Electric Vehicle (EV) charging and thunderstorms - Is it safe/recommended?

Thanks for this @PeterR1947 ….

So presumably the suggested installation of an earth rod is instead of using the earth provided by the PME isn’t it?

Hi @Transparent I’m not really sure, when I have nothing better to do, I’ll take of the front of my zappi and have a look!

Thanks @PeterR1947 

To help others understand what we’re discussing, here’s the diagram which I pictured in my head when I suggested above that an EV charger could have two separate earths.

So I’ve conjectured that the case/electronics has an earth stake, and that there are internal lightning/surge suppressors to quench whatever nasties arrive via the live & neutral. These too need a path to earth.

I’m not saying this is how it should be. I’m merely putting the hypothesis forward for discussion.

So, my install doesn't have sn earth rod, it has a "Matt:e" device inline, but my understanding from installers is it does a similar job. This was done due to the fact the cable can in theory reach a public lamp post and (I quote the engineers here) "Some idiot could put the connector to the lamp post" so I believe it essentially is the same as the rod and i guess for similar sudden changes in potential and the reason i know my voltage was often over 253V (after kaluza confirmed this issue) and hence my substation had to be adjusted is the device kept triggering normally! 

Also, just checked this morning at the relatively new polar charger in devon and no comments about thunderstorms on that one. I think it may be just to indeed protect the v2g more (or just being overcautious, like the do not immerse laptop in water type warnings.)

The Matt:E device is a different strategy. It has (relatively slow) over/under voltage detection. When such an event occurs, it disconnects the EV charger from the supply, including the earth.

I agree that this satisfies the requirements for connection in a property that has a PME supply (earth provided via the Neutral, which is connected to ground at the sub-station).

Using the O-PEN device, the isolation breaker must operate within 5secs. By that time, any self-respecting lightning strike will have long since done its damage and departed.

That’s why I’ve drawn a pair of Varistors in the above diagram. These should be conducting within a microsecond, thus offering a path to earth by the time the peak lightning pulses arrive.

Hi,

I've had the unfortunate event of a large power surge causing damage to both my car and charging unit. I'm trying to recoup the costs incurred onto insurance and also get this issue raised with others as I believe the majority of EV owners are completely unaware that this could happen.

If anyone has any avenues to suggest they would be most welcome.

Cheers

Oh no, sorry to hear this, @Mateus77 - can you share any more info this?

@Jequinlan @sylm_2000 @PeterR1947 @NeilG @Andras @Mikeyoung and a very recent new EV owner @Transparent might have some advice, but I’d suggest we need a bit more info first. For example what model of EV and what charger do you have?

This is worth a read:

and this:

Hi,

The EV is an Audi A3 e-tron, so one of the earlier models launched.

The charger is a Rolec unit installed by one of their approved installers with an earth rod internal to the garage I have.

The damage was caused by a power surge locally rather than a direct strike to my property or the car.

The car was plugged in but not actively charging. At present the only avenue I have had to escalate these failings is to raise a case with TMO and see if they determine that the warnings and systems in place are deemed inadequate to protect consumers.

Thanks

Hi @Mateus77 and sorry to hear of your plight.

I have lots of information I can share with you, but I’ll try not to swamp you.

The damage being caused by a surge in the locality makes perfect sense to me. If you had a direct lightning strike it effectively raises the voltage of everything in your house to n-thousand volts, and then it falls again. There’s no actual potential difference across any device.

But a nearby strike can cause more serious damage. The copper conductors carrying power and telephone into your home will propagate the surge-front at two-thirds the speed of light. But the ‘ground wave’ will be delayed by the resistance of the soil and rock.

Thus any device which is earthed will see thousands of volts across it.

I too had a couple of nearby lightning strikes yesterday. I’m on top of a hill near the southwest corner of Dartmoor!

The trip connecting mains power to my well pump was ‘taken out’ but everything else continued as normal. There are three reasons for this:

• I have a pair quality surge protection devices on the mains incomer to the house
• I have a properly installed (and tested) earth system, appropriate for the type of mains supply from my substation transformer
• My new EV (VW ID3) does not yet have a wall-mounted ‘charger’. I use a 32A socket, described here in a separate topic.

The reason the well-pump always trips is because it has its own second path to earth via the column of water in the pipe!

Have a look through that other topic first, and keep going until you reach the post where you’ll find this diagram

Secondly, please complete your Forum Profile page. That’s where we look to get an idea of whereabouts you are in the country.

Lightning and earthing characteristics change across the regions, so these bits of background information are useful.

Thirdly, post back here with more specific detail of your situation:

• does your house have an earth-stake?
• is the feed from your substation underground or overhead? What distance?
• a photo of your Service Fuse and electricity meter would be useful
• detail of what damage you believe has happened to the car and the charger, with photos if relevant
• check any wired computer network you may have. Lightning has a tendency to make networked interfaces go intermittent. They sort of work, but slower.

I’ll stand by to respond again once I know more.