How much does it cost to add sockets to a room?

What you are actually paying for

Adding a socket involves getting a cable from an existing point to a new position, cutting in a back box, making the connection, making good, and testing and certifying the alteration. The accessory itself is trivial. Labour and access are the whole cost, which is why quotes vary so much between apparently similar jobs.

This is also why the second and third socket in the same visit cost far less than the first. The setup, the isolation, the dust sheets, the testing and the paperwork are largely fixed. If you are thinking about adding sockets anywhere in the house, do them in one visit.

• First socket carries the setup, testing and certification cost
• Additional sockets in the same visit are substantially cheaper
• Access is the variable: plasterboard is quick, stone and tile are not
• Making good and redecoration may be your cost, not the electrician's

Spur, extension of the ring, or a new circuit

A fused spur taken from an existing socket is the least invasive option and is appropriate for a single additional outlet where the existing circuit has capacity. It is not a licence to daisy chain: an unfused spur can feed one single or one double socket, and doing more than that is one of the most common faults we code on EICRs.

Extending the ring properly is more work but leaves a better installation where several outlets are being added. Where the demand is genuinely new, an office full of equipment, a garage, a kitchen refit, the right answer is a new circuit from the board, which costs more but is the only correct answer once the load justifies it.

What pushes the price up

Chasing into solid walls, particularly the stone and brick internal walls common in older valleys housing, is slow, dusty and needs making good. Running a cable behind a plasterboard dot and dab wall is quick. Lifting laminate or engineered flooring to run beneath, or getting into a loft with no boarding, adds time.

The other big variable is the board. If the circuit you are extending has no RCD protection, adding a socket to it means the new work must be protected, and that can mean an RCBO in the board or, where the board cannot take one, a wider conversation. Any quote given before someone has looked at your board is provisional.

• Solid walls, tiled surfaces and stone add labour
• Concrete floors and unboarded lofts limit cable routes
• Existing circuits without RCD protection may require board work
• Surface trunking is a legitimate cheaper option in garages and utility rooms

Ways to keep the cost sensible

Batch the work. Walk the house, list every socket you have ever wished existed, and get it all done at once. Be flexible on position where a metre either way avoids a chase across a chimney breast. Accept surface mounted trunking in utility spaces where appearance matters less. And do your own making good and decorating if you are comfortable with filler and a brush.

One thing not to economise on: never solve a socket shortage permanently with a bank of extension leads behind furniture. Sustained load through a coiled reel is a genuine fire risk, and it is a recurring finding in the incidents that fire services attend.

Certification and doing it right

An alteration to an existing circuit should be inspected, tested and recorded on a Minor Electrical Installation Works Certificate. A new circuit gets a full Electrical Installation Certificate and, in Wales, notification where the location or work type requires it, including kitchens and outdoor positions.

Keep those certificates. They are small pieces of paper that answer big questions at sale time, and they are evidence the work was tested rather than simply connected.