Do you need help determining if your home or business uses single-phase, two-phase, or three-phase power?
Correctly identifying your power supply is often the first step to unlocking significant energy savings. With the right energy monitor or electrical sub-meter, you can track electricity usage, improve energy efficiency, and lower energy costs.
Here are two simple ways to check if your property has one, two, or three phases connected.
1) Count Your Service Fuses
A 'service fuse' is a large black rectangular fuse. Service fuses are generally easy to spot on your main switchboard or meter board.
The relationship between service fuses and 3 phase power is pretty simple:
- Single phase = one service fuse,
- Two phases = two service fuses,
- Three phases = three service fuses.
A household with a 3-phase power supply. Note the three service fuses at the top left of the board.
2) Check Your Main Switch
Another way to separate three phases from a single phase is the width of your main switch. Single-phase switches are 'one pole' wide, whereas 3-phase switches are 'three poles' wide. See the picture below for what I mean.
Single-phase / single-pole main switch (on the left) vs. a three-phase / three-pole main switch (on the right).
These 'Main Switches' are usually found on your meter board. You can also find main switches on each sub-board or distribution board in larger premises or unit blocks.
What About Single or 3 Phase Solar Power?
Much like the above, you can work this out by observing the 'Solar Main Switch' as per the examples below.
Single-phase solar (left) vs 3-phase solar (right).
What About 2 Phase Power?
Two-phase power supplies are also quite common in Australia. Two-phase power has two service fuses rather than one or three. See the example pictured below.
Can I Have More Meters Than Phases?
Yes. It's not uncommon to have one more meter than the number of phases you have connected. So you can have four meters at a three-phase site or two meters at a single-phase site. The reason is usually separately metered off-peak hot water.
Here's a two-phase site with three electricity meters. We know it's two phases due to the 2-pole main switch (bottom left) and two service fuses (top).
My Utility Meter Says '3 Phase', Do I Have 3 Phase?
Not necessarily. You can have a three-phase enabled electricity meter with only one of two phases connected. That's why my guide above says to check your Service Fuses and Main Switch - not what's written on the meter!
Which Energy Monitor or Meter Should I Use?
Now that you know what type of power supply you have, you can delve further into your electricity usage.
An electricity monitor is an essential tool that gives you a real-time display of your electricity usage. On the other hand, an electricity sub-meter is a hard-wired device that sits at your meter board (it's more accurate and often used for on-billing).
Here are some links to our energy meter and monitors:
Note: if you have two-phase power, install a 3-phase device and leave one phase unused.
