Wiring EVSE on 230V Three-Phase Without Neutral

[MrBravo]

I have just moved in a new house in Belgium, where I have a 3-phase electricity without neutral (L1, L2, L3, PE). In my previous house I had only 1-phase (L1, L2, PE) electricity. In both cases the voltage between any two phases is 230V, but between a phase and ground is less.

I know that there is a great thread about Belgian neuterprobleem here, but that does not answer my question.

The question: I saw that in Tesla Wall Connector manual there is a graph showing to connect to the phases L1-L1, L2-L2, L3-N, PE-PE (as on the left side of the picture). Then, if I understand correctly, I end up with the following connections through the relay (right side of the image).

Is this the way to wire a three-phase EVSE without neutral? How do I properly wire an EVSE (a non-Tesla Wall Connector) in this situation for three-phases? Can someone confirm that this will work for only for Tesla vehicles? Would other vehicles be damaged or simply not charge?

 

[MrBravo]

Since nobody replied, I sent this question to Tesla service e-mail address. They kindly answered to my questions:

- Do I understand correctly that the Tesla Wall Connector is wired to the plug as I have drawn below?

Basically, yes. However there is more to it than just the phase and grid wires. Communication (CP and PP) also needs to be functional.

- Will the car on-board charger mange correctly if the electricity is supplied like this?

Yes, the onboard charger is able to handle this type of supply

- Is this wiring Model S/X specific? Would another vehicle be damaged or it simply would not charge?

The few electric vehicles that can charge 3-phase, can only do so with a Neutral. By my knowledge, only the Model S and X are capable of charging on 230V 3-phase. The Wall Connector has been designed in such a way that it doesn’t damage other vehicles when connected to a 230V 3-phase grid. Most vehicles simply won’t charge when connected.

They also mention that one should...

Be aware that not all charging stations are capable of handling 230 3-phase grids the way the Wall Connector can.

I hope this information is useful to someone else as well.

 

[arg]

Note that this wiring is only for places with 230V phase-to-phase voltage - not for the more common 400/230V three phase (which can also confusingly be called 230V since that's the L-N voltage).

It is reasonably common to find the 4-pin red sockets used on 400/230V systems for equipment where neutral isn't required, but unfortunately there's no way to use those for Tesla charging (the wiring you are using would give too high a voltage in that case).

I can't see any good reason why your setup would cause damage to non-Tesla vehicles, though it's not unheard of: the Tesla UMC used in single-phase mode (which runs L1 to all three phase pins to suit early single-charger Model S) will damage a Renault Zoe.

 

[miimura]

This scheme is due to the power supply using the Delta configuration instead of Y, correct?

Image from Wikipedia

 

[arg]

This scheme is due to the power supply using the Delta configuration instead of Y, correct?

Sort-of. It's very common to use a Y transformer at the source end (with the centre 'neutral' point either earthed or used for isolation monitoring), but if the neutral isn't distributed you can only connect loads to it in Delta (even though the source is Y).

Note that Model S (in markets with the type2 connector) has in effect three separate chargers, wired in delta configuration to 4 pins on the connector; each can take up to 277V (since one of the cases they are designed for is USA-standard 480/277V three-phase as used to supply Superchargers)

In Europe, the most common configuration is 400/230V three phase with the neutral earthed and also distributed to consumers, with small loads using only one of the phases plus neutral. In the UK, houses often get only one phase with alternate houses down the street getting the other phases, while other parts of Europe more commonly supply all three phases and neutral to each house at a lower current. The 400/230 voltage (400V between phases, 230V phase-to-neutral) is approximate - some areas such as France were historically 220V +-6% with others such as the UK on 240V+-6%, but we all now call it 230V+-10%. Plugs and sockets for high power equipment are available in two formats - 5 pin (3 phases, neutral and earth) or 4-pin (3 phases, earth but no neutral).

