Ground Protection

What does E14. mean?

This fault is detected when a ground fault occurs between the inverter output unit and the motor, typically at power-on. The inverter's ground protection function activates to prevent electrical damage and ensure safety. This indicates an insulation breakdown or improper wiring in the motor circuit.

• Short circuit from one or more motor output phases (U, V, W) to ground in the motor cable.
• Motor winding insulation breakdown to the motor frame (ground).
• Water, oil, or metallic dust contamination in the motor junction box or cable conduit, creating a conductive path to ground.
• Internal inverter output stage (IGBT) short circuit to the inverter's chassis ground.
• Damaged or improperly installed motor cable glands failing to maintain insulation.

Click steps to track your progress.

1. 1

   Disconnect the motor from the inverter output terminals (U, V, W) and re-apply power to the inverter; if the fault clears, the issue is with the motor or cable.

2. 2

   Perform an insulation resistance test (megohmmeter) between each motor phase (U, V, W) and the motor frame ground; resistance should be >1 MOhm.

3. 3

   Visually inspect the motor cables for any physical damage, chafing, cuts, or signs of moisture/oil ingress.

4. 4

   Inspect the motor junction box and internal windings for contamination, moisture, or carbon tracking.

5. 5

   If the fault persists with no motor connected, measure resistance from inverter output terminals (U, V, W) to inverter chassis ground (FG) with power off; check for near-zero resistance.