A circuit will not switch off, or will not switch on.
Learning Track · Module 7: Failure library · Step 48 of 101
| Symptom | Day burning on one circuit with a correct schedule, or a dark circuit with power at the cabinet. |
|---|---|
| Cause | Welded contacts from inrush current, a burnt coil, or loose terminals that overheat. |
| Check | Thermal image of the contactor. Check coil voltage when the controller switches. Look for pitted contacts. |
| Fix | Replace the contactor. Tighten all terminals to torque. |
| Prevent | Size contactors for LED inrush current, not only for running current. Many LED drivers draw a high inrush current at switch-on. |
Sources
- IEC 60364-6 Verification of low-voltage installations
- IEC 61643-11 Surge protective devices
- IEC 60598-2-3 Luminaires for road and street lighting
- Maker installation and maintenance instructions
Changes: 30 October 2026: First publication: guides for Europe, the Middle East, South Asia, and the USA; failure library; tender clause library; comparisons; tools; downloads. See the changelog. Found a mistake? Report it.