The Model S charges happily on this voltage with the chargers connected in delta configuration, but it must have the neutral - the phase-to-phase voltage is too high to use directly with the Model S chargers. Model S can also use just one phase if that is all that's available - feeding just one of the three chargers, or wiring them in parallel if full power is needed. Early cars delivered in Europe needed this parallel wiring to be provided externally, but this is a Tesla-specific thing and not provided on public chargepoints (it is provided by the UMC with the blue adapter fitted). More recent cars have internal switching to allow them to be used at full power on public chargepoints in countries where high power single-phase is common (such as the UK). Unfortunately, if you find a 4-pin socket (no neutral) there's nothing you can do to charge from it.

The other configuration found in a few places (most well known in Norway, but the OP has it in Belgium) has 230/132V three-phase with no neutral provided to customers. Small appliances requiring 230V can still be used with the same plugs as elsewhere, just that the two pins are now two of the three phases rather than one phase and neutral. The Model S could charge from this in single-phase mode, but the power available in a typical house with this sort of supply would not permit large currents to be drawn from a single phase so charging would be slow. The special wiring mentioned by the OP above takes advantage of the fact that the Model S has effectively three separate chargers, and provides phase-to-phase voltage to two of them, leaving the third unused. Hence this slightly non-standard arrangement allows the Model S to charge twice as fast as it would be able to in single phase mode, but not quite as fast as if it were able to use all three phases (which it can't because there's no neutral on the supply and the Model S end is hard-wired in the Y configuration.

The other issue with these supplies is earthing: the Telsa UMC normally checks that it has a good earth connection by comparing the earth to neutral - on the 'standard' 400/230V system, the neutral is earthed and so it expects to find earrh and neutral close together with L1 230V away from it. In the Norwegian case at least, their 230V three-phase is unearthed, so the standard UMC will not work (even to charge from a standard domestic socket): there's a Norway-specific version of the UMC to avoid this problem. I'm not sure of the situation in Belgium, but it's very likely the same. Apparently the new Wall Connector doesn't have this earth check in it, so the non-standard wiring can be used.

 

[arg]

Note that Model S (in markets with the type2 connector) has in effect three separate chargers, wired in delta configuration to 4 pins on the connector; each can take up to 277V (since one of the cases they are designed for is USA-standard 480/277V three-phase as used to supply Superchargers)

That should have said "wired in Y configuration".

 

[emir-t]

Sort-of. It's very common to use a Y transformer at the source end (with the centre 'neutral' point either earthed or used for isolation monitoring), but if the neutral isn't distributed you can only connect loads to it in Delta (even though the source is Y).

Note that Model S (in markets with the type2 connector) has in effect three separate chargers, wired in delta configuration to 4 pins on the connector; each can take up to 277V (since one of the cases they are designed for is USA-standard 480/277V three-phase as used to supply Superchargers)

In Europe, the most common configuration is 400/230V three phase with the neutral earthed and also distributed to consumers, with small loads using only one of the phases plus neutral. In the UK, houses often get only one phase with alternate houses down the street getting the other phases, while other parts of Europe more commonly supply all three phases and neutral to each house at a lower current. The 400/230 voltage (400V between phases, 230V phase-to-neutral) is approximate - some areas such as France were historically 220V +-6% with others such as the UK on 240V+-6%, but we all now call it 230V+-10%. Plugs and sockets for high power equipment are available in two formats - 5 pin (3 phases, neutral and earth) or 4-pin (3 phases, earth but no neutral).

The Model S charges happily on this voltage with the chargers connected in delta configuration, but it must have the neutral - the phase-to-phase voltage is too high to use directly with the Model S chargers. Model S can also use just one phase if that is all that's available - feeding just one of the three chargers, or wiring them in parallel if full power is needed. Early cars delivered in Europe needed this parallel wiring to be provided externally, but this is a Tesla-specific thing and not provided on public chargepoints (it is provided by the UMC with the blue adapter fitted). More recent cars have internal switching to allow them to be used at full power on public chargepoints in countries where high power single-phase is common (such as the UK). Unfortunately, if you find a 4-pin socket (no neutral) there's nothing you can do to charge from it.

