Adding a Spur Socket

A spur is a branch cable taken from the ring final circuit to feed one extra socket. It's the simplest way to add a socket without rewiring the whole ring.

What a Spur Looks Like

The Rules

• One spur per socket on the ring. You can only take a spur from a socket that does not already have a spur.
• One socket per spur (a twin/double socket counts as one connection point for this purpose). Do not use a non-fused spur to feed a multi-gang extension board.
• Spur cable must be 2.5mm² T&E — same as the ring.
• The spur cannot loop back to form another ring — it must be a dead end.
• RCD protection: If the spur cable runs inside a wall, the circuit must be protected by a 30mA RCD or RCBO. Most modern consumer units already provide this — if yours doesn't, get an electrician to upgrade the circuit before you run cable in the wall.

How to Identify a Ring Socket

You need to check before taking a spur. At a ring socket, there should be two cables entering (ring in and ring out). At a spur socket, there's only one.

Important: Always isolate the circuit at the consumer unit before opening any socket. Test with a non-contact voltage tester before touching any conductors.

Non-Fused vs Fused Spurs

• Non-fused spur — connects directly to the ring via a socket's terminals. Protected by the 32A ring MCB.
• Fused spur — via a Fused Connection Unit (FCU) with a lower-rated fuse (e.g. 13A or 5A). Useful for permanently connected appliances.