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How to check GND?

Last modified by Theodore Xu on 2026/01/15 16:56

A reliable grounding connection can be verified through a three-step procedure: visual inspection, resistance measurement, and operational verification.

1. Visual Inspection
Check the connection between the inverter's ground terminal (PE) and the grounding busbar/wire. Ensure the terminal is free from looseness, oxidation, or corrosion, and confirm that the entire grounding path is intact without breaks.

2. Resistance Measurement (Power OFF)
Disconnect all power to the inverter. Use a multimeter in resistance mode (Ω). Connect one probe to the inverter’s PE terminal and the other to a verified grounding point (e.g., the building's grounding busbar or a dedicated metal earth rod). A proper ground connection should measure ≤4Ω. A reading of infinity (OL) indicates a broken ground. A higher-than-normal reading suggests issues like corrosion or loose connections in the grounding system.

3. Operational Verification (Power ON)
With the inverter powered and running, measure the voltage between the inverter chassis and the ground point using a voltage tester or multimeter. Under normal conditions, this voltage should be close to 0V. If the chassis is live or a significant voltage is detected, it indicates poor grounding.

The grounding point must be a compliant common grounding network or an independent earth electrode. Never use the neutral line as a ground path.