The other configuration found in a few places (most well known in Norway, but the OP has it in Belgium) has 230/132V three-phase with no neutral provided to customers. Small appliances requiring 230V can still be used with the same plugs as elsewhere, just that the two pins are now two of the three phases rather than one phase and neutral. The Model S could charge from this in single-phase mode, but the power available in a typical house with this sort of supply would not permit large currents to be drawn from a single phase so charging would be slow. The special wiring mentioned by the OP above takes advantage of the fact that the Model S has effectively three separate chargers, and provides phase-to-phase voltage to two of them, leaving the third unused. Hence this slightly non-standard arrangement allows the Model S to charge twice as fast as it would be able to in single phase mode, but not quite as fast as if it were able to use all three phases (which it can't because there's no neutral on the supply and the Model S end is hard-wired in the Y configuration.

The other issue with these supplies is earthing: the Telsa UMC normally checks that it has a good earth connection by comparing the earth to neutral - on the 'standard' 400/230V system, the neutral is earthed and so it expects to find earrh and neutral close together with L1 230V away from it. In the Norwegian case at least, their 230V three-phase is unearthed, so the standard UMC will not work (even to charge from a standard domestic socket): there's a Norway-specific version of the UMC to avoid this problem. I'm not sure of the situation in Belgium, but it's very likely the same. Apparently the new Wall Connector doesn't have this earth check in it, so the non-standard wiring can be used.

Wow this cleared A LOT of things up for me. You did mean the Model S chargers were in Y configuration but Delta is actually a typo though right?

Thanks!

 

[arg]

Wow this cleared A LOT of things up for me. You did mean the Model S chargers were in Y configuration but Delta is actually a typo though right?

Sorry about that - I tried to write a post to make things clear, then spoiled it all by stupid typos! Here's the post again with typos corrected. Note also that in british-english, we more commonly say "star" vs "delta", but it's exactly the same thing as "Y" or "Wye" vs "Delta" in USA-english.



Sort-of. It's very common to use a Y transformer at the source end (with the centre 'neutral' point either earthed or used for isolation monitoring), but if the neutral isn't distributed you can only connect loads to it in Delta (even though the source is Y).

Note that Model S (in markets with the type2 connector) has in effect three separate chargers, wired in Y configuration to 4 pins on the connector; each can take up to 277V (since one of the cases they are designed for is USA-standard 480/277V three-phase as used to supply Superchargers)

In Europe, the most common configuration is 400/230V three phase with the neutral earthed and also distributed to consumers, with small loads using only one of the phases plus neutral. In the UK, houses often get only one phase with alternate houses down the street getting the other phases, while other parts of Europe more commonly supply all three phases and neutral to each house at a lower current. The 400/230 voltage (400V between phases, 230V phase-to-neutral) is approximate - some areas such as France were historically 220V +-6% with others such as the UK on 240V+-6%, but we all now call it 230V+-10%. Plugs and sockets for high power equipment are available in two formats - 5 pin (3 phases, neutral and earth) or 4-pin (3 phases, earth but no neutral).

The Model S charges happily on this voltage with the chargers connected in Y configuration, but it must have the neutral - the phase-to-phase voltage is too high to use directly with the Model S chargers. Model S can also use just one phase if that is all that's available - feeding just one of the three chargers, or wiring them in parallel if full power is needed. Early cars delivered in Europe needed this parallel wiring to be provided externally, but this is a Tesla-specific thing and not provided on public chargepoints (it is provided by the UMC with the blue adapter fitted). More recent cars have internal switching to allow them to be used at full power on public chargepoints in countries where high power single-phase is common (such as the UK). Unfortunately, if you find a 4-pin socket (no neutral) there's nothing you can do to charge from it.

