EV charge port.

[Sophon]

Sometime in the next couple of years we will probably replace our car with something more current. I would consider buying a plug-in hybrid, so if I am going to change my set-up to include a back-up generator, maybe it would be a good time to also prepare for somewhere to put the charging station.  

 

Out car port is not too far from where I will put the new box for the change-over switch, over current device etc., so it will be fairly simple to run new wiring from the box to the future charging station. Running supply to the charging station from our main CU would be much more complicated. I would think that 6 sq.mm. wiring would be enough, or is a heavier gauge required (I have read that chargers for electric cars typically are 16/32 Amp)?  I do have normal outlets in the water tank room next to the car port, but they are only supplied via 2.5 sq.mm. wiring and protected by a 20 Amp breaker, so insufficient for an electric vehicle fast charger.

 

I would have to split the incoming supply, so is there some kind of DIN rail "two-way splitter" device, that I could install in the new box in preparation for a possible future charging station? I will not do the rest of the wiring until I know for sure that my next car will be plug-in. Would such a device go before or after the change-over switch for the generator? I will not need to charge the car when running the generator (the generator probably couldn't handle it anyway).

[Crossy]

I've split this off from the original thread as it deserves it's own.

[Crossy]

A couple of these should make your split easy and safe all sorts of sizes

https://www.aliexpress.com/item/32961240438.html

 

 

I'd run the biggest service you can, 32A is about 7kW that may not be enough for future fast chargers. If you're doing new wiring I'd run at least 10mm².

 

 

 

[Sophon]

Thanks Crossy.

 

When you say "a couple of these" I assume you mean one for the live wire and one for neutral? Some of the devices looks a little confusing to me (more than one input), and others seem over the top for what I need (e.g. supporting up to 120 sq.mm. wires). Would the JUT11-80 be the most suitable one for me, since my incomer is 16 sq.mm and I would need 16 sq.mm (to the main CU) and 10 sq.mm (to the charging station) wires coming out?

 

So this splitter would go before the generator change-over switch, and I assume with it's own dedicated breaker between the splitter and the new charging station?

[Crossy]

Yeah, one for each L and N. Best bet is to sketch out what you intend doing and we can review and modify.

 

It is probably best to split the incoming unless you intend having a big genset.

 

I'd go for the 125, they're only a buck more expensive.

[Sophon]

It's not about the price, but I'm not sure I understand how the JUT11-125 is supposed to work:

Why is there two incoming ports, is it just so to support different wire thicknesses? And what does the outgoing "x6 ... x4" mean? I understand that it supports wires between 2.5 sq.mm. and 16 sq.mm., but I can see six tightening screws, so where does the "x4" come in.

 

Edit: I just noticed that the U.S. description is different, it doesn't include the "x4" part.

[sometimewoodworker]

A relevant video about EV vehicle earthing systems and the interesting ways (sometimes deadly ways) you can screw up by not knowing what you can and should do

 

 

[Crossy]

10 hours ago, sometimewoodworker said:

A relevant video about EV vehicle earthing systems and the interesting ways (sometimes deadly ways) you can screw up by not knowing what you can and should do

 

John Ward does some excellent videos definitely worth watching.

 

Thailand is TN-C-S with MEN (equivalent to UK PME) so your charge point should be TT earthed and bonded to any metalwork of the car port to keep everything at the same potential if something goes awry.

[Sophon]

I was thinking something like this:

 

I am fairly confident that I don't understand how the surge protection device works, so I have almost certainly got that part wrong. I have put the generator changeover switch first, because I currently don't have any means of isolating the mains, if I need to make changes to the parts of the CUs that are live, other than pulling the live wire at the meter. So I wanted to use the changeover switch for that, turning it to generator power (when the generator is not running), would turn everything off.

 

However, thinking about it, I should for safety reasons probably have a RCBO in the new box, and use that as a means of turning everything off instead.

[Crossy]

Looks pretty OK.

 

I would put an isolator/MCB between the transfer switch and the grid supply. So you can isolate everything for service.

 

Do NOT connect your charge port to the grid earth, bang in a local rod well away from any other rod. Connect that rod to any exposed metalwork in your car port too. Did you watch the above video?

 

Does your genset have an earth terminal? Connect it.

 

Be careful with any RCBO in front of a N-E (MEN) link.

 

[Sophon]

10 minutes ago, Crossy said:

Looks pretty OK.

 

I would put an isolator/MCB between the transfer switch and the grid supply. So you can isolate everything for service.

 

Do NOT connect your charge port to the grid earth, bang in a local rod well away from any other rod. Connect that rod to any exposed metalwork in your car port too. Did you watch the above video?

 

Does your genset have an earth terminal? Connect it.

 

Be careful with any RCBO in front of a N-E (MEN) link.

 

 

How far is "well away"? The car port is about ten meters away from our current earth rod, and it doesn't have any exposed metalwork.

 

I haven't bought a generator yet, so I don't know if it will have an earth terminal or not.

