Popcorn at the ready

 

Have a number of "we use granny charging daily with no problems" posters dissapeared or started to keep quiet since the fire?

Maybe it's just me noticing things that aren't.

Gaz

 

I think my mother has come round to an electric car, a Volvo XC30.

She will solely be charging at home as she doesn't travel too far and only covers 5-6,000 miles a year.
Her garage is quite a distance from the house and the mains board. The garage has a supply but won't manage 7kW.

Can the XC30 be charged every night on a "granny charger" from a 3pin socket?

The short answer is yes.

But there are caveats, and it's not recommended for a few reasons. There is a well reported but rare risk of what is called a PEN fault. Quite rare but it can be dangerous. Search PEN fault in the "Search Community" box above. Easily solved by converting the garage supply to be earthed using a ground spike. ( If it isn't already) And a change to the trip that supplies power to that socket will overcome another risk. A local sparky will carry these out fairly cheaply.

Or she could just use the existing 13 amp 3 pin socket to plug a granny charger in, without adjustment - just like many thousands already do without any concern or issue.

 

Many thanks.
I think the garage is earthed with a rod, I need to check.
It's a large garage with it's own mains board, I think 2 or 3 breakers, with several twin sockets inside the garage
13A 3 pin is preferred as it's easier for her every night to plug it in (she will be on Octopus Go).
Also , I don't really want a wall box, it's something else needing an app and more potential problems. I'm trying to simplify this as much as possible for her.

 

I think my mother has come round to an electric car, a Volvo EX30.

She will solely be charging at home as she doesn't travel too far and only covers 5-6,000 miles a year.
Her garage is quite a distance from the house and the mains board. The garage has a supply but won't manage 7kW.

Can the EX30 be charged every night on a "granny charger" from a 3pin socket?

Yes, but just because you can should you?

My first port of call when considering this is to ask my home insurance provider, I'm fairly sure I know what the answer would be.

 

For AC charging on a 3 pin plug the Volvo (Skoda's have it as well so I assume it's a common feature) there is a setting in the Car to restrict AC charging to 2kw or around 9 (ish) amps. Rather than allowing the car to draw as much as it could do. From what others have told me on here it is the car that controls the charge not the lead. Some leads claim to supply up to 2.4kw which can be beyond 11amp. A standard 13amp socket is not expected to be used at 13amp continuously.

Using the 2kw capacity a five hours overnight tariff could add around 30 mile range. Will that be enough?

A 7kw supplying wallbox can add around 21 miles in an hour.

Volvo manual for the setting if you are happy with all the other caveats that people will quote on the forum.

EX30 Setting the amperage limit for charging | Volvo Support UK

Volvo Support for EX30 Setting the amperage limit for charging | You can set an amperage limit for AC charging by selecting a value in the charging view.

www.volvocars.com

 

From what others have told me on here it is the car that controls the charge not the lead. ]

No, it's is the charge point/EVSE that sets the maximum current that can be drawn, not the charger in the car. The charger has to always stay at or below the maximum current that's advertised by the charge point. In the case of UK safe portable charge points (a.k.a. granny leads) this maximum advertised current will be 10A, the maximum safe continuous current rating for a UK 13A plug (the 13A is the maximum short duration current rating). The charger in the car can run at a lower current than the maximum but can never exceed the max current that's being advertised.

 

The garage has a supply but won't manage 7kW.

Would it manage 3kW ? I think there are 3kW chargers as well, maybe a bit cheaper, ? can someone who knows a bit more explain....

 

Yes, 16A (or 3.6kW) is a common standard for charge points where the house wiring has limited capacity. My Chargemaster had a jumper setting to switch between 16A and 32A. Some early EVs wouldn't charge faster than 16A too.
It won't make it much cheaper, but a properly installed EVSE, limited if necessary to 16A, is the best solution.

 

You missed the point
OP considers charging every night on a granny is going to be good for mother, compared to charging once every 3 weeks on a proper,safe EVSE

 

As the plug seems to be the weak point for granny cables is it possible to hard wire the cable into the socket?

 

Perhaps something like this would be a better solution. It would require one of the 13amp sockets to be converted to a commando outlet. And an electrician would then have to comply with the usual EVSE regs as the socket was clearly to be used to charge a car. However, it would give a variable charge rate of up to 16amps rather than 10amps. And use a safer plug. There is a hint of delayed timing in this unit as well.

