Can I get 3-phase power at home? We asked an electrician

3-phase power supply at home

The short answer is yes, you can get 3-phase power at home. Electricians can handle the electrical work but they are not allowed to change the supply, which is done by the distribution network operator (DNO).

The extent of electrical modifications required to deliver three-phase power depends on the configuration of your property.

How to get 3 phase power at home

To get 3-phase power at home, you’ll need to contact your electricity Distribution Network Operator (DNO) to request an upgrade. An electrician can handle this application for you. Be prepared for extensive electrical modifications, as 3-phase requires different cabling and infrastructure than single-phase. The DNO will likely need to dig trenches to access and replace the underground supply cable to your property. Once new 3-phase cables are installed, your electrician will mount a new meter box and distribution panel, and rewire your home’s circuits. Finally, your energy supplier will swap the old meter for a 3-phase compatible one. The process involves coordination between you, your DNO, electrician and energy provider. Costs often exceed £3,500 due to the complexity. Upgrading is worth considering if you need over 7.4kW to power high-drain appliances or electric vehicle chargers.

A 3-phase power supply is a type of electrical supply that consists of three active conductors, each providing power at a different voltage. The three phases are typically labelled A, B and C, and the power is usually supplied at a voltage of between 208V and 480V. This type of power supply is commonly used in industrial and commercial applications, as it provides a more reliable and efficient source of power than a single phase supply.

Most houses in the UK have a single-phase power supply, which is sufficient to power a 7.4kW EV charger but nothing more.

If you want an 11kW charger for an EV, you must upgrade to a 3-phase power supply, which requires modifications to your electrical installation.

Can you go from single-phase to 3 phase?

Yes! Any competent electrician can upgrade your property to three-phase, although electricians are not allowed to change the supply. This must be done by the distribution network operator (DNO). You can get a 3 phase connection for home but you need to apply to the DNO and collaborate with local authorities.

Cost of installing 3 phase power UK

The cost of upgrading to a 3-phase electricity supply in the UK often exceeds £3,500 plus VAT due to the complexity of the required work. Exact pricing depends on several factors. Distance to the nearest 3-phase supply affects cost, as more trenching and cabling are needed the farther away it is. Location also matters – if digging through public land, council permits, parking suspensions and traffic control add fees. Inside your home, a new distribution panel, rewiring and a 3-phase meter add expense.

Additional costs come from hiring an electrician to handle the technical modifications and coordinating with your Distribution Network Operator and energy supplier. £4,000 including VAT is reasonable for a standard 20 meter cable run conversion. For larger sites like farms, quotes over £7,000 are common. While not cheap, 3-phase allows for high power applications like electric vehicle chargers over 7.4kW.

We asked eco-EV Ltd, a charge point installer in Hull, about the extent of the work required to go from single-phase to three-phase.

“There are many variables involved in converting single-phase to three-phase, and that’s why you don’t see electricians publishing workflow guidance because no two jobs are the same. Having said that, there are several things you may not know about the work required.”

“The first thing to note is that anyone wanting to upgrade to a 3-phase supply would need to make an application to the DNO, but their electrician can handle the application,” says Paul Walsh, MD of eco-EV Ltd.

“Three-phase installations are structurally different to single-phase, so the existing single-phase fuse and cabling running to the property need replacing. In most homes, in the case of cabling, this means trenching [digging] back.”

“Trenching is time-intensive, sometimes at a depth of 60cm for several metres. We need a trench to make a line for the new cabling and to connect that cabling to the 3-phase supply. Sometimes you get lucky and the supply is only a few metres away, but there isn’t always a 3-phase supply located nearby.”

“Thankfully, the existing wiring in a modern house is compatible with a three-phase supply, so really, only the cabling supplying the property needs upgrading along with the distribution board.” Paul adds, “the unit needs replacing with a three-phase distribution board with RCD protection, to meet regulations.”

Next, we asked Paul to clarify the core differences between single-phase and three-phase power, to give us a better idea of the size of the project.

“Three-phase power is a four-wire circuit, with three power wires and a neutral wire. Compare that to single-phase power, which is a two-wire AC power circuit, a power wire and a neutral wire, and you can see why the work required to convert single to three-phase can be intensive.”

“The existing distribution panel needs to be removed and a new 3 phase panel added with the loads ‘balanced’ across the phases including the EV charger installation. This is the correct approach for a safe, professional installation.”

“Replacing a distribution board like-for-like for another is easy work for a competent electrician, but with three-phase, it’s the added complexity of the wiring that adds time to the process. It takes longer to wire up and test. Safety always comes first.”

Single to three-phase cost

Next, we asked Paul about the cost to go from single-phase to 3 phase. How much will a customer pay?

“It almost entirely depends on how far away the 3-phase supply is. If you’re a few miles away from a 3-phase supply then the project won’t be cheap. However, if we are talking up to 25m then we’re in business.”

“£4,000 including VAT for a standard conversion with up to 20m of trenching sounds reasonable,” says Paul.

“It isn’t unheard of for electricians to quote £7,000 to £15,000 for some projects, with higher price brackets for farms and larger buildings.”

