Neutral grounding resistor
PