Ohme charger install question

MaryWhitehouse

Well-known Member
I’ll try and explain this clearly but apologies if not. I can get more pics or a diagram later.

My Mrs has ordered a Mokka-e as her next Motability car, which will arrive one day! As part of the lease Motability contract Ohme to install a charge point, who in turn sub-contract AES-Charge to install.
What I’m trying to determine from you learned folks is if the install is actually different at our home or just a slight change. AES-Charge have said it’s non standard with an extra charge but won’t discuss with us. Motability are trying to sort it out.

We live in a rural rented property (with permission for the install) which was a farm. If you imagine coming up the drive, at the top the meter shed (farmyard still has a three phase install) is about 10m to the left and our house is about 10m to the right. Obviously, at least I think so, there is a cable between the meter and the consumer unit which is in a kitchen cupboard at the nearest corner of the house. The charge point needs installing on one of the walls on the outside of this same corner.
AES-charge seem to think (but won’t discuss with us) that they need to charge for a connection at the meter end and cable and trench to the house.

My question is do they need to do this? Can’t the charge point connection be at the house end of the cable between meter and house, not the meter end. This would obviously negate the need for the extra work.

Thanks all.
 

Thatsnotmynaim

Distinguished Member
Many chargers are installed directly from the meter box as it's much simpler and does not rely on the exisitng CU or its cable to it being checked or of a certain type.
If this cable between meter and charger is over 15 meters then they often charge extra for more cable, but usually the new mini consumer unit is already within the cost. Obviously any trench work will usually be chargeable.
My install was done from the infeed of my exisiting consumer unit, so on the live input side
My neighbours installer refused to do this and instead insisted if it was to come from the the meter or if from the existing consumer unit then he would have to pay and get an electrician to install a spare trip of certain rating and type before they would start work.

I think it varies massively between who plans and does the work and different companies have different standards and ways they prefer to do things.
With my neighbours which I was helping with, the planners where very awkward about what they would and wouldn't do, they wanted everything installed outside including the new mini CU and would not entertain running the cables and mini CU inside the garage. In the end I said whatever to them and to plan is as they wanted and if ok I would just talk with the installer at install time to see if he could do it any better way. When he turned up he said he couldn't undertsand what the planners were going on about and would install it exactly as per what I had said so from the back of the meter box into the garage, new mini CU inside, all the canle run 12m inside the garage at high level and then pop through the wall and outside into the back of the charger.
 

MaryWhitehouse

Well-known Member
Thanks :) if the house was less than 150 years old it might have a meter cupboard externally but they’re fairly rare except for new builds round here. I think a lot of the problem is as you allude to that the companies are still hiding behind covid to save costs and if someone qualified did a physical survey it would be fairly simple to rectify. If they want to put everything by the meter then run a cable to the charge point I think we’ll fail as the landlord will lose his sense of humour.
 

AMc

Distinguished Member
Any pictures of the existing CU and the meter box?
My guess is that they're unsure of the cable between the meter box and the house or unwilling to risk it not being up to the load.
By insisting they connect at the meter end and use new cable they can be sure that everything will be OK. Your power company will be responsible to the meter and they will be using all new stuff from that to the charge point.
It does sound like jobworthing but I can see why they might be thinking this.

In my experience every electrician who's visited my (200yr old) house has sucked their teeth and called every other electrician who's worked on it before a cowboy. I appreciate the regs get tighter year by year but there's a difference between "meets todays regs" and "inherently lethal" ;)

Have you tried getting a quote from another charge point company to see if they have the same objections?
 

MaryWhitehouse

Well-known Member
Any pictures of the existing CU and the meter box?
My guess is that they're unsure of the cable between the meter box and the house or unwilling to risk it not being up to the load.
By insisting they connect at the meter end and use new cable they can be sure that everything will be OK. Your power company will be responsible to the meter and they will be using all new stuff from that to the charge point.
It does sound like jobworthing but I can see why they might be thinking this.

In my experience every electrician who's visited my (200yr old) house has sucked their teeth and called every other electrician who's worked on it before a cowboy. I appreciate the regs get tighter year by year but there's a difference between "meets todays regs" and "inherently lethal" ;)

Have you tried getting a quote from another charge point company to see if they have the same objections?

I can see why someone can't visit would think that and opt for the 'safe' option. The supply and house wiring isn't too old (1998) and was checked for landlord certification just before Covid. Because of Motability it's these people or none. That said Motability are generally excellent to deal with.

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AMc

Distinguished Member
I can see that might scare people off! I'd clean up the spider webs for the next set of pictures if you can.

Is the top picture the meter shed and the next one your house meter?
If that's your meter then who owns the connection back to the meter shed 10m away - the landlord?

It looks to me that you have several spare slots in the CU and based on the labels not a load of huge current draws - but I'm not an electrician and that's who you need to trust :)

For mine the installer just fitted a new breaker in the board and wired off that - I also have a 3 phase supply - installed 2008/9

If you have the authority to have your meter upgraded to a smart meter then that might demonstrate to the installers that the cabling is fit for purpose - just thinking out loud on that one?