 

No, I didn't watch the video yet but will do. I will not do any of the wiring for the EV charging port until I know that I will be buying a plug-in hybrid. That will probably be at least a couple of years down the line. But if I am going to rewire for the generator, O/U voltage protection and surge protection, I want to prepare the connections in the box (and only that) for a potential charge station.

 

It's not that we really need a generator, we probably only have an average of one black-out per month (mostly in the rainy season), and they seldom lasts more than an hour. But life gets boring and uncomfortable very quickly when the power is out, so it's a luxury that we would be prepared to pay for (within reason).

[Sophon]

This is our carport:

 

The charging port would probably be somewhere on the wall to the right of where the car is parked. The water tank room on the left already have plugs, but only supports up to 20A. Maybe that would be enough anyway, the car would always be charged at night so quick charging is not a priority. We only drive an average of about 600km per month.

[sometimewoodworker]

1 hour ago, Sophon said:

How far is "well away"? The car port is about ten meters away from our current earth rod, and it doesn't have any exposed metalwork.

 

I haven't bought a generator yet, so I don't know if it will have an earth terminal or not.

 

No, I didn't watch the video yet but will do.

Your proposed wiring has the potential to have the car live at 230V so as a minimum can encourage some very interesting sensations all the way to you or others being the central feature in the local cremation ceremony.

 

I posted the video with the warning for a good reason, and that is to prevent such excitement. WATCH the video and some or all your questions will be answered in more detail than you can easily get from even the qualified people here. After watching it we will be happy to answer questions.

[Crossy]

10 hours ago, Sophon said:

How far is "well away"? The car port is about ten meters away from our current earth rod, and it doesn't have any exposed metalwork.

I haven't bought a generator yet, so I don't know if it will have an earth terminal or not.

 

Sorry I wasn't clearer, "well away" is usually accepted as 2 x rod length, so with the standard Thai 2.4m rod that's about 5m. Your genset will have an earth terminal, I was just surprised you didn't draw it which made me wonder why.

 

The safety of EV ports it a hot subject in the UK with plenty of discussions in the IET forums. The regulations are still in a certain amount of flux with issues around failed PEN conductors and RCDs (there's potential for large DC components in fault currents which can swamp the usual devices - similar issues exist in solar power systems). The John Ward video addresses the common pitfalls.

 

I doubt there are any Thai regulations on EV ports yet, I'll ask my power-supply man, if he doesn't know nobody will, but I doubt they would be much different to the Western regs.

[mogandave]

It surprises me that a plug-in electric car does not include on on-board charger such that you can just plug the car into a typical 220 receptacle. 
 

Would the size or weight of the charger be prohibitive? 
 

It could be that the UL/CE listing requirements could take too long or (less likely) cost too much.

[sometimewoodworker]

4 hours ago, mogandave said:

It surprises me that a plug-in electric car does not include on on-board charger such that you can just plug the car into a typical 220 receptacle. 
 

Would the size or weight of the charger be prohibitive? 
 

It could be that the UL/CE listing requirements could take too long or (less likely) cost too much.

If you watch the John Ward video that I posted you would quickly find out that though it is certainly technically possible to do that it has failure modes that have your car with a 220V potential so;

cheap? Yes

simple? Yes.

deadly? Yes

[Crossy]

6 hours ago, mogandave said:

It surprises me that a plug-in electric car does not include on on-board charger such that you can just plug the car into a typical 220 receptacle. 

 

Most (all?) plug-in vehicles come with a "slow" (2-3kW) charger that will plug into a regular 220V outlet, it looks like a giant laptop power supply.

 

At the power / voltage levels we are looking at trying to make a big metal box (the car) a Class-2 appliance (which would remove the potential for a hazardous potential on the vehicle) would seem to be prohibitive.

 

So we have Class-1 which needs to be earthed, the risk being there being a potential difference between supply "earth" and real "earth" (which you are stood on).

 

[mogandave]

22 hours ago, sometimewoodworker said:

If you watch the John Ward video that I posted you would quickly find out that though it is certainly technically possible to do that it has failure modes that have your car with a 220V potential so;

cheap? Yes

simple? Yes.

deadly? Yes

I did watch about 10 minutes of it, but I could not understand what he was saying. 
 

I’ve worked around industrial electric vehicles for 40-50 years and plug in charging has never seemed to be much of an issue. 
 

 

[mogandave]

21 hours ago, Crossy said:

 

Most (all?) plug-in vehicles come with a "slow" (2-3kW) charger that will plug into a regular 220V outlet, it looks like a giant laptop power supply.

 

At the power / voltage levels we are looking at trying to make a big metal box (the car) a Class-2 appliance (which would remove the potential for a hazardous potential on the vehicle) would seem to be prohibitive.

 

So we have Class-1 which needs to be earthed, the risk being there being a potential difference between supply "earth" and real "earth" (which you are stood on).

So as long as there is a good ground, there is no real danger? 
 

As I understand it, a charger/transformer creates it’s own neural, so assuming the unit is fused, and there is a decent ground/earth, why is whether or not the service has the neural and earth tied together significant? 
 

 

 

[sometimewoodworker]

56 minutes ago, mogandave said:

I did watch about 10 minutes of it, but I could not understand what he was saying. 

