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MIC and 3-phase supply

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  • 08-09-2020 10:10am
    #1
    st332
    Registered Users Posts: 147 ✭✭


    Hi,

    I've got a 3-phase supply in a recently-built home (it has a 3-phase heat pump).
    I asked the builder what the MIC was and he checked and said 16kVA.
    Is this 16kVA per phase or 16kVA overall? - I'm not sure what's typical.

    I know each phase has a 63A main fuse in the distribution box.


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    #2
    Zarco
    Closed Accounts Posts: 112 ✭✭Zarco


    st332 wrote: »
    Hi,

    I've got a 3-phase supply in a recently-built home (it has a 3-phase heat pump).
    I asked the builder what the MIC was and he checked and said 16kVA.
    Is this 16kVA per phase or 16kVA overall? - I'm not sure what's typical.

    I know each phase has a 63A main fuse in the distribution box.

    Sounds more like 12kva per phase


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    #3
    Zarco
    Closed Accounts Posts: 112 ✭✭Zarco


    I think it's what they (ESBN)probably call 29KVA on the application


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    #4
    st332
    Registered Users Posts: 147 ✭✭st332


    I assume the builder got it wrong so.

    I just had a look at the meter box outside, there are 100A fuses on each phase (photo attached)

    I'm looking into getting a charge point and have just put a deposit down on an electric car.
    The car can only charge at 11kW AC, but I figured I may as well get a 22kW charge point if possible for future proofing (most 3-phase points seem to be able to do 22kW as standard), so just want to make sure my connection is up to the job.
    In any case, I'll be getting on to the sparks the builder used to get a quote for the charge point, so he should be able to tell me what's what.


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    #5
    Zarco
    Closed Accounts Posts: 112 ✭✭Zarco


    Looks like 3P 63amp alright

    If you go to wire a 3P car charger from the meter cabinet you're going to need a consumer Main Protective device in the cabinet

    Isn't that the plan with these charging units that they're going to be wired from the meter cabinet?


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    #6
    st332
    Registered Users Posts: 147 ✭✭st332


    There is already a cable in place in the front garden for a charge point, wired back to the distribution board.
    Attached is the spec of the connection - it's on a 40A ELCB and 32A fuses.


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    #7
    Zarco
    Closed Accounts Posts: 112 ✭✭Zarco


    st332 wrote: »
    There is already a cable in place in the front garden for a charge point, wired back to the distribution board.
    Attached is the spec of the connection - it's on a 40A ELCB and 32A fuses.

    That's a SP chargepoint

    The 22 and 11 then would be 3P chargepoints


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    #8
    Zarco
    Closed Accounts Posts: 112 ✭✭Zarco


    Zarco wrote: »
    That's a SP chargepoint

    The 22 and 11 then would be 3P chargepoints



    Edit : I'm reading that wrong , it's probably 3P not T phase lol so that's 3P 32 amp chargepoint


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    #9
    st332
    Registered Users Posts: 147 ✭✭st332


    Zarco wrote: »
    Edit : I'm reading that wrong , it's probably 3P not T phase lol so that's 3P 32 amp chargepoint

    Yeah, there's definitely a 3P connection in place for a charge point.
    Just taken a look at the board; the ELCB and MCB are both 3P devices.


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    #10
    st332
    Registered Users Posts: 147 ✭✭st332


    I just dug up a "details of connection" notice from ESB Networks we got in the handover documents - it seems the MIC is indeed 16 kVA.

    I think with a car charging at night at 11kW plus a heat pump running at about 2-4 kW, this should be fine. The charger I'm looking at installing would have 3x CT meters on the incoming supply, just after the ESB meter, so could occasionally dial down the car charging to stay under the MIC.

    I reckon it's not worth increasing the MIC at this stage, if it might cost a few grand (the only upgrade cost the ESB list is €1,164 for upgrading 12kVA 1P to 16kVA 1P so I assume it will be more than this).


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    #11
    Zarco
    Closed Accounts Posts: 112 ✭✭Zarco


    st332 wrote: »
    I just dug up a "details of connection" notice from ESB Networks we got in the handover documents - it seems the MIC is indeed 16 kVA.