The other configuration found in a few places (most well known in Norway, but the OP has it in Belgium) has 230/132V three-phase with no neutral provided to customers. Small appliances requiring 230V can still be used with the same plugs as elsewhere, just that the two pins are now two of the three phases rather than one phase and neutral. The Model S could charge from this in single-phase mode, but the power available in a typical house with this sort of supply would not permit large currents to be drawn from a single phase so charging would be slow. The special wiring mentioned by the OP above takes advantage of the fact that the Model S has effectively three separate chargers, and provides phase-to-phase voltage to two of them, leaving the third unused. Hence this slightly non-standard arrangement allows the Model S to charge twice as fast as it would be able to in single phase mode, but not quite as fast as if it were able to use all three phases (which it can't because there's no neutral on the supply and the Model S end is hard-wired in the Y configuration).

The other issue with these supplies is earthing: the Telsa UMC normally checks that it has a good earth connection by comparing the earth to neutral - on the 'standard' 400/230V system, the neutral is earthed and so it expects to find earth and neutral close together with L1 230V away from it. In the Norwegian case at least, their 230V three-phase is unearthed, so the standard UMC will not work (even to charge from a standard domestic socket): there's a Norway-specific version of the UMC to avoid this problem. I'm not sure of the situation in Belgium, but it's very likely the same. Apparently the new Wall Connector doesn't have this earth check in it, so the non-standard wiring can be used.

 

[MrBravo]

UPDATE: I have wired the charger as described. The result on a single-charger (16A) Model S 85 is as expected. I can charge with speed 32-33 km/h. It shows 27/28 A.

 

[Superduperrrr]

Mr Bravo, same issue by me (3 phase but no neutral) ...so basically what did you do? Y Configuration ? Do you need a special equipment or just to connect as described in the scheme, bridge L1, L2,L3 to neutral?

 

[MrBravo]

Mr Bravo, same issue by me (3 phase but no neutral) ...so basically what did you do? Y Configuration ? Do you need a special equipment or just to connect as described in the scheme, bridge L1, L2,L3 to neutral?

I did not need any special equipment. When connecting the charger to the power supply I did like in the drawing in my original post:
- supply L1 - charger L1,
- supply L2 - charger L2,
- nothing - charger L3,
- supply L3 - charger N,
- supply PE - supply PE.

 

[vincentlevet]

Hi Mr Bravo, I hope you will see my message.
I am setting up the same thing as you (in Belgium, with 230v Delta no neutral grid too).
I don't have the car yet, but I'm preparing.
Can you please share what you Tesla charger app is showing. I'm wondering if everything is set correctly as it looks like the L2 is not detected in my case.

 

[MrBravo]

Hi Mr Bravo, I hope you will see my message.
I am setting up the same thing as you (in Belgium, with 230v Delta no neutral grid too).
I don't have the car yet, but I'm preparing.
Can you please share what you Tesla charger app is showing. I'm wondering if everything is set correctly as it looks like the L2 is not detected in my case.

Hi Vincentlevet,
Unfortunately I can not share the image from my tesla charger app, because I am not using a Tesla wallbox. Currently I have a wallbox that I made myself, but basically with the above schematic. Sorry.
The Tesla car app on my phone shows what the display in the car does (as posted above), but that is not what you are asking for.
I can suggest to take a multimeter and check twice every connection to make sure they are correct and pass through correctly to where you want each phase to go on the plug. The contactor in the charger will be off while you test, of course.

 

[dollob]

I have my Gen 2 Tesla Wall connector working on 230V three-phase delta (without neutral), confirmed working both for Model Y and Model X (2017, 16.5kW on-board charger). I needed to update the firmware on my Gen 2 Wall connector to get the full 11kW on my Model Y - a bit of a faff - see here TWC Gen II firmware update. I haven't tested it, but I would imagine the new Gen 3 wall connector would work the same, I am not sure about 3rd party chargers, but MrBravo here above seems to have had success, bravo! I have also sucessfully used it to charge non-tesla EVs, I suppose they are only concerned whether there is 230V between L1 and N.

