Single-phase and three-phase electricity are electrical systems that deliver different amounts of power. Most household needs in the UK are covered by single-phase electricity, which provides sufficient power for the average home’s lighting, kitchen appliances and other electronic gadgets.
Single-phase electricity is usually fitted in homes with gas central heating that has one electricity meter. However, the demand for electricity in our homes is increasing.
We discuss three-phase electricity, and whether you need to install it in the home.
What is the difference between single-phase and three-phase electricity?
Most UK homes have a single-phase electricity supply of 60, 80 or 100 Amps which is usually supplied at 230 volts and will have one electricity meter box. It is unusual for commercial or industrial buildings to have single-phase electricity. Single-phase electricity is delivered in cycles of around 50-60 times per second, so at times of periods of peak demand there may be a reduction in power.
Three-phase electricity is necessary when there is higher than average demand. It is essentially three electricity supplies in one. The three phases are fixed to deliver peak power at different times at different stages of a full cycle, which ensures that the supply is consistent with no reduction in power. Any electrical equipment will be connected to one of the three supplies, spreading load across the three phases and balancing the appliances against each another so that there are never too many connected to any one phase.
Why might I need three-phase electricity?
The choice between single-phase and three-phase supply is dependent on the specific requirements of the property. Larger homes and commercial or industrial buildings might require a greater amount of electricity, more consistent power delivery or more than one meter. These, and homes with a stair lift, heat pump or electric car charger, are more likely to need a three-phase electricity supply.
A qualified electrician will assess all the equipment you run to determine how much power you require.
Three-phase may be more efficient, but single-phase supply is usually sufficient for residential property where power demand is lower. Single-phase supply is available in most residential areas and is more straightforward to install and maintain. It also requires less expensive wiring and equipment.
Three-phase supply is less commonly available in residential areas and requires additional wiring and equipment.
Can electricity suppliers cope with higher demand?
There is an argument to say that all new homes should be built future proofed. This may mean that the installation of three-phase electricity should be considered to become standard in all new construction. This by itself will not increase demand from consumers, nor increase the immediate necessity for supply. However, should the electrical needs of a typical home suddenly require greater supply than can be provided by a single phase supply, then the infrastructure will already be in place.
“the largest overhaul of the UK’s electricity transmission grid in generations – represents a significant shift in infrastructure development. Joseph Northwood, Director of Portfolio Development and Strategy, said: “Over the next decade we will be undertaking one of the biggest ever infrastructure build outs in the UK, with 17 major onshore and offshore projects to deliver. That is the step change required.”
It estimates that the UK needs to increase electricity transmission infrastructure by five times in the next six years than has been constructed over the past three decades. On a positive note, it says the Great Grid Upgrade could create 130,000 jobs and contribute up to £11 billion to the economy.