“Unfortunately, if you want an 11kW or 22kW EV charger, 3-phase is absolutely necessary. We expect more people to upgrade to 3-phase with the transition to electric vehicles. It’s the price you pay for higher energy use.”

“Upgrading to 3-phase power can seem complicated, but it may be worth it if you need more power. Let’s break it down step-by-step so you know what to expect.

How to tell if you have three-phase already?

You can tell if you already have 3-phase by checking a few things:

  • Your fuse board – if there are 3 main fuses, that’s a sign of 3-phase.
  • Electricity bill – some suppliers list the power phase.
  • Meter – it may say something like “poly-phase” or “tri-phase”.

If you see only 1 main fuse at the fuse board, you likely have single-phase.

Now for the upgrade – first contact your DNO to make sure it’s possible. If so, expect lots of digging! They’ll need to access the underground cable to your property which means trenching your front garden or driveway.

If the cable also serves neighbors, the work may extend to their property. Any digging on public land requires council permits too. And if roads are closed, traffic control adds cost.

Once cables are replaced, a new 3-phase meter box gets mounted on your exterior wall. After connections are made, the DNO will test for safety. Holes get filled eventually, but maybe not right away.

Last, your energy supplier swaps the meter to complete the job. Make sure to schedule them the same day so you’re not without power!

Whew, it’s not a simple endeavor! But there are good reasons to upgrade:

  • More power – 3-phase provides higher voltage for EV chargers, heavy appliances
  • Consistent flow – fewer fluctuations than single-phase
  • Reliability – less prone to outages with steady delivery

Just be prepared for a hefty price tag. Costs often exceed £3,500 plus VAT.

Why such a cost? Complexity really drives the cost. Permit fees, traffic control, parking charges all add up. The more digging through public areas, the more headaches.

In the end, 3-phase installation takes coordination. You need approval from the DNO, permits from the council, and scheduling with your energy supplier. But if you need serious power, it may be worth the effort!

If you’re interested in pursuing job opportunities for electricians, you can find a range of options on Jooble. It’s a great career, especially with electric vehicles taking off.

Installing 3-Phase Power – The Process

Here’s what converting a single-phase supply to a three-phase supply looks like:

What you’ll need before starting

Before installing 3-phase power in your home, assemble the necessary equipment:

  • 3-phase energy meter
  • Molded case circuit breaker (main switch)
  • Double pole switches
  • RCDs (residual-current devices)
  • Appropriately sized power cables
  • Electrical safety gear – gloves, glasses, boots, etc.

For a single meter under 7.5kw (10HP) load, stick with standard single-phase. Over that, install a 3-phase meter to regulate higher power consumption.

Safety precautions

Take these precautions when working on electrical wiring to avoid harm:

  • Completely disconnect the power source before starting.
  • Use cable sizes appropriate for the electrical load.

Following basic safety will greatly reduce any risks.

Installation steps

  1. Connect the 3-phase meters at the correct points to prevent faults.
  2. Connect the molded case circuit breaker as the main switch for the phases.
  3. Connect the outgoing phases from the circuit breaker to the double pole switches.
  4. Connect the neutral wires to the RCDs (for ground fault protection).
  5. Link the neutrals together and connect them to the loads.

Alternate wiring methods

A 4-pole circuit breaker can also be used instead of a 3-pole version. Just connect the neutral wire to the last slot on the 4-pole breaker.

For 3-phase wiring, line-to-line voltage is 440V and line-to-neutral is 230V. Follow all code requirements.

With these tips, you’ll be ready to safely install 3-phase power in your home! Let me know if you have any other questions.

Upgrade main fuse from a 30 or 60amp fuse up to an 80amp or a 100amp fuse

If your single-phase electrical supply has a 60 amp or lower fuse, you can upgrade to an 80 amp or 100 amp option instead of converting to 3-phase. This allows more power for high consumption appliances and EV chargers without the complexity of a 3-phase upgrade. To increase your main fuse amperage, contact your Distribution Network Operator (DNO) to request the change and arrange for them to replace the fuse. An electrician can handle this for you. The DNO may need to install a thicker supply cable if the existing one is undersized for the new fuse rating. Your electrician will fit a compatible fuse box and wiring suited to the increased amperage. Costs are lower than a 3-phase conversion, with pricing starting around £1,500.

The bottom line

Yes, you can go from single to 3-phase. To upgrade to 3-phase, you need to make an application to your DNO, but your electrician can handle the application.

The cabling supplying your property needs replacing and a three-phase distribution board with RCD protection needs installing to balance the various loads.

Is upgrading to a three-phase power supply worth it? Only if you need it. A single-phase supply will power an EV charger up to 7.4kW.

We extend our thanks to ecoEV Ltd for helping us produce this resource.

I hope you enjoyed this article and it helps you out. If you have any questions, share a comment below. Thank you.

Jakk is the founder and chief editor of Top Charger. He drives a Volkswagen ID.3 Family Pro Performance, and despite having a lead right foot, he consistently gets over 200-miles of range.