    I think with a car charging at night at 11kW plus a heat pump running at about 2-4 kW, this should be fine. The charger I'm looking at installing would have 3x CT meters on the incoming supply, just after the ESB meter, so could occasionally dial down the car charging to stay under the MIC.

    I reckon it's not worth increasing the MIC at this stage, if it might cost a few grand (the only upgrade cost the ESB list is €1,164 for upgrading 12kVA 1P to 16kVA 1P so I assume it will be more than this).

    16kva is the single phase enhanced

    I think now that 29kva on the application form is also SP CT metered

    Yours then is prob 3*12 KVA which is 36 kva

    I thought originally ESBN had basic 3P down as 29 but I think they're high capacity single phase supplies


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    #12
    st332
    Registered Users Posts: 147 ✭✭st332


    Zarco wrote: »
    16kva is the single phase enhanced

    I think now that 29kva on the application form is also SP CT metered

    Yours then is prob 3*12 KVA which is 36 kva

    I thought originally ESBN had basic 3P down as 29 but I think they're high capacity single phase supplies

    It looks like the installation on my side can handle e.g. a 22kW charger and a 29kVA MIC, but the connection was only set up for 16kVA MIC.

    Attached is the letter from ESB (minus personal details), which chimes with what the builder told me regarding the 16kVA MIC. Not sure why the "phases" field has been left blank.

    I guess the MIC could be upgraded but my point is that it wouldn't be worth my money doing so if the only effect of keeping it at 16kVA was some occasional throttling of car charging.

    The CT clamps I mentioned are part of the car charger I'm looking at buying (myenergi zappi). I don't think the ESB meter (Iskra MT174-D2A51-L11-M3K0) uses CT measurement.

    If, in the future, I have more than one EV or want to charge at 22kW, I could look into increasing the MIC.


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    #13
    Zarco
    Closed Accounts Posts: 112 ✭✭Zarco


    You don't have 16kva

    You've a 63amp 3P supply bout 36kva


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    #14
    st332
    Registered Users Posts: 147 ✭✭st332


    Zarco wrote: »
    You don't have 16kva

    You've a 63amp 3P supply bout 36kva

    I'm just concerned that the connection letter states 16kVA and if I exceed it, I could get landed with excess capacity charges. Maybe I should follow up with ESBN to see if it's an error.

    Thanks for all the advice, btw.


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    #15
    antoinolachtnai
    Registered Users Posts: 9,807 ✭✭✭antoinolachtnai


    Assuming your connection letter states DG1 or DG2 (domestic) or even DG5 (small commercial) you won't get excess charges.

    I would be surprised if your meter has any way of checking if you've exceeded the MIC.

    If you blow the fuse, of course, it's on you!


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    #16
    bobbyy gee
    Banned (with Prison Access) Posts: 1,306 ✭✭✭bobbyy gee


    3 phase
    https://www.irishevowners.ie/charge-points/


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    #17
    Lenar3556
    Registered Users Posts: 1,463 ✭✭✭Lenar3556


    The service fuses believed to be fitted and the contracted MIC are two different things.

    The MIC is 16kva as confirmed by the letter.

    That meter is in a position to detect exceeding MIC, but it’s not something they tend to get into for a domestic customer.

    Appears the supply will be more than sufficient for whatever you needs are likely to be. I wouldn’t be contacting ESB flagging any MIC concerns. What is the standing change on that supply out of interest?


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    #18
    st332
    Registered Users Posts: 147 ✭✭st332


    Lenar3556 wrote: »
    The service fuses believed to be fitted and the contracted MIC are two different things.

    The MIC is 16kva as confirmed by the letter.

    That meter is in a position to detect exceeding MIC, but it’s not something they tend to get into for a domestic customer.

    Appears the supply will be more than sufficient for whatever you needs are likely to be. I wouldn’t be contacting ESB flagging any MIC concerns. What is the standing change on that supply out of interest?

    €0.5479 / day


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