Lights flickering
One or more lights flicker — constantly, intermittently, or when other appliances run. Common with LEDs and dimmers, but can also signal a loose connection.
Safety first
Flicker from a loose connection can mean local heating — treat it seriously, not just as an annoyance. Isolate before investigating connections.
Isolate, lock out / tag out, and prove dead before working unless a live test is specifically required, authorised, and carried out under proper supervision. Always follow local regulations, your site procedures, and the equipment manufacturer's documentation.
Apprentice mode
Full walk-through — the why, what readings mean, mistakes & safety.
Likely causes
Ranked from most to least likely.
- 1
Incompatible LED / dimmer combination
Most likelyMany LEDs flicker on dimmers (or even some switches) they aren't matched to — a very common modern cause.
- 2
Loose connection in the lighting circuit
#2A loose terminal at a rose, switch, or junction causes intermittent flicker and can overheat.
- 3
Voltage dip when a large appliance starts
#3Lights dimming/flickering when a motor (aircon, pump) starts points at inrush/voltage drop.
- 4
Failing lamp / driver
#4An LED or driver near end of life can flicker before it fails.
- 5
Loose or high-resistance neutral
Least likelyA neutral problem can cause flicker across multiple lights — see lost-neutral fault-finding.
Reports are saved on this device to reflect what you actually find.
Testing sequence
Work through one test at a time. Expected reading and what each result means.
On the tools? Job Mode shows one test at a time with thumb-sized buttons — your place and readings carry straight over.
Enter Job ModeNote the pattern: one fitting or many? Constant, or only when something switches on?
A pattern pointing to lamp/dimmer vs wiring vs supply.
One fitting on a dimmer → suspect compatibility. Many/when appliances run → wiring/supply.
If random across the house, suspect a neutral or supply issue.
View all expected readings at once
Fault-finding flowchart
The same logic as a decision tree.
- 1start
Lights flickering
→ step 2 - 2decision
Is it one dimmed/LED fitting (vs many / when appliances run)?
Yes→ step 3No→ step 4 - 3decision
Are the LED and dimmer a compatible combination?
Yes→ step 5No→ step 6 - 4result
Many/with appliances — check connections, supply, and neutral.
- 5decision
Are the connections tight and cool?
Yes→ step 7No→ step 8 - 6result
Mismatch — fit compatible LED-rated lamps/dimmer.
- 7result
Investigate supply/neutral or a failing lamp/driver.
- 8result
Loose/hot connection — remake it.
Common mistakes apprentices make
- Assuming a wiring fault when it's an LED/dimmer compatibility issue.
- Ignoring flicker that coincides with a loose, heating connection.
- Not noticing flicker only happens when a big appliance starts.
- Overlooking a neutral problem when many lights flicker together.
When to stop & escalate
Flicker traced to a loose/heating connection or a neutral fault needs prompt repair by a licensed electrician (fire risk). Persistent flicker when large appliances start may indicate supply/voltage-drop issues to assess.
If you're past your competence, authorisation, or the safe limits of the job — stop and hand it on. There's no fault worth getting hurt over.
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Related faults
Dimmer buzzing or LEDs not dimming smoothly
A dimmer buzzes, the LEDs flicker/strobe at low levels, won't go very low, or some lamps glow when 'off' — typically an LED/dimmer compatibility issue.
Lost or high-resistance neutral
Strange symptoms across a circuit or installation — voltages going high and low on different loads, flickering, equipment damage — pointing to a lost or high-resistance neutral.
Loose connection overheating (discolouration / smell)
A terminal or connection is overheating — discoloured insulation, a burning smell, or heat you can feel — a common cause of nuisance faults and a real fire risk.
Learn the theory
How the gear and circuits behind this fault actually work.