So you then need to accept that using the house earth or bonding the earth used for the EV has the potential to kill anyone touching the car. That is the short version.

 

50 minutes ago, mogandave said:

So as long as there is a good ground, there is no real danger? 

If it is the correct earth in the correct location and not bonded yes.

51 minutes ago, mogandave said:

why is whether or not the service has the neural and earth tied together significant? 

Because a fault can kill anyone touching the vehicle.

 

1 hour ago, mogandave said:

I’ve worked around industrial electric vehicles for 40-50 years and plug in charging has never seemed to be much of an issue. 

Industrial power supplies are installed by people who understand the dangers involved and have the training to avoid them.

[Crossy]

In a nutshell.

 

The failure of the neutral in the TN-C-S system (like Thailand uses) can cause the installation "earth" and anything connected to it (the car) to approach phase voltage.

 

If you are stood on the "real" earth and touch the car - you die.

 

This is a massive concern in the UK hence the loooong discussions about it on the IET forum and the constanly changing regulations as to how to connect it all up.

 

A "local" earth near the charge point which is not connected to installation "earth" ensures that you and the car will be at about the same potential at all times and you don't die. Often this is referred to as a "TT island", it's the best way to connect your hot-tub too.

 

[VocalNeal]

23 hours ago, Crossy said:

Most (all?) plug-in vehicles come with a "slow" (2-3kW) charger that will plug into a regular 220V outlet, it looks like a giant laptop power supply.

 

OP is buying a plug in hybrid. Unlikely he will need to fast charge anything.

[Crossy]

3 minutes ago, VocalNeal said:

OP is buying a plug in hybrid. Unlikely he will need to fast charge anything.

 

True, but the hazard from an open neutral in a TN-C-S system is still the same ????

 

[mogandave]

2 hours ago, Crossy said:

A "local" earth near the charge point which is not connected to installation "earth" ensures that you and the car will be at about the same potential at all times and you don't die. Often this is referred to as a "TT island", it's the best way to connect your hot-tub too.

 

the installation “earth” being the earth in the distribution panel? 
 

So installed correctly, one would use the line & neutral from the panel, and a dedicated ground rod? 
 

Assuming you had three phase (or were in the US) would it not also be safe to use L1 & L2 & a dedicated ground rod?

 

Or I guess a three-phase charger? 

[sometimewoodworker]

2 hours ago, Crossy said:

A "local" earth near the charge point which is not connected to installation "earth" ensures that you and the car will be at about the same potential at all times and you don't die. Often this is referred to as a "TT island", it's the best way to connect your hot-tub too.

The one point missing from that is that the TT island earth needs to be good enough and far enough away from the house earth, this could (and for the U.K. now must) include the house itself, because a broken PEN is quite capable of inducing a potential via the island earth system if it and the house earth are too close together so your car could become live via the earth. Now isn’t that a fun thought? 

 

The earth bonding in the U.K. is going to require bonding to house steel and in Thailand the house could be bonded, mine is.

[Crossy]

Our TT island car port is a good 6m from the house, steel framed with two 2m rods on opposite corners (solar is on the car port). So no issues when we get an EV (Madam has decreed thye next car will be EV).

 

If things were really close I may be tempted to TT the whole lot (with a bunch of RCD/RCBOs of course).

[sometimewoodworker]

There is another point. Nothing connected to the house earthing system can be near enough to the car so that you can touch them both at the same time, because again you die if either is at line voltage. This will include extension cables, and anything connected to them, like a vacuum.

[Sophon]

My apologies for abandoning my topic for a while, but we had to arrange for one of our dogs to be put to sleep. Since then I haven't really been in the mood to work on this project.

 

I watched the video posted, and as a layman didn't really find it all that helpful. I get the point that an error/break in the supply cables could leave you with a charged neutral, and since neutral/earth is bonded in the main CU, consequently also with a charged earth connection. Therefore, I would need a separate earth that is not connected to the neutral. And to avoid transference from the potentially charged existing ground rod, the new ground rod has to be at least 5 meters away from the existing rod. What I don't get, is why the new rod also has to be away from the incoming power cables, since they are fully insulated (I am ignoring all the stuff about gas and water pipes, as not relevant to Thailand). The only way I can see any potential danger from the new rod being close to the power cables, is if my own buried cables are severed close to the rod. Wouldn't I be alerted to this by my power disappearing or the main RCBO tripping? And I don't really see how the cables could be severed short of something I did myself and would be fully aware of.

 

In response to earlier comments I have amended my diagram to include a main breaker, added earth to the generator (I have used my existing earth rod for this) and connected the charging station to a separate (new) earth rod.

 

All the connections for the EV charging port will not be done until/if I actually one day buy a plug-in hybrid vehicle, so I have indicated them as such in the diagram. Any comments to the new set-up?

 

I do have one new question. What kind of cable size is needed for the ground connection for the surge protection device and for the potential future EV charging port? My existing ground rod is connected with a 16 sq.mm. copper cable, but if the new connections can manage safely on less, then all the better.

 

Thank you again to all for your information.