Single phase and three phase electricity supplies: How to identify your supply and request an upgrade or downgrade

  • 28 October 2020
  • 13 replies
Single phase and three phase electricity supplies: How to identify your supply and request an upgrade or downgrade
Userlevel 7

Updated on 07/03/23 by Emmanuelle_OVO


Single phase and three phase electricity supplies - Your guide



How to tell if you have a three phase meter



Requesting an upgrade to a three phase supply


  1. If you’re increasing the electricity demand required in your home (eg by installing multiple EV chargers or a new electric heating system) an electrician can advise whether you might need to upgrade to a 3 phase supply.
  2. You’ll then need to contact your Distribution Network Operator (DNO) to schedule an engineers visit to upgrade your main fuse to 3 phase fuse.
  3. As your supplier, we can then book a 3-phase meter exchange (Currently this would be a traditional meter although we have started testing 3-phase smart meters) for a 3 phase trained engineer to upgrade your meter at the cost of £325 - Check out our full guide to 3 phase meter maintenance costs here.

We’ll provisionally schedule your appointment with at least 20 working days notice, however as the availability of specialist 3 phase engineers can vary depending on your area, SMS (our third-party contractors) will get in touch with you directly to confirm this appointment date.  Once the meter has been installed you may also need to enlist an electrician to re-connect your consumer unit.


Do OVO offer 3 phase smart meters?


3 phase (aka polyphase) installations in domestic properties are few and far between, so it's a minority of meter engineers across the country that have the skills required to complete these installations. There are also some technical challenges in making sure your job is allocated to an engineer with these skills but we are just as keen as you are to have Smart available for these sites ASAP, so if you would like to take part in this beta stage release, please consider the steps below:
From the start of May 2023, if you have a single rate 3 phase meter (i.e. not Economy 7 / 2-rate etc.) we would encourage you to book a smart meter appointment as normal online or over the phone on 0330 303 5063. (Please do not attempt to book sooner than May unless you have been contacted.)

This will then go through to a specialist team who will validate that it is single rate job and that an 3 phase engineer is available in your region. If this is the case, they will re-book your appointment with the right engineer. (So please bear in mind your appointment date/time will likely change, but we'll try to keep it the same where possible.)

Unfortunately, if you have a 2-rate meter or are not in an area covered by our current crop of 3 phase skilled engineers, you will need to continue with your heritage meter. We know this will be frustrating, so we are sorry about that, we are working to expand our coverage and by you flagging your interest to us, you are helping us shape where and when that coverage develops. - thank you!


The process for downgrading your supply to single phase


  1. In the same way you would for a 3 phase upgrade, if you think you no longer need this higher capacity supply (for instance you’ve removed a high usage appliance) you’d need an electrician to confirm this.
  2. Again you’d need your DNO to replace your fuse to a single phase fuse.
  3. After the fuse has been replaced, as your supplier we can then arrange a meter replacement. As this work would also require a 3 phase trained engineer, it’s booked at the same cost and with the same time frame as an upgrade. A downgrade of your supply would also mean you’d be able to get a new SMETS 2 meter installed.


Looking to upgrade or downgrade your supply and need some advice? Comment below! There’s plenty of energy experts here who’d love to take a look and help where we can. :slight_smile:

13 replies

Userlevel 1

While we are still in the middle of trying to establish a correct  assessment of an OVO customers issues, over billing , lack of transparency, failure to comply, we come to the subject of Smart Meters and an engineering overview. In a recent conversation with customer services we asked for an appointment  for an engineer to assess the present metering set up with a view to adding in Smart Meters and clarifying the accuracy of the present metering arrangements. After all the meters may be more than 60 years old. The advise given was “Get a local engineer to look it over and pay for his assessment” . That does not sound like a Three Phase review is desirable to OVO. Has anyone else encountered  a negative response to a request for an engineer to review an installation?


Userlevel 7

Hi @3Phasesupplies,


OVO would be able to arrange a ‘technical site survey’ for £106 as outlined in this job list: 



Perhaps it’s this cost that made the agent you spoke to suggest an electrician visit.


Please note that if you have a 3-phase supply, we may not be able to book in a smart meter exchange on request, as we’ve only got a small number of trained poly-phase smart meter engineers operating on a trial basis. I’ll make a note of your username and will reach out when we open up availability for these appointments nation-wide. 

Userlevel 1

Tim.  Something is wholly missing in the multiple exchanges posted. I will try to be brief and to the point. We have 5 single phase meters. One three phase supply. The property HAD repeat HAD circuits that we three phase operational. These are no longer in use but the meters show CREEPAGE. We asked the agent to book an engineer to give a technical assessment of the current installation and if the meters were CREEPING. The installation is over 60 years old. Meters do fail or go wrong. We would still like an engineer booking but sometime in 2024 is not a response we appreciate. It has nothing to do with cost. It would appear to be OVO happy with the status quo and not wishing to be active in correcting known errors in account management billing and meter reading / maintenance. If i could DM you all would become clear.

Userlevel 7

Hey @3Phasesupplies,


That seems like an extraordinarily long timeframe for a site survey. 


I’ll get Forum_Support to send you a message, please keep an eye on your private messages.

Userlevel 1


Booked OVO to install a new 3 phase meter, didn't show up to fit the new meter after SSEN disconnected the single phase and now without power heating or water (well pump not working. So called emergency engineer didn't turn up. How do I get in contact with an engineer? 

Userlevel 7
Badge +2

Booked OVO to install a new 3 phase meter, didn't show up to fit the new meter after SSEN disconnected the single phase and now without power heating or water (well pump not working. So called emergency engineer didn't turn up. How do I get in contact with an engineer? 

@Tim_OVO @Emmanuelle_OVO 

Userlevel 1

Interesting that you could book an engineer from OVO to install a 3 phase meter. I made a request some time ago was advise “Ovo don’t have enough engineers to do the installation and would advise me when they did.


See Tim_OVO from two months ago.

Still no word on a three phase meter installation. I was advised by Customer Services to ‘Find another supplier”

Userlevel 7

Hi @GuzBristow1, please see my response to this here:



@3Phasesupplies I suspect the 3 phase meter booking isn’t for a smart meter. We can book in non-smart 3 phase installs, and are in the process of scaling smart polyphase (including 3 phase) as well. 

Userlevel 1

Thanks Tim_OVO

The  meters installation really does need a review. 5 single phase meters. 1 three phase supply. 5 meters to read every month and post the readings on line, every month. Either a Polyphase solution or Smart meter when available would be perfect. But of course perfect doesn’t exist.

I have been waiting 10 months to get a polyphase meter to replace the single phase meter I have currently.

I have been to the ombudsman, had my complaint upheld, finally got an appointment for last week. No-one turned up. I am now back to square one being told there are no available appointments. 
I am at the end of my tether and can’t wait for this work to be done - dues anyone have any idea what I can do now???

Userlevel 7

Hi @KStewart17 and thanks for flagging this one.


Sorry to hear about the missed appointment. If you weren’t given at least 24 hours notice of the appointment not going ahead, you’ll be owned compensation. If it isn’t paid promptly, it gets doubled. That’s only a silver lining, I know you would prefer a polyphase meter. 


We’re rolling these out at a small scale at the moment, as the volume of polyphase trained engineers is still low. But getting better. You should have a complaint handler that worked your Ombudsman case that you can contact about this. As it’s directly related to your complaint and remedy, that channel is still open to you and may help to avoid you having to chase up for an appointment. 

Thanks for your message I have been to the ombudsman, had my complaint upheld - but it has made no difference as in there words they don’t have control over the scheduling of appointments. Brings into question what the ombudsman is there for to be honest.