Type 2 to 16A Commando Plug, EV Portable Charger, 6A - 16A Variable, 3.6kW, 5 Metre

 

We’ve had 7 full EVs since 2018; Granny charger always, plugged into a socket in the garage, no 🔥 yet!! 🙂

 

@Peirpoint There we go... the first one. Mind you... it took longer than of late.

 

I understand the EX30 works in the same way as our XC40. You can set a maximum charge current in the central screen. Anything from 2-32 amps in 1amp increments. It's possible to restrict it to 6 amps instead of 10 if using a normal 3 pin socket.

 

This is the problem with doing risky stuff.

Risks rarely impact 100% of the population of anything. Take smoking. I would guess that everyone now knows that smoking has risks, including cancer and heart and lung disease, and that the risks are serious (as in life-limiting or fatal). There will always be some who will argue it's not a risk because they've been smoking for X years and haven't (yet) got ill from it or died.

Running heavy loads for long periods from a 13A outlet is much the same. We know there is a risk, the evidence that plugs and outlets overheat when used in this way is irrefutable, but some will always say they've got away with doing this for years.

Just because some have been lucky and not had a problem doesn't remove the risk.

 

By now the OP will be wondering what hornet's nest he has stepped into by seeking to use a commonly supplied piece of equipment to charge an EV. Threads like this inevitably see a post like #27 sooner or later. And also many warnings about the use as a permanent solution.

The point is that the 'granny' name came from the intention for it to be used when visiting granny in deepest mid Wales a couple of times a year and as an emergency method to grab a few miles to get the EV back to a 'proper' charger. Even then the session must be supervised and with constant tests of the plug/socket to check for heat build up. And certainly never used overnight with people asleep in the same building.

The potential issues have been mentioned already. The OEM making the kit know of the dangers and install a heat sensor in the plug to cut power if heat builds up too high for safety. That fact alone should alert people intent on using it daily and cause them to reconsider. It's fine for occasional supervised use. But not for a permanent charge method.

And that is without mentioning the safety regulations that exist when an electrician installs a circuit that is known to be designated to charge an EV. A random socket in a remote garage that has been there for thirty years can hardly be said to comply with those regulations. It will probably be fine - until it isn't. Personally, I would consider spending a bit in order to comply with the safety regulations is the way forwards. Especially when considered alongside the capital cost of a modern EV. Perhaps that's just me.

I 'get' the desire to make things easy for a new elderly owner. But plugging a 16 amp wall mounted EVSE tethered lead plug into the car is in fact identical to using a permanently plugged in granny charger. And safer. And gives more range within a night tariff. It will cost a bit. Of course it will. But is it really something to penny pinch on?

Threads like this always go around and around with people saying they have always used a granny, and others giving dire warnings. The point is that it has always been regarded as an emergency method. For good reason. So that if people decide to just use it sparingly in a situation where only 25 miles a day is required then it will probably be fine. With the caveat that one random day/night it might not be fine.

 

Just on the roof at the moment, pissing into the wind
More productive use of my time I think

 

Friend of mine got the EX30 - largely because they need 4wd - and hate it (they didn't test drive).

Main irritant is everything having to be controlled from the central screen.

 

Interestingly I walked away from it because of that. I have fingers that don't produce action on touch screens so I need buttons if I am not to be distracted. I had the audacity to write to Volvo and tell them it was a rubbish way to set up a car. They thanked me for my views... . Then the motoring press got their hands on it and said the very same things. In my view the car is unsafe, the speedo is offset and if you wear varifocals your are screwed.The sweet spot for reading is down and not to one side. And then there was the lady driving a Volvo who in trying to use a touch scree to turn the heated steering wheel heater on drove head on into another driver and killed him.

Don't let the IT boys loose on something and break what has developed.

 

The pen fault problem has been around for decades. Most folks never came across it until ev's turned up leaving a big hunk of metal on the drive.
Those with a metal greenhouse and a power socket in it have had to deal with it since at least the 1960's. The requirement was a earth rod for the greenhouse earth.

Take a walk round one of the metal sheds on a retail park and you will find earth rods fitted. Companies do not spend money unnecessarily and would not bother if there was not a problem.

Perhaps it's worth having some sort of open PEN fault detector or an earth rod fitted when dealing with charging EV's outdoors.