If the installer are making you pay the extra for the trench, cable etc. then it might be economic to just pay for an install from someone else. I didn't pay for any quotes for mine though it was all online.

I can't see how motability can object to using an "existing" professionally installed charge point when they deliver the vehicle but I've never had to deal with them.
 

MaryWhitehouse

Well-known Member
The first two pics are in the meter shed. The meter you can see next to the fuse in the second picture is separate, for the farmyard supply. The same landlord owns the whole property. House, yard and land.
I agree about the smart meter but my supplier (who I can’t change because of the landlords supply for the yard, never have got to the bottom of why) has none to fit at the moment or for some time!
I agree about another supplier in general. If it comes to it I’ll see what the economics are but turning down essentially free one I’m not sure yet.
Thanks.
 

noiseboy72

Distinguished Member
You may find that the company are unhappy with the earthing arrangements and need to check these over. They will normally fit to houses with PME, so will fit an additional earthing point next to the charging socket. 3 Phase is a different kettle of fish and if they decide they need to fit an earthing rod, they may need to make this of a size to protect the entire installation, not just the car.
 

MaryWhitehouse

Well-known Member
You may find that the company are unhappy with the earthing arrangements and need to check these over. They will normally fit to houses with PME, so will fit an additional earthing point next to the charging socket. 3 Phase is a different kettle of fish and if they decide they need to fit an earthing rod, they may need to make this of a size to protect the entire installation, not just the car.

That kind of thing I can accept. Again it’s why a real surveys needed.
 

AMc

Distinguished Member
I agree about another supplier in general. If it comes to it I’ll see what the economics are but turning down essentially free one I’m not sure yet.

That does sound like a pain to sort out.
Depending on the mileage you do then you might be able to manage with the granny charger and/or fast charging away from home?
3 hours on the granny gets 20 miles or so real world range on my GTE - dragging around a petrol engine :)

This says their Pro charger has built in PEN fault detection - if your installation is PEN.
Mine is and has labels on the incoming supply to indicate that.
 

MaryWhitehouse

Well-known Member
Tbh most of the time a granny charger at home would work ok along with boosts from free ones at supermarkets while out and about. Maybe not the 350kw one that’s been installed not too far away! The car is at home most days and overnight.
Just need a proper outdoor socket installed lol.
 

AMc

Distinguished Member
I'll refer you to my experience in the thread linked up above. There's a very detailed discussion of earthing - make your own judgement on that I won't get back into it again!

I did granny charging for the first 6 months and it was fine but if you can work out a secure, weatherproof place to keep it ready to go that will make it much easier.
The VW granny is 6m long end to end with a big power lump in the middle and different thicknesses of cable. That makes it quite awkward to handle esp. in the dark & rain and if your drive is as muddy as mine. I got quite good at coiling it all into a plastic box but it is still much nicer to just plug in with one cable - though a 10m type2 to type 2 is also quite heavy and awkward to manage and I need to wash my hands after plugging or unplugging.
 

MaryWhitehouse

Well-known Member
Thanks I’ll have a proper read of that shortly. In some respects are situations are similar in that the car must be outside and it’s an old property. Electrically I have no idea as my tame spark passed away so not answering questions lol. I’ll read your other thread shortly.
 

noiseboy72

Distinguished Member
There's a specific risk around charging electric vehicles using the mains supplied to the majority of UK homes.

It stems from the fact that the earth is derived from the neutral connection. The neutral is joined to the mass of earth outside of the home at multiple positions, but if the neutral was to fail after the last of these connection points, the house Neutral AND Earth will rise to the Live line voltage. Inside your home, this is not an issue, as you have no reference to the mass of earth, so little risk of anything more than tingling taps.

Things are a bit different with anything outside of your home, and a big, metal box sat on its rubber tyres will be sat there at 230v with reference to the ground around it.

RCDs and RCBOs will not provide any protection against this sort of fault, so chargers have either an earth rod and separation from the household earth or has a PME fault detection circuit.

If you use a granny charger from an internal or unprotected external socket, you do not have any protection from PEN failure, so there's a small risk of electrocution.

The same risks apply to caravans, hot tubs and incorrectly installed out buildings etc.
 

MaryWhitehouse

Well-known Member
There's a specific risk around charging electric vehicles using the mains supplied to the majority of UK homes.

Thanks, I've read the other threads. Any thoughts on the original question?
 

noiseboy72

Distinguished Member
Thanks, I've read the other threads. Any thoughts on the original question?
As already posted. I think the complications of the 3 phase to property might be their cause for concern. They may want to check the cable type and capacity, along with the earthing arrangements.
 

AMc

Distinguished Member
I assume you don't want to or can't install the charge point at the other end, park near to it or use a long cable when you need to charge?

As you live in a rented property your install should still qualify for the grant - have you discussed that with the installer, does that help with the cost?
 

MaryWhitehouse

Well-known Member
I assume you don't want to or can't install the charge point at the other end, park near to it or use a long cable when you need to charge?

