Skill: Fused Spur, Wire in a FCU
Skill level: 3
Wiring
Learning Objective:
Learn how to safely wire in a fused spur (also called an FCU) to power gate equipment or accessories, complying with electrical safety standards and best practices.
1. Overview
A fused spur (FCU) provides a local isolation and protection point for gate systems.
Protects equipment with the correct rated fuse (typically 3A or 5A).
Provides safe isolation for engineers and end users.
Ensures compliance with electrical safety standards.
⚠️ Never assume an isolator elsewhere is sufficient — every gate should have a dedicated FCU.
⚠️ Using the wrong fuse can cause fire or serious damage.
2. Tools and Materials Required
Fused spur unit (switched or unswitched as specified)
3-core 1.5mm² or 2.5mm² cable (T&E or SWA depending on site)
3A or 5A BS1362 fuse (correct rating for gate controls)
20mm back box or pattress (surface mount)
Insulated screwdriver set
Wire strippers and cutters
Voltage tester + proving unit
Masonry drill, rawl plugs, screws
Grommets or stuffing glands
Labels
Silicone sealant (weatherproofing if external)3. Before You Start
Isolate the circuit at the consumer unit.
Prove dead using two-pole tester + proving unit.
Label isolation point if others are on-site.
Wear PPE: gloves, eye protection.
Check for bonding and avoid mixing circuits.
3. Before You Start
Isolate the circuit at the consumer unit.
Prove dead using two-pole tester + proving unit.
Label isolation point if others are on-site.
Wear PPE: gloves, eye protection.
Check for bonding and avoid mixing circuits.
4. Procedure
4.A Mount the Back Box
Select visible, accessible location near control panel.
Avoid plasterboard joints/fragile surfaces.
Drill, fix securely, and fit grommets/glands for cable entry.
4.B Prepare Cable
Strip outer sheath carefully.
Strip cores: Brown (Live), Blue (Neutral), Green/Yellow sleeved Earth.
Leave enough length to reach terminals neatly.
4.C Connect Incoming Supply
Brown (Live) → L IN.
Blue (Neutral) → N IN.
Earth → Earth terminal.
4.D Connect Load (Gate System)
Brown → L OUT.
Blue → N OUT.
Earth → Earth terminal (double if required).
📌 Check earth continuity when using SWA/T&E.
4.E Insert Fuse
Fit BS1362 fuse (3A or 5A as required).
Never substitute or guess rating.
4.F Close Unit & Label
Tug-test wires for tightness.
Ensure no bare copper visible.
Close cover securely.
Label clearly: “Gate Power – Isolate Here.”
4.G Test Supply
Restore power at consumer unit.
Confirm 230V at FCU output using tester.
Power up gate equipment and confirm operation.
4.H Final Tasks
Photograph wiring for Clik/AppSheet.
Log fuse size and FCU location.
Leave clear labels for customer and engineers.
5. Best Practices
✅ Always prove dead before wiring.
✅ Use correct fuse rating — typically 3A or 5A.
✅ Label unit clearly for isolation.
✅ Secure box with correct fixings and grommets.
✅ Record details in Clik/AppSheet.
✅ Test output voltage before handover.
6. Common Mistakes to Avoid
Table:
Wrong fuse rating → Fire or equipment damage.
Loose earth → Safety failure.
No grommet → Cable damage/water ingress.
No test before use → Risk of shock or injury.
Incorrect termination → Poor contact/overheating.
7. Safety Information
Relevant SSOW References:
SSOW-01: Electrical Isolation & Lock-off
SSOW-04: Working With Mains Voltage (230V AC)
SSOW-05: Safe Use of Multimeters
SSOW-09: Manual Handling (boxes, drills, fixings)
SSOW-11: PPE (gloves, boots, eye protection)
⚠️ Always isolate at consumer unit and prove dead before wiring.
⚠️ Only fit BS1362 fuses at the correct rating.
⚠️ Label FCU clearly to prevent accidental energisation.