Understanding Single and 3 Phase Electrics

If you’re considering hiring an electrician, you may have concerns about understanding the terminology used.

Although all our recommended electricians are happy to take the time to explain what is involved in a project, many people find themselves feeling a little embarrassed to ask.

Single and Phase 3 electrics is one of the most commonly misunderstood areas of electrical installation, so here we’ll explore this topic further so you can develop a basic understanding.

Simply put, single phase electric uses only one Live wire which is mainly found with domestic electrics, while as the name suggests, 3 phase uses three live wires and this is most commonly found with commercial electrics. However, both of these options use a neutral wire and in almost every situation an earth wire.

The main reason why 3 phase is used is that it offers a more reliable, constant current.

For this reason, it is often used on powerful commercial appliances, such as catering equipment, but it can be necessary for more power hungry kitchen appliances and other applications around the home.

In most cases, single phase machines that are up to 13 amp rating will be fitted with a three pin plug. Single phase appliances and devices over the 13 amp rating are usually not supplied with a plug and need to be hard wired to a suitable power supply by a professional.

3 phase machinery is usually hardwired, but some commercial properties, such as commercial kitchens may be equipped with 3 phase commando plug outlets. These are industrial graded sockets and plugs that are designed to transfer larger amounts of power safely.

While you may see an Amp rating on many devices throughout your home or business, you may not appreciate what this actually signifies.

All electric appliances display an ampere rating. This is often shortened to just amps or even an “A.”

In simple terms, amps are a measure of the electrical current the machine uses when it is run at full power.

For example, a four slot toaster may have a rating of 10A. This type of machine is usually single phase and fitted with a standard three pin plug. For safety reasons, the plug will be fitted with a fuse that protects against any electrical surges.

Although it may appear just a larger version of this appliance, a commercial eight slot toaster could be rated at 20A. This has double the output and requires more power than is provided using a standard plug. So, while this type of toaster may still be single phase, it will need to be hardwired to the power supply.

In commercial settings, a highly powerful combination oven may have a rating of 3x49A. This is a three phase piece of equipment with each “phase” needing 49 amps. This adds up to a total load of 147 amps. This would obviously be one of the most demanding appliances in the kitchen.

Therefore, in this situation, the maximum load of the electric circuit in the kitchen would need to be calculated to ensure that it is not being overloaded.

Fortunately, for this or any other electrical installation, all our recommended electricians can perform any calculations and ensure that any new appliances can be accommodated by the electrical circuit in the room.

If you have an appliance that needs connecting to the main but not sure what is required, contact our recommended electrician in your area and they'll be happy to assist you.  You can find them here.