Electricity power available in my home?

  • During normal energy use, the power supplied by your electricity meter (18.4 kVA on average) should be sufficient. In theory this allows you to simultaneously supply appliances with a maximum power of 18.4kW or 18,400 watts.
  • If you have special installations that consume a lot of energy, such as a sauna, pottery kiln or electric vehicle, then that power might not be sufficient.

How do I calculate the maximum power that my electricity installation can supply?

To calculate the maximum power your meter can supply (expressed in volt-amperes), multiply the voltage (U) by the intensity (I) of the current which supplies your home.

  • The majority of homes in England are supplied with 230 volts (V) single-phase with an intensity of 80 amperes (A). The maximum capacity is therefore 230v x 80 A = 18,400 volt-amperes (18,400 VA) or 18.4 kVA.
  • The formula used to determine the capacity for a three-phase connection of 230 V, or 400 V is identical, i.e.: √3 x 400V x 25A = 17,300 VA

(*) For quick calculations or for the sake of convenience, √3 is often replaced with the approximate value of 1.73. We have used the same number here as well. Fun fact: the difference between both outcomes is a factor 1.73! This is explained by the fact 400V voltage also happens to be 1.73 greater than 230V.

How do I know if my meter’s electricity power supply is sufficient?

If you require more electricity power than your meter can supply, the power main switch on your consumer unit will trip to secure the installation due to an overload. The main cut out fuse may also blow.

If the main cut fuse blows, this indicates your installation has insufficient power for your requirements and you will have to contact Western Power Distribution to replace the main cut out fuse to restore your electricity supply.

What meter power (in kVA) for which intensity (amperes)?

The more voltage and intensity, the more power your meter will require. The table below displays the power required to supply the intensity you need.

AmperesPower in 230V single phase           (in kVA)Power in 230V three-phase               (in kVA)Power in 400V three-phase           (in kVA)


How can I increase my electrical installation power?

If you would like to increase your electrical installation power supply? Please first ask Plymouth electrician: – Goodwin Electrical for free advice by filling in our contact form at: – https://goodwinelectrical.com/contact-us/ We can provide the most appropriate solution for your needs. There are 2 possibilities:

  • Increasing the meter’s power (if your electrical installation can handle this) and remaining single phase.
  • Switching to three-phase power and potentially increasing power.


main electricity switch


For these modifications you must always contact Western Power Distribution (DNO for the South-West) – https://www.westernpower.co.uk/connections-landing/connecting-dwellings-or-commercial-premises/apply-online-for-a-new-connection

Western Power Distribution is responsible for electricity connections, independent of your energy supplier.

Although you will be billed for the installation costs, this will not affect your monthly invoice from your electricity supplier.