Spurs and isolators

What this usually means

This guide is for fused spurs, switched fused connection units (often called FCUs) and local isolators. In plain English, these are the small control points that let a fixed appliance be switched off nearby and, in some cases, fused locally.

Typical solutions

• Replace a faulty fused spur, FCU or appliance isolator like-for-like where the surrounding point is otherwise sound.
• Check the supply, local fuse arrangement and connections before assuming the boiler, fan or hood itself has failed.
• Confirm whether this still looks like a straightforward accessory job or whether it needs repair or fault-finding instead.

Basic information

• A fused spur is not the same as an ordinary switch plate; the accessory type and fuse rating need to suit what it feeds.
• Isolators are common around boilers, extractor fans, cooker hoods and other fixed appliances.
• A clear photo of the point and a note saying what it controls usually makes the first answer much easier.

What to send first

• Your postcode and a clear photo of the spur, FCU or isolator.
• A short note on what it controls, such as a boiler, fan, hood or appliance.
• Say if the point is hot, cracked, buzzing, smells burnt, trips, or seems dead.

What can change the scope

• Heat damage, a cramped or damaged back box, or signs of poor previous work can move this beyond a simple replacement.
• Bathroom or utility fan isolators may need extra care around access, location and the right part.
• If the fault sits beyond the accessory itself, the next step may change from a quick swap to repair or diagnosis.