 

The pen fault problem has been around for decades. Most folks never came across it until ev's turned up leaving a big hunk of metal on the drive.
Those with a metal greenhouse and a power socket in it have had to deal with it since at least the 1960's. The requirement was a earth rod for the greenhouse earth.

Take a walk round one of the metal sheds on a retail park and you will find earth rods fitted. Companies do not spend money unnecessarily and would not bother if there was not a problem.

Perhaps it's worth having some sort of open PEN fault detector or an earth rod fitted when dealing with charging EV's outdoors.

As you rightly say, there's been a requirement to mitigate the risk from an open PEN fault for outdoor metal framed building for decades, they've always had TT earthing to mitigate the risk of a PME/TN-C-S supply neutral fault.

The main reason for integrating open PEN fault protection into EV charge points is because there are a fair few homes where it's either impossible, or perhaps just impractical, to fit an earth electrode. Main problem is high density housing where it can be very difficult to get a location for an earth electrode that's far enough away from other underground conductive stuff to be outside it's zone of influence.

The newer risk with EV charging is that of there being a DC earth leakage component. DC earth leakage tends to blind the common types of RCD used in domestic homes. This means that the RCD protecting other stuff in the house from having an electric shock risk, typically in the event of something like an insulation fault, may either operate too slowly or perhaps not at all. The risk is in a scenario such as a granny lead plugged in to a socket on a ring final, working just fine, but with a bit of DC leakage. Someone then plugs in a kettle with an insulation fault and gets a belt, because the RCD protecting that ring final didn't trip, because it was blinded by the DC leakage from the charger.

 

If the primary reason for wanting a granny charger is due to supply limitations, then the better route IMO would be a proper charger set with a lower output. Many are easily configurable.

I have two chargers, a 32A rolec and a 16A DIY unit built from a Viridian EPC. While i was waiting on a fuse upgrade from the DNO, i had the Viridian unit set to 8A. Its just an all round nicer job than dealing with a granny charger.

That way your meeting all the current safety standards, while dealing with the maximum demand issue. And if you shop about, its not massively more expensive, cars dont come with granny cables any more, so your going to have to buy something anyway.

Your starting point would be to find out how much current your garage supply can safely carry, and thus how much can realistically be dedicated to the car.

 

3kW is slightly in excess of the plug and socket rating (3,000 / 230 = 13.04A). Most granny leads approved for UK use can only charge at about 2.3kW (10A). Presumably you're using something not UK approved?

Granny charger was bought from a UK supplier. Specifications quoted = BS EN IEC 62752:2016+A1:2020 - In-cable control and protection device for mode 2 charging of electric road vehicles (IC-CPD) & BS EN IEC 61851-21-2021 - Electric vehicle conductive charging system Electric vehicle requirements for conductive connection to an AC/DC supply

Yes, 3kW is possibly pushing the envelope a bit (Actually looking at the Octopus information it is just under 2.8kW ), but the CU upgrade was to accommodate a wall-box in the future, so the only point of failure COULD be the wall socket, which is EV rated anyway so should last a few years.

There was no mention of PEN protection anywhere in the literature/specification, just over & under voltage protection, which I assumed was the same - Probably not?

Of course, there are exceptions.
Out of interest did you go for a Matt:e box or similar or did you have an earth rod ?

Matt:e ?
No there is no earthing rod, but according to the specification it has ground protection, and the garage master switch is connected directly to the house supply (Via Tails), therefore using the house earth. Apparently an earth rod is no longer required as stated in IET wiring regulations update in 2020.

Eventually, when I get a BEV, I will complete the installation and get a wall box. But until then my portable charger works for me and my PHEV.

 

There was no mention of PEN protection anywhere in the literature/specification, just over & under voltage protection, which I assumed was the same - Probably not?

Overvoltage and undervoltage can be symptoms of a PEN fault and detection of them is accepted by the regulations, so your system may be compliant with the letter of the law, but it's not a very satisfactory system, prone to both false positives and false negatives.
Where PEN voltage can be measured against a reliable real earth (rod in the ground) it's much more robust.

