Fused Connection Units (FCUs)

A Fused Connection Unit (FCU) is a switched or unswitched outlet that provides a fused, permanently wired connection to an appliance. Unlike a plug-in socket, the FCU incorporates a cartridge fuse (typically 3A or 5A) for protection.

When to Use an FCU

FCUExtractor fanFCUFridgeFCUTowel railFCUBroadband

FCUs are ideal for:

  • Appliances that run continuously (fridges, extractor fans)
  • Equipment that must not be accidentally unplugged
  • Low-current devices where you want a lower fuse value than 13A

Switched vs Unswitched

Switched FCU — has an on/off rocker. You can de-energise the appliance without unplugging.

Unswitched FCU — no switch. Typically used where the appliance has its own power control.

Fuse Ratings

The fuse inside the FCU should match the appliance:

| Fuse | Typical use | |------|-------------| | 3A | TV, lamp, broadband router | | 5A | Extractor fan | | 13A | High-power appliances |

Wiring

An FCU is wired like a socket — connected to the ring main. The load terminals feed the appliance cable directly. The FCU fuse protects the appliance cable, not the ring cable.

Always fit an FCU rated for at least the appliance's running current, but not higher than the ring MCB rating (32A).