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Wiring EVSE on 230V Three-Phase Without Neutral

Discussion in 'Europe' started by MrBravo, Sep 29, 2016.

  1. MrBravo

    MrBravo Member

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    Location:
    Belgium
    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).

    3p without.PNG

    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?
     
  2. MrBravo

    MrBravo Member

    Joined:
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    Belgium
    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?
    - Will the car on-board charger mange correctly if the electricity is supplied like this?
    - Is this wiring Model S/X specific? Would another vehicle be damaged or it simply would not charge?
    They also mention that one should...
    I hope this information is useful to someone else as well.
     
  3. arg

    arg Member

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    Cambridge, UK
    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.
     
  4. miimura

    miimura Active Member

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

    [​IMG]
    Image from Wikipedia
     
  5. arg

    arg Member

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    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.
     
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  6. arg

    arg Member

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    That should have said "wired in Y configuration".
     
  7. emir-t

    emir-t Member

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    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!
     
  8. arg

    arg Member

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    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.
     
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