Can my electrician install a three phase supply?

Not the supply itself. The network operator owns the cables that bring energy to the property, so the incoming supply is theirs or an approved provider's work. Ofgem notes that a registered electrician can carry out some parts of connection work, called contestable work, subject to the operator agreeing or inspecting it. Everything from the meter position inwards is your electrician's job.

Who do I contact first for a three phase upgrade?

Your local distribution network operator, which is determined by where the property is. Ofgem's guidance is to contact the network operator to get electricity installed or to alter an existing connection, and to arrange the meter with an energy supplier at the same time to avoid delays.

Guide

Three phase upgrade: who does the work, DNO or electrician?

Updated 2026-08-14

Almost every stalled three phase job we hear about comes from the same misunderstanding: the customer briefed an electrician for a job that only the network operator can do.

The network operator owns the supply

Ofgem puts it simply: "Network operators own and run the gas pipes and power cables that bring energy to homes and businesses. In some cases, independent providers can do this. To get gas or electricity installed, contact your local network operator" (Ofgem). Your distribution network operator is set by geography, not by choice: you cannot shop around for a different one the way you can for a supplier.

You need a connection where you

build a new property or business premises
have no gas or electricity in the property
want to install your own generation
need to move an energy meter

An upgrade from single to three phase is an alteration to a connection, and Ofgem's direction there is the same: contact your network operator first.

Contestable work is where the competition lives

"A registered gas engineer or electrician can do some parts of the connection work (called 'contestable work'). This can help bring down costs, so it's worth asking for quotations to break down connection work into contestable and non-contestable costs. Network operators may need to agree or inspect this work." That single paragraph is the most useful cost advice on the subject, and it is why an independent connection provider or a contractor experienced with your operator can be worth more than a lower headline price.

Your electrician owns everything after the meter

Main switch and three phase distribution board, and the tails between them.
Earthing and bonding appropriate to the new arrangement.
Submains to outbuildings, workshops or charging points.
Balancing single phase circuits sensibly across the three phases.
Certification and notification of the installation work.

The meter is a third party again

Ofgem: "You will need to choose an energy supplier to get a meter installed. Arrange this at the same time as sorting your connection with the network operator to avoid delays. Your energy supplier will also bill you for your usage." It also states that it is illegal to move your own energy meter, and that if you want to move one you contact your supplier. Three organisations therefore have to line up: the network operator, your contractor and your supplier. Booking them in that order is the difference between a live supply and an energised cable behind a locked cabinet.

If something goes wrong with the operator, Ofgem publishes guidance on determination of disputes over use of system or connection to energy networks, and can resolve some connection disputes.