Ground Fault

What does E14 mean?

This fault indicates a ground fault detection between the inverter's output terminals and earth ground, typically during power-up tests. The inverter's protection system detects current leakage paths, tripping to prevent electric shock and damage to the motor or inverter.

• Motor cable insulation breakdown, causing a phase-to-ground short circuit in the cable (e.g., at conduit entry, cable tray).
• Motor winding insulation failure, resulting in a phase-to-ground short within the motor itself.
• Moisture ingress or conductive contamination (e.g., metal dust, coolant) at the motor terminal box or inverter output terminals.
• Damage to the motor cable shielding, allowing conductors to contact the grounded conduit or frame.
• Incorrect or missing earth ground connection for the motor frame or inverter chassis, leading to faulty detection.

Click steps to track your progress.

1. 1

   Disconnect all motor phases (U, V, W) from the inverter output terminals. Test insulation resistance between each output terminal and earth ground (PE) using a megohmmeter (insulation tester).

2. 2

   With motor cables disconnected from inverter, measure insulation resistance between each motor phase wire and the motor frame (PE) using a megohmmeter.

3. 3

   Visually inspect the motor terminal box and inverter output terminals for moisture, debris, or damaged insulation.

4. 4

   Verify the integrity and continuity of the earth ground (PE) connection from the inverter chassis to the main power panel.

5. 5

   If the fault clears with the motor disconnected, the ground fault is in the motor or motor cable; if it persists, the inverter has an internal ground fault.