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Sub-meter FAQs

An electricity subsidiary meter (sub-meter) is a meter that allows for the monitoring of electricity usage on a portion of your private installation past the revenue meter. Typical users of sub-metering are residential properties with a granny flat, apartment buildings, shopping centres, mobile home parks and commercial buildings.

The revenue meter records the total consumption and the sub-meter records the part consumption for the sub-metered area only. Thus the sub-meter’s consumption is recorded in the revenue meter. 

Sub-meters are typically privately owned and are not part of the Western Power network. Sub-meters include:

  • meters purchased from Western Power when the customer’s multiple revenue meters were converted to sub-meters with the installation of a single revenue meter
  • meters where ownership has been transferred from Western Power to privately owned.

Western Power has no statutory or regulatory obligation to read sub-meters. Customers with sub-meters requiring sub-meter readings should engage the services of a private meter reader if they are not able to read it themselves. We recommend that sub-meter customers consult with the revenue meter customer to arrange a suitable private meter reader should they require reads.

Yes. If you want to install a new sub-meter or replace an existing sub-meter you can arrange this through a licensed electrical contractor. A Western Power owned meter cannot be used. You are able to purchase a meter privately from a meter supplier.

An existing sub-meter can be replaced at any time by engaging a licensed electrical contractor.

You need to engage a licensed electrical contractor for a new meter and the meter replacement service.

You will need to engage a licensed electrical contractor to perform the meter removal.

Western Power has no statutory or regulatory obligation to maintain or replace sub-meters or any part of your installation.

The sub-meter owner is responsible for maintaining the meter. The maintenance may be arranged through an electrical contractor or consultant.

You will need to engage a licensed electrical contractor to perform the necessary wiring changes, and open a new account with your electricity retailer for each new revenue meter.

You can have a licensed electrical contractor perform a sub-meter test. Western Power has no statutory or regulatory obligation to perform a sub-meter test.

The revenue meter is required to be changed or reconfigured to measure bi-directional energy flows (import – export meter registers) before the connection of the embedded generation system. Please contact your electricity retailer before applying to Western Power for technical approval of your proposed system.

If a sub-meter is associated with the connection point at which bi-directional flows will occur, you may wish to engage a licensed electrical contractor to change the sub-meter and make the necessary arrangements with you at the revenue meter.

If bi-directional flows will occur at a sub-meter the measurement of energy flows is at the discretion of the customer. You may wish to engage an electrical consultant or contractor for energy management options.

Common sub-metering arrangement

The diagrams below illustrate typical revenue meter and

sub-meter configurations.

Residential property with granny flat

Residential property with granny flat

Apartment buildings and shopping centres

Apartment buildings and shopping centres

Power station

Power station

Note: SPD means Service Protection Device.