Negative power or impossible power factor.
Learning Track · Module 7: Failure library · Step 56 of 101
| Symptom | Negative kW, power factor near zero, or energy on the wrong phase. |
|---|---|
| Cause | A current transformer fitted the wrong way, or CTs and voltage inputs on different phases. |
| Check | Compare each phase with a clamp meter. Check CT direction arrows and phase labels. |
| Fix | Turn or move the CT. Correct the wiring. Commission again. |
| Prevent | Follow the commissioning SOP before you accept the data. |
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.