you what you have, TN-C-S means some where between the transformer and you earth and neutral are combined, it does not need to be combined at your house.

I would say you need to get your sparky to do the whole job, it is rather complex.
This started with me wanting to install a 13amp socket to run a standard grannie charger. it quickly progressed to the idea of a 16amp commando style socket as a spur to the existing shed supply to give 16amp charge rather than 10amp on the grannie. Then I read about possible problems of earthing.

It's worth noting that all the shed supply support are a dozen LED lights and a couple of rarely used sockets in a shared garden, so perhaps 0.5 amp load. As I say there's a separate supply and consumer unit to my domestic supply.

I was looking at a Garo 32amp MCU PME Fault Detection Distribution Board, their G6EVPME132 but wondering how to connect it to the consumer unit. I think its either a new tail from the supply side of things, effectively a secondary consumer unit, or to wire the Garo into the existing unit, recognising the potential RCD confusion. I see MK can supply a type A RCD.

I would certainly have my sparky provide the service. I'm just interested, in avoiding unnecessary cost or getting ripped off.
This started with me wanting to install a 13amp socket to run a standard grannie charger. it quickly progressed to the idea of a 16amp commando style socket as a spur to the existing shed supply to give 16amp charge rather than 10amp on the grannie
What is a grannie?
It’s the term used to describe charging a car from a 13amp socket. I think it’s come from taking a trip to see grannie, then charging the car from her house 13amp socket
The Garo G6EVPME132 is a single-phase MCB and PME fault detection distribution board that provides protection against electric shock by disconnecting the electric vehicle under charge from the live conductors and the protective Earth of the supply within 5 seconds of a supply fault voltage being detected.
the data sheet says nothing about DC detection.

There are two completely independent problems with a supply to an EV.
One is the earthing arrangement, and it seems a device is used so if the voltage is not within the 207 - 253 volt range it completely disconnects the supply, other methods can be used, like an earth rod so it measures supply earth compared with true earth, or of course simply don't use supply earth, however then looking at enough distance between the two earthing systems so can't come into contact with both.

The 207 - 253 volt method clearly has a problem if there is no auto reset, and any brown out could mean no charged car when required. The data sheet shows
and a copy of 722.411.4 from BS 7671:2018 amendment 1, it would seem there is auto reset
not sure about this, as if PEN is lost then don't really want the unit to be reconnecting all the time, this seems wrong?

The 6 mA detection is completely independent, many units
have the 6 mA and even a RCD built in, but not all, so one needs to read the spec. The one show says

  • Rated voltage: 230V AC
  • Rated current: 32A
  • Number of phases: single phase
  • Maximum charging power: 7.2kW
  • EV connector type: Type 2
  • Power plug: Industrial 32A CEE single phase
  • Total cable length: 5m
  • RFID cards: 2 (only for settings adjustment, no lock function available)
  • Ingress protection level: IP 54
  • Operating Temperature: -30℃ ~ 50℃
  • Standards: IEC62196-2 Sheet 2-lla / IEC61851-1 / CE
note nothing about 6 mA DC disconnection, so a type B RCD would be required unless IEC62196-2 says different.

As to "granny charger" it really does not matter if charge rate can be set to 8/10/16/20/32A. as shown or fixed at 10 amp, the major problem is by fitting a 13/16/32 amp plug to the unit it can be used on an inappropriate supply type. It by passes the rules, not the problem.

I for one feel it is only a matter of time before some one is injured and we have a knee jerk law passed which will likely go OTT, and we could see with some luck PME banned. But in the past when for example fires have been caused by PME supplies loosing the PEN it has been blamed on copper theft not use of PME, so who knows.
There is always the possibility of faults.
Devices which can create DC faults can't be installed downstream of a type AC RCD, as those DC faults won't be detected and can stop the RCD from working for AC faults.

The most obvious solution is to have a new circuit for the outdoor socket from a Type A RCBO, installed into the spare #4 way in the consumer unit.
20A isolator switch inside if desired, and a single unswitched socket outlet outside.

Hi again flameport....apologies for the delay and yet more questions

As advised, i purchased an unswitched BG socket to swap into the housing, but as you can see from the pictures, the profile is significantly different and doesn't sit flush inside
The switch that came with the outside socket is very slim and profiled as you can see here (the left hand one) :

...whereas the standard BG is a square and chunky affair :


I've scoured the internet and it doesn't appear that BG do a slim/same profile unswitched socket equivalent
There are a couple of other possibilities (a Schneider and an MK) at screwfix so i'll give those a go but if they don't fit/aren't suitable :

  • just how much of a deal breaker is it needing to be unswitched, ie, is it just a case of you don't need it so don't have it, or would a sparkie not sign it off as it is switched ?
  • the Type A RCBO....i assume that that just needs to be >= 20A ?

thanks again for all your advice to date, its much appreciated !
It’s the term used to describe charging a car from a 13amp socket. I think it’s come from taking a trip to see grannie, then charging the car from her house 13amp socket

Its like tales of a modern day red ridding hood, young lady visists her grandmother, travelling there in her little red EV and plugs in, greets her grandmother, sits down for a cup of tea and discusses topical news items, the weather, household expenses and then "Oh my granny, what a big electricity bill you have".....
I was looking at the charging rates, it seems using DC can be a massive charger rate, but using AC many cars can only charge at 7 kW even when plugged into a 22 kW three phase charging point.

On another thread this
was posted, and it at 19.22 minutes does a chart on range.
60 MPH all systems off 231 miles range.
70 MPH all systems off 200 miles range.
70 MPH all systems on 146 miles range.
70 MPH all systems off and 4 passengers 192 miles range.
70 MPH with sky rack 162 miles range.
70 MPH with roof box 177 miles range.
70 MPH with roof mounted bike rack 169 miles range.
60 MPH towing caravan 100 miles range.

It says 318 miles according to Skoda with the version tested, and it was tested with no hills or change in speed.

It has a 77 kWh battery, which is a handy number as 77/7 = 11 nice easy maths, so needs at least 11 hours to charge from flat, and it will only charge at 7 kW even with a 22 kW charge point as only uses a single phase.

Looking at a 10 amp granny charger then 33.5 hours, how long were you going to stay at your grannies?

So typical for me is three trip lengths, 25 mile local shops, 50 mile youngest daughter, and 100 mile other two children. The latter is seems likely a problem. Even if I plugged in at other children's houses stopping there an hour 2.3 kWh is not going to extend the range much. No DC charging points on the route, so would need to use an AC charge point at 7 kW, but no way do I want to wait 11 hours for it to recharge, even with a three phase charging car it would be over 3.5 hours, that more time than I want to spend twilling my thumbs.

So they are simply a non starter. Compared with diesel car I drive now, I can do three trips to children and re-fuel in 10 minutes or less.
This is how my ev charger is installed and it passed NICEIC site visit.

hi Swwils

can you confirm if your outside socket is unswitched please ?

I’m curious because I am following the advice kindly shared by flameport, but I’m struggling to find a replacement BG unswitched switch, to replace the switched one that came with the original socket


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