3-Phase Upgrade Questions

  • NotAnInterestingName's Avatar
    I'm currently at the application stage of asking Western Power to upgrade our supply from a single phase 100A to a three phase 3x 100A supply. Our supplier is Eon Next. We're doing this in readiness for two heat pumps and car charger(s) that will follow later.

    I'm thinking about moving the meter from where it currently is within the middle of the building next to the consumer unit, to closer to where the cable currently enters the building. This is partly because space is limited where it currently is, presumably the new equipment will be bigger, and we'll now need three consumer units instead of one so the space currently occupied by the meter board would be very useful for this. Also I really don't like having a completely unfused cable running through the loft, although it is armoured so should be fairly safe but it still doesn't seem like a clever idea.

    So, hopefully the new 3-phase meter will be fitted in a new location, next to where the existing feed to the meter is. There is already a (1990 era) 100A cable from here to the old meter. Can this cable be connected to one phase of the new meter, and the old meter either bypassed or just left and ignored? This would give us everything we already have, all connected to one of the phases.

    I appreciate that eventually we will need all three phases wiring through, but this would give us power on the day without too much upheaval.

    I do appreciate that this wouldn't be ideal, to put our entire load on one phase. But this would allow us to have everything up and running, ready to start adding new things and transferring some old things to the other two phases in future.

    Does this sound like a sensible plan, would it be allowed, and whose job would it be? Western Power, Eon Next, or an electrician?

    How is the job coordinated? Presumably someone for Eon will need to fit the meter on the day that Western Power are digging up the street, otherwise we'll be left in the dark. Or do Western Power fit the new meter?

    Also, will the switch to 3-phase affect my bill at all? E.g. standing charge or any other extras?
  • 5 Replies

  • NotAnInterestingName's Avatar
    I'll simplify my question, as my original post was too long...

    Will Eon Next charge any extra per month for us having a three-phase supply instead of single phase?
  • theunknowntech's Avatar
    Level 78
    Hi @NotAnInterestingName,

    I'm theunknowntech and I'm a forum volunteer around here. My full reply will be posted soon but I'm on my phone right now and need to grab my laptop to reply properly. Hang in there for a bit and I'll be with you shortly. But for now, the short answer is you'll only get charged extra if you're using more energy.

    Just another guy passing by... The unknown tech way...
    Pete is an IHD Tariff Update Robot! 🤖 Anasa is a Giant Enemy Robot Spider 🕷 🤖 Hannah is neither! Need Customer service? click here! Replacement IHD Guide? Here it is!
  • NotAnInterestingName's Avatar
    Great, that's good. I didn't want to end up paying a standing charge for each phase, or switch to a commercial tariff, that would be very upsetting!

    I'll ask Mr Western Power all the techy questions about who does what and what's possible when he visits to survey the place.
  • theunknowntech's Avatar
    Level 78
    No worries. You actually only pay one standing charge per MPAN and per MPRN, each of which are usually only attached to a single meter. :)
  • Beki's Avatar
    @NotAnInterestingName Thanks so much for asking your question on our Community 😊 Did @theunknowntech answer your question?
    If so, could you pop back and verify their answer please? You can do this by pressing the 3 dots to the right and selecting verify answer.
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