As you live in a rented property your install should still qualify for the grant - have you discussed that with the installer, does that help with the cost?

Unfortunately not. That's 'his' bit and would get a tractor parked on it!

I noticed that but not applicable in this case as Motability pay the whole cost. Thanks :)

Have thought of a number of alternatives if needed such as pay for spark to properly install either a 13a 3 pin or 32a commando outdoor socket and buy the appropriate leads. For 3 pin I looked at the Masterplug that I think you bought and the Ohme one. I think there's heading towards £300 difference and the main difference is viewing through an app. From your experience, given the Vauxhall doesn't share the API, is there any real advantage to that for all that money?
 

AMc

Distinguished Member
The reason I mentioned it is the installer may not be aware that they can claim the grant?
Might sweeten the deal for the Ohme people to cover the extra cabling cost if Motability are paying the "flat fee" for a standard home owner install but they can also get the £350 govt contribution.

If you use a 3rd party and swallow the cost yourself, then it's £350 off for you/your landlord.

I started with a 3 pin external socket - from Screwfix and installed with the help of a mate.
Used the VW granny charger though I considered a 10m Masterplug one from Screwfix to make it easier to plug in.

Later I got an EO Mini Pro2 installed.
It has a "smart app" which was required for grant qualification.
The app is very basic and I just use it to track the power consumption of charging the car.
I don't have solar.

The EO app is not bright enough to know the difference between an "EV plugged in" and an "EV charging" so it's charging times are always mad, but you can see when the box is or was actually supplying juice to the car.

I use the car itself to schedule charges - I tell it I'm leaving at 6.59am every day and that I have off peak power 12-7am so when it's plugged in it schedules its charge ahead of that departure time.
Given the price of power I'm keen to use cheaper off peak as much as I can.

I wouldn't have bothered with a "smart" charger for my car. I understand from here that other cars are not as easy to set up and schedule.
 

MaryWhitehouse

Well-known Member
The reason I mentioned it is the installer may not be aware that they can claim the grant?

They won't even talk to me lol.

I use the car itself to schedule charges - I tell it I'm leaving at 6.59am every day and that I have off peak power 12-7am so when it's plugged in it schedules its charge ahead of that departure time.
Given the price of power I'm keen to use cheaper off peak as much as I can.

Thanks. No off peak for us. Tbh all I need is a charger I know will switch off when done.
 

neilball

Well-known Member
Note that the electrical regulations regarding earthing arrangements and electrical safety for EV charging require to any circuit that you use to charge outside, whether that be a 13A socket, commando socket or dedicated unit like the Ohme. So you still need either an islanded TT earthing arrangement or open PEN protection, and the correct feed for the circuit with the correct type of double pole RCD plus MCB or RCBO.

Normally this all means not taking a new circuit from an existing consumer unit, especially as that might require lots of additional test and rectifications to the circuits connected to that CU if it is to be “modified” by the new circuit installation. That is why nearly all EV charger installs are taken off the supply at the meter and use a new small wdeicated consumer unit for this new circuit - this has no impact or requirement to touch/test the rest of the electrical installation.

So you are in a position of having an unusual supply arrangement, and with the age of your existing consumer unit that may be putting off the installation company from considering using it.
 

MaryWhitehouse

Well-known Member
So you are in a position of having an unusual supply arrangement, and with the age of your existing consumer unit that may be putting off the installation company from considering using it.

Unusual? The tail between the meter & CU is just very long.Why can't the supply for the EV be taken off at the CU end of the tail rather than the meter end? It's no different to normal just with more cable before it.
 

noiseboy72

Distinguished Member
There's a number of reasons why not. Unable to ascertain the condition of the cabling, insufficient cable size, insufficient spare capacity in the CU, size of Neutral in 3 phase installation, calculated balance of phases following installation... The list is long!
 

MaryWhitehouse

Well-known Member
There's a number of reasons why not. Unable to ascertain the condition of the cabling, insufficient cable size, insufficient spare capacity in the CU, size of Neutral in 3 phase installation, calculated balance of phases following installation... The list is long!

I’m still not sure what the difference is at one end of the tail to the other?
 

neilball

Well-known Member
I’m still not sure what the difference is at one end of the tail to the other?
It’s an issue because you supply goes straight into your existing CU, so they would have to disconnect the supply from it, add the necessary switchgear to separate out the feed with some new tails into the new CU for the EV charger, and put tails back into your existing CU. This then means testing your CU, which could uncover issues that need fixing (at your cost) before they can sign off the work and give you the required certification. If they come off at the meter wide they are only breaking an existing supply cable or connecting to existing terminals, which has little or no risk of unknown issues at test time.

It’s one of the issues dealing with existing installations - find something seriously wrong and you are now responsible for making sure it gets fixed, or having to make the system safe until repairs are made, which could leave you without power if you disagree with rectifications or costs involved. So that’s why most installers do not want to go anywhere near an existing CU, no matter how easy it might make things in the home owners eyes, as it avoids these difficulties.
 

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