Newer Teslas (including M3/Y and new MS/X), have full 11kW support for 3-ph delta. Older teslas only support around 7.4-8.5kW depending on whether it's equipped with dual/single/17kW. I applaud Tesla for being the only EV supporting this configuration for us living with 230V three-phase delta!

Below is a picture of a Model Y charging - in my area the voltage is a bit low at 220V so we're only charging at ~10kW. It draws 28A equally balanced on each phase, beautiful. Of course you can dial it down either on the charger or in the car. There is also a picture of the service screen, with it correctly identifying the supply as 'Three Phase Delta'.

 

[dollob]

As for a bit more of an in depth explanation on Tesla's 230V delta-three phase charging, adding to arg's post above:
For Tesla Model S/X models pre 2021, they either have a single (16A, 11kW), dual (32A, 22kW) or mid (24A, 17kW on-board chargers. I call the last one mid because it's about in the middle of other two. I think the single/dual charger choice was discontinued in around 2017, and all Model S/X from 2017-2021 have mid 17kW chargers.
For Tesla Model 3/Y, as well as new Model S/X (2022-) all have the same 11kW (16A) chargers. These support full-power (11kW) on 230V three-phase delta without neutral, using contactors to switch to a delta configuration - I will explain below.

All Tesla on-board chargers are wired in a three-phase Y configuration, with three charging modules - one connected on each phase. By default, the three charging modules are all connected on one end to the neutral. In a 400V charging scenario, there will be no current flowing in the neutral and each of the three modules draws 16A between phase and neutral, giving 11kW power (24A in mid charger cars and 32A in dual charger cars). In the diagram, the green rectangles represent the modules.

Newer chargers have a contactors which are able to connect the three individual modules into a delta configuration. Each of the modules still draws 16A*230V between phases, giving 11kW total power, but by virtue of the delta configuration, the current on each line L1,2,3 is 16*√3 = 27.7A. The current on each phase is balanced, the most ideal scenario.

Older Teslas do not have the function to switch to delta configuration and are thereby limited by the Y shape of the on-board charger. They can only connect two of the charging modules. As they are limited by the 32A limit per phase (maximum permitted on the wiring), therefore the other two phase currents can be at 32/√3 = 18.5A. The two charging modules are therefore run at 18.5A each, giving a total power of 2*18.5*230 = 8.5kW. (N.b. this is for dual or mid chargers, for single chargers, the current per module is limited to 16A, therefore giving 7.4kW.)
This means the load will be unbalanced across the phases, L1=18.5A, L2=18.5A, L3=32A. Not ideal, but still more balanced than if they were on single-phase, L1=32A, L2=32A, L3=0A. This configuration also allows slightly more power than the single-phase setup, if you have the mid or dual chargers installed (8.5kW vs 7.4kW).

What this means in practice is that for the same power (lets say 5kW) instead of pulling 22A on two phases (unbalanced), you only have to pull 12.5A balanced acrosss all phases. Meaning for a home that may only have a 20A main fuse, can use the charger properly - the magic of three phase power! I'm honestly very dissapointed other car manufacturers haven't implemented a 230V three-phase delta support.

P.s. the Tesla Wall connector connected in 3-phase delta does work for non-Teslas which only accept single phase power (as they aren't bothered by L3). As for vehicles that support 3-phase, I'm not sure. Note that I am on a TT grounding system.

 

[dollob]

Newer chargers have a contactors which are able to connect the three individual modules into a delta configuration. Each of the modules still draws 16A*230V between phases, giving 11kW total power, but by virtue of the delta configuration, the current on each line L1,2,3 is 16*√3 = 27.7A. The current on each phase is balanced, the most ideal scenario.

Correction: The green numbers (current through each charger module) should be 16A, not 28A. The current on each line is correct though, 28A.