How to Fix an RCD Tripping from a Lighting Circuit (Leeds Homeowners Guide)

If your RCD keeps tripping and you suspect the lighting circuit, use this safe, step-by-step checklist. If anything looks unsafe, contact a qualified electrician in Leeds.

Safety First

If there’s a burning smell, heat, buzzing, or water near lights/ceiling, stop and call an emergency electrician in Leeds.

Do not remove fixed wiring or open the consumer unit beyond the flap.

1) What You’ll Need

• Torch
• Step ladder
• Spare lamps/bulbs
• Notepad/phone to track steps

2) Step-by-Step: Resetting an RCD Caused by Lighting

1. Identify the tripped device
2. At the consumer unit (fuse board), note which RCD is down. Identify lighting MCB(s) or RCBOs under that RCD (often labelled “Lights Up/Down”).
3. Switch OFF lighting MCBs
4. Turn OFF all lighting MCBs protected by the tripped RCD.
5. Reset the RCD
6. With lighting MCBs OFF, reset the RCD to ON.
7. If it won’t reset, the fault is on another circuit or the RCD itself. Call a Leeds electrician.
8. Turn ON lighting MCBs one by one
9. Switch on one lighting MCB at a time.
10. If turning one ON trips the RCD, you’ve identified the problem lighting circuit (e.g., downstairs lights).
11. Isolate the faulty point on that lighting circuit
12. Turn the faulty lighting MCB OFF again.

On that floor/area, do the following before re-testing:

• Switch all wall switches to OFF.
• Remove or unplug any plug-in transformers (e.g., lamps on fused spurs).
• Inspect for water ingress around bathrooms, kitchens, outdoor lights, lofts, and porches.
• Check each light fitting, starting with common culprits
• Bathroom/shower lights and extractor fans (steam ingress)
• Outdoor/security lights (water in PIR/fitting)
• Loft lights (rodent damage, disturbed cables)
• Downlights (overheating, damaged lampholders/transformers)
• Decorative pendants with metal shades (pinched flex)
• Remove bulbs and suspect accessories

With the lighting MCB still OFF:

• Remove bulbs/lamps from fittings on the suspect circuit.
• For low-voltage downlights, disconnect individual transformers if accessible.
• Unplug or isolate extractor fan at its isolator (often a 3-pole switch outside the bathroom).
• Turn the lighting MCB ON, then reset the RCD. If it now holds, reintroduce items one by one.
• Reintroduce lights one at a time
• Fit a known-good bulb into a single fitting, switch it ON, wait 10–20 seconds.
• Continue, one fitting at a time. When the RCD trips, the last fitting or connected device is likely faulty.

3) Specific checks per fitting type

• Downlights: Look for browned lampholders, brittle cabling, loose push-fit connectors, or insulation touching hot lamps.
• Outdoor/PIR lights: Check cracked seals, full water bowls inside fittings, corroded terminals.
• Extractor fans: Moisture-damaged motors or timer modules often leak to earth; isolate and retry.
• Smart switches/dimmers: Faulty modules or incorrect wiring can trip RCDs; revert to OFF/isolated and retest.

4) Restore safe operation or leave faulty item isolated

• Leave the faulty light/fan isolated (lamp removed, switch taped OFF, or fan isolator OFF).
• Label it “Do not use”. Reset RCD and confirm other lights work normally.

5) When to call an electrician

• RCD trips with lighting MCBs OFF
• Trips continue with all bulbs removed and fans isolated
• Signs of water ingress, heat damage, or tripped repeatedly after rain
• Old wiring (rubber or cloth), missing earths, or metal fittings without earth
• You’re unsure about circuit labeling or access

6) Preventing Future Lighting Trips

• Use IP-rated fittings in bathrooms and outdoors.
• Replace failed PIR/security lights with quality, sealed LED units.
• Keep loft cables clear of insulation and junctions in suitable boxes.
• Avoid mixing many electronic drivers on one circuit; use quality dimmers matched to LED loads.
• Book an EICR every 5 years (or on property purchase).
• Consider RCBO upgrades to isolate faults to a single circuit.

7) Need a Lighting Electrician in Leeds?

Duravault Electrical can help with:

• Lighting fault finding and RCD tripping diagnostics
• Bathroom and outdoor lighting repairs/replacements
• Extractor fan isolations and replacements
• Consumer unit and RCBO upgrades
• EICR inspections

Service areas: Leeds city centre, Headingley, Hyde Park, Chapel Allerton, Roundhay, Moortown, Horsforth, Yeadon, Guiseley, Pudsey, Farsley, Calverley, Bramley, Armley, Kirkstall, Morley, Rothwell, Garforth, Crossgates, Seacroft, Wetherby, Otley, Wakefield, Harrogate, York.

For fast help with lighting faults in Leeds, book a same-day visit from a local electrician.