3 phase electricity supply

DrH2

We have extremely high electricity meter readings for our home which doesn’t make sense to us  and we have constantly questioned this with our supplier since moving in.

We inherited a 3 phase electricity supply to one meter which gives one meter reading. We have been advised by an electrician that a meter reading is obtained by taking the reading from one phase and tripling it. Obviously each phase of electricity supply covers different parts of the property and will use widely varying amounts of electricity, so this is concerning.

We had the supplier out to install a smart meter fitted but they cannot fit a smart meter to a 3 phase system. We were told by the electrician that came out, that the reading will be of actual usage across the three supplies but he was not familiar with this sort of supply and so we were not confident about what we were told.

We have not been able to get a breakdown of the usage to each phase.

Can anyone advise us on a 3 phase supply and how readings should be taken?

Should we have a meter for each phase of supply?

How can we check if someone else is feeding off our system?

all thoughts gratefully received.

Netexporter

A photograph of the meter and its tails would help. How many tails does it have?

Ectophile

It certainly shouldn't be measuring one phase and tripling it.  If it was, you could easily game the system by moving all your circuits to the other two phases, to get unlimited free electricity.

Netexporter

Presumably there is a three-phase supply because there are large loads, so you'd expect larger bills.

35har1old

DrH2 said:

We have extremely high electricity meter readings for our home which doesn’t make sense to us  and we have constantly questioned this with our supplier since moving in.

We inherited a 3 phase electricity supply to one meter which gives one meter reading. We have been advised by an electrician that a meter reading is obtained by taking the reading from one phase and tripling it. Obviously each phase of electricity supply covers different parts of the property and will use widely varying amounts of electricity, so this is concerning.

We had the supplier out to install a smart meter fitted but they cannot fit a smart meter to a 3 phase system. We were told by the electrician that came out, that the reading will be of actual usage across the three supplies but he was not familiar with this sort of supply and so we were not confident about what we were told.

We have not been able to get a breakdown of the usage to each phase.

Can anyone advise us on a 3 phase supply and how readings should be taken?

Should we have a meter for each phase of supply?

How can we check if someone else is feeding off our system?

all thoughts gratefully received.

If are using all 3 phases you should have a three phase meter which is a much large meter compared to a single phase.Pheraps you are only using one phase as some have asked for photo of the installion to see the layout.

markin

If each phase has a reading then you add them all up, But i would expect one off the displays is the total so no need to add them up.

Three-phase could mean the was in the past large loads as a farm or industrial but not always. If you have a heatpump, EV, or pool you could now have larger bills than a normal gas heated home.

rtho782

Getting one reading and tripling it is complete tripe.

Can we have a photo of the meter and supply?

Scot_39

Well known even with real 3 phase loads one reading doesnt guarantee accuracy.  It only works for the measurement of simple balanced loads in certain wiring configurations.  Saying that's the metering standard then seems a little strange.

This gets power geeky really quickly - so ignore unless an engineer

https://eepower.com/technical-articles/choosing-the-best-three-phase-power-measurement-method/

The main point is one phase reading isn't always enough.

2 or 3 readings are needed if loads unbalanced.

That however doesn't mean need 2 or 3 meters as data can be combined (in analogue world by wiring together old meter ct coils etc)


This link - from near top of google search - for modern digital 3 phase - specifically talks about readings for each phase voltage and current etc. And giving individual readings etc.

https://www.ytl-e.com/news/Knowledge/how-does-a-three-phase-kwh-meter-work.html


You might be able to find the spec for your meter on line which might help reassure you.

There are a few posters here with 3  phase domestic meters who should be able to confirm accuracy of their setup.

UncleK

We have two phases connected to our house - I have no idea of the history - but we thus now have a three-phase smart meter (fitted by Octopus a few years ago) and all is fine from a meter reading point of view (although it doesn't connect properly - another story).  The meter does not differentiate which phase it is metering - only between day and night rate.
When we moved in there were three old fashioned meters - one phase had two meters - one for day rate and one for night rate and the other phase had just a single meter. (The other phase isn't connected at all.)
Not sure it that helps any. It certainly sounds tosh that they "cannot fit a smart meter to a three phase supply".

FreeBear

UncleK said: It certainly sounds tosh that they "cannot fit a smart meter to a three phase supply".

Only a handful of installers will be trained on fitting three phase meters. So it is far more likely that they don't have a trained installer on their domestic team. Could also be a lack of three phase meters as well..

Strummer22

UncleK said:

 It certainly sounds tosh that they "cannot fit a smart meter to a three phase supply".

Yes, although a specialist fitter competent to fit a three phase smart meter will need to come out. My experience of smart meter installation companies is that they can't tell their a*rse from their elbow, let alone read the notes on the file stating whether the site has single phase or three phase supply.