POWER LINE NOISE ISSUES WITH GROUND FAULT PROTECTION EQUIPMENT
Due to the high sensitivity of ground-fault-current detection circuits, it is possible that excessive line noise on the power source wiring can cause an alarm. This can occur in the form of a ground-fault alarm, a stuck-relay alarm, or a ground-fault circuit alarm.
This type of alarm can be caused by switching high-power loads, inductive loads, or any excessive arcing during operation of a contactor that is on the same circuit branch. It may also be caused by extreme levels of RFI (radio-frequency interference) in the area.
1. USE A SEPARATE CIRCUIT FOR THE HEAT CONTROL
We recommend providing a separate circuit for the heat control, which is not shared with other equipment. In particular, any equipment that is electrically noisy needs to be on a different circuit branch and installed a safe distance away.
2. ADJUST THE GROUND FAULT THRESHOLD
In some situations, the ground fault threshold can be increased, and this will improve the noise immunity. On the GPT 130 and GPT 230, the ground-fault alarm current threshold can be adjusted from 1 mA to 300 mA, and the default setting is 30 mA. A higher setting will be more tolerant of electrical noise on the power line.