 

Granny charger was bought from a UK supplier. Specifications quoted = BS EN IEC 62752:2016+A1:2020 - In-cable control and protection device for mode 2 charging of electric road vehicles (IC-CPD) & BS EN IEC 61851-21-2021 - Electric vehicle conductive charging system Electric vehicle requirements for conductive connection to an AC/DC supply

Yes, 3kW is possibly pushing the envelope a bit (Actually looking at the Octopus information it is just under 2.8kW ), but the CU upgrade was to accommodate a wall-box in the future, so the only point of failure COULD be the wall socket, which is EV rated anyway so should last a few years.

The maximum continuous safe current that a UK socket outlet can supply is 10A, which is about 2.3kW (may be a bit more if your supply voltage is on the high side). All UK approved granny leads are limited to 10A because of this. Sadly there are loads of fakes on the market, sold on outlets like Amazon and Ebay that carry fake safety approvals and often overload the plug and socket by allowing charging at more than the 10A safe limit. Very often these will have UK CA or CE marks along with other fake approval markings.

There was no mention of PEN protection anywhere in the literature/specification, just over & under voltage protection, which I assumed was the same - Probably not?

The installer of the EV marked outlet had, by law, to adhere to the wiring regs, BS7671:2018. Section 722 is the specific part of those regs covering outlets for EV charging. That section stipulates that any outlet installed for the purpose of EV charging must have Type B, Type EV or Type F RCD protection and must also have protection from an open PEN fault.

 

There are EV specific charging sockets which are rated for 13A continuous operation, may be worth getting one of those installed. Still should only be limited to 10A, but likely to have a longer service life. Provided the socket is in good condition a granny charger should be fine. There are PEN fault risks but there are mitigations for those available ... and arguably the risk is incredibly low anyway.

 

The problem with the open PEN fault is that although it is rare, there are only a few hundred of these faults on the distribution networks each year, the consequences arising from this fault can be both lethal and without any warning to any passer by that happens to touch the car.

It's one of those faults where something really has to be done to mitigate the risk, just because it could kill someone that just innocently brushes against a plugged in car, whether actually charging or not (because the high voltage from this fault will be on the protective earth).

If someone only charges their car (without open PEN fault protection) in their own secure garage, so it's only themselves at risk, then it's up to them whether to consider protecting against this. The issue for me is the risk to the unwary passer by.

 

Wow, I wasn't expecting to open a can of worms but some interesting comments.

Spoke to Volvo dealer today, new cars come with an installed Ohme charger, so I'm proposing this be installed on the house and my mother uses this to charge the car maybe every week or so.
Charging schedule will be set by the car.
Phone signal is poor where she lives, not sure if this will be a problem??

 

The Ohme uses a multiple network SIM so a poor signal with a couple of providers might leave you thinking it wont work but it may well be OK using another network.

There are also boosters available to fit to the property which might be useful for more than just the chargepoint connectivity.

Best of luck.

Gaz

 

Use Octopus GO and the cars timers, the few pence saved over a week with this low usage are not worth the hassle of apps and setting up the ohme for use with IOG IMO.
On Go it will be simply plug in and leave to the car to start and finish the charge

 

Agreed, Octopus Go and use the car schedule.
Can the Ohm be set to be on 24/7 and not need a SIM and what happens after 3yrs with the SIM is it then chargeable?

 

There is no 3 year limit.

Gaz

 

The Ohme needs setting up with an App in the first place I gather but once done that should be it. I have a Zappi which can be programmed via the front panel buttons and has no need of any internet connectivity (SIMS/Ethernet/wifi) unless you want it.

 

Have you thought of these Voldt® Type 2 - 16A blue commando socket | 1 phase | Adjustable 8A - 16a | 3.7kW | EV charging cable – VOLDT
Gets over the power problem and a decent sparky will sort the rest out.

 

Have you thought of these Voldt® Type 2 - 16A blue commando socket | 1 phase | Adjustable 8A - 16a | 3.7kW | EV charging cable – VOLDT
Gets over the power problem and a decent sparky will sort the rest out.

The snag with that is that the installation cost may well end up higher than for a charge point, as the interlocked commando outlet, plus Type B RCD (or a Type EV or Type F), plus open PEN fault protection will add another ~£300 to £350 on to the cost, plus the additional labour to fit and test it.

 

Yes, but will take a long time if charging from a low state of charge. But if only topping up it should be fine. If you want a higher wattage facility (6-7kw) you’ll need a 32a circuit installing with the necessary space in your consumer unit and a wall box (for you to connect into) and other gubbins which may be financially prohibitive.