Spur a Socket — Cost Calculator
Add a fused connection unit (spur) from an existing ring main socket to power a new outlet, appliance, or switched fused connection unit.
Your Project
Quality tier
Price Comparison
| Item | Retailer | Qty | Unit | Line Total |
|---|---|---|---|---|
| Cable & Wiring | ||||
| 2.5 mm² Twin & Earth Cable10 m coil | Screwfix | 1 | £12.49 | £12.49 |
| Fused Connection Unit | ||||
| Switched Fused Connection Unit (13 A)1 unit | Screwfix | 1 | £4.99 | £4.99 |
| Back Box & Containment | ||||
| Surface Pattress Box (1 Gang)1 box | Screwfix | 1 | £1.39 | £1.39 |
| Mini Trunking (16 × 16 mm)2 m length | Screwfix | 2 | £2.69 | £5.38 |
| Tools & Sundries | ||||
| Non-Contact Voltage Tester1 tester | Screwfix | 1 | £9.99 | £9.99 |
| Total | £34.24 | |||
| Cheapest per item across Screwfix | ||||
DIY vs Hiring a Tradesperson
£100.00 – £180.00
£100.00 – £180.00 per spur
£65.76 – £145.76
Shopping List (Mix & Match)
Cable & Wiring
- 1 × 10 m coil2.5 mm² Twin & Earth CableScrewfix£12.49
Fused Connection Unit
- 1 × 1 unitSwitched Fused Connection Unit (13 A)Screwfix£4.99
Back Box & Containment
- 1 × 1 boxSurface Pattress Box (1 Gang)Screwfix£1.39
- 2 × 2 m lengthMini Trunking (16 × 16 mm)Screwfix£5.38
Tools & Sundries
- 1 × 1 testerNon-Contact Voltage TesterScrewfix£9.99
Adding a spur from an existing ring main is one of the simplest electrical jobs a confident DIYer can tackle. A fused spur lets you power a new socket, a fixed appliance like an extractor fan, or a switched fused connection unit for a towel rail or kitchen appliance.
The key rule is one spur per socket on the ring — and never spur from a spur. You must also isolate the circuit and verify it's dead with a voltage tester before starting work. If you're comfortable with basic wiring, the job takes under an hour once you have everything to hand.
Assumptions
- Spur taken from an existing ring main double socket via a fused connection unit (FCU).
- Cable run of approximately 3 m between existing socket and new spur location.
- Surface-mounted mini trunking used for cable containment.
- Standard 13 A fused connection unit.
- Requires a competent DIYer; not notifiable under Part P if not in a special location.
What Affects the Cost
The main cost drivers are the length of the cable run and whether you choose standard white plastic accessories or a premium brushed chrome/steel finish. Cable is the single most expensive material — a 10 m coil covers most jobs, but longer runs will need more.
Mini trunking for surface-mount containment is cheap but adds up if the run is long. If you're chasing cable into the wall instead, you'll save on trunking but need access to an SDS drill and wall chaser.
A voltage tester is non-negotiable for safety. If you don't already own one, factor it in — it's a one-off purchase you'll reuse for any future electrical work.
Frequently Asked Questions
Do I need to notify Building Control to spur a socket?
In most cases, no. Under Part P of the Building Regulations (England & Wales), adding a spur from an existing circuit in a non-special location (i.e. not a bathroom or outdoor area) is minor work and does not require notification. If the spur is in a bathroom, kitchen near a sink, or outdoors, you should use a registered electrician.
Can I spur from any socket on the ring main?
You can only spur from a socket that is on the ring main itself — not from a socket that is already a spur. Each ring main socket can feed one spur only. If in doubt, use a socket tester with ring-main indication to check.
What size cable do I need for a 13 A spur?
2.5 mm² twin and earth cable (6242Y) is the correct size for a 13 A socket spur. This is the same cable used for the ring main itself.
How long does it take to spur a socket?
For a surface-mount spur using mini trunking, allow 45 minutes to 1.5 hours. Chasing cable into the wall will add more time depending on the wall type.