Dépannage

Fixture flickers in cold weather

MR16 LED fixtures intermittently flicker, dim, or fail to start when temperatures drop below 5 °C.

Public: contractor15 min

Cold-weather flicker is almost always a voltage-drop or transformer-tap mismatch surfacing under load. Five-minute fix in 80% of cases.

Outils requis

1
Confirm the symptom under cold load
Wait until the run has been on for at least 30 minutes in below-zero conditions. Note which fixtures are flickering — first ones in the run, last ones, or all of them. This pattern alone narrows the cause.
2
Measure voltage at the transformer secondary
Probe the active tap. Acceptable: 12-15 V AC. Below 11.5 V means the transformer is undersized or overloaded; above 16 V means the tap is too high for the load.
⚠ Probe with the transformer energized but the load disconnected first to read open-circuit voltage, then probe under load.
3
Measure voltage at the failing fixture
Pull the lamp, probe the socket leads. Compare to transformer reading. A drop of more than 1.5 V from transformer to fixture means you're at or past the voltage-drop budget.
4
Run the voltage-drop calculator
Plug in your wire gauge, run length (transformer to that fixture), and total wattage on the run. If the calculator says > 10 % drop, either upsize the wire, split the run, or move to a higher transformer tap.
5
Verify lamp quality
If voltage is in spec but the fixture still flickers, swap in a known-good Luna Nova LN-1016 MR16 LED. Some third-party MR16 drivers don't tolerate the cold; ours are rated to −45 °C.