A:
Thank you for your recent inquiry. There is a red led labeled "site wiring fault" on the side of the UPS near the power cord. If this led is on, then it means one of the following issues has been detected:
1. Overloaded neutral wire (>5vdc measured between Neutral and Ground).
2. Reversed polarity (hot and neutral wires are reversed).
3. Missing ground wire. (Note: this also includes using a 3 prong to 2 prong adapter)
If this led is on, please remove the unit from service and have the wiring inspected.