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3 phase 100A power supply - voltage at each phase goes up to 250+ Volts should I be worried?

Former Community Member
Former Community Member
New 3 phase power supply installed and live from an ICP (independent connection provider) and meter installed, the service is all sealed up and live.


My NICEIC electrician has now installed an 18 way distribution box after the 4 pole isolator from meter tails and everything seems to be all ok, we also made sure to achieve compliance with 18th edition amendment 1 as I have an electric vehicle on the property that will be charged.


I also got a 4 pole Type 1 surge protection device to be installed (Hager JK101SPD) in-line with the mains incomer so that all the ciruits behind it will be protect.


The car is protected behind a Type A and Type B RCD which is 4 pole and 40A (as per the manufacturer's guidelines). The charger also has other safety features such as earth monitoring and neutral-earth fault detection.

However, the car shows at peak and middle of the night the voltages around constant at 250V and sometimes sits as high as 257V (does not seem to go beyond that).


Is this something I need to be worried about? Or should be I be okay?


Appreciate your insights please.


Parents
  • 0
    If these voltages are reported by the car software, they may not be that accurate  (5 to 10% off does not affect the cars internal 'is it OK to charge' decision)- if you are concerned, a then a comparison with readings from a proper meter is needed.

    Officially the supply may be 230V +10%-6% , so 253 would be the upper bound for 'normal' operations.


    In use quite a bit of voltage variation is not normally a  problem unless there are other indications the voltage really is a bit high, the classic used to be failing light bulbs, but less so nowadays with electronically ballasted LEDs and so on.

    It may be set up wrongly if a new transformer has gone in to support your supply, and the wrong tap connections  have been set, or if for some reason lots of generation has been added to your substation (I'd think solar panels as a source of voltage rise, but obviously not if the volts only go up at night ?.)

    Before panicking, I suggest a cross check with a real meter, or seeing what the car  reports when charging elsewhere.

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  • 0
    If these voltages are reported by the car software, they may not be that accurate  (5 to 10% off does not affect the cars internal 'is it OK to charge' decision)- if you are concerned, a then a comparison with readings from a proper meter is needed.

    Officially the supply may be 230V +10%-6% , so 253 would be the upper bound for 'normal' operations.


    In use quite a bit of voltage variation is not normally a  problem unless there are other indications the voltage really is a bit high, the classic used to be failing light bulbs, but less so nowadays with electronically ballasted LEDs and so on.

    It may be set up wrongly if a new transformer has gone in to support your supply, and the wrong tap connections  have been set, or if for some reason lots of generation has been added to your substation (I'd think solar panels as a source of voltage rise, but obviously not if the volts only go up at night ?.)

    Before panicking, I suggest a cross check with a real meter, or seeing what the car  reports when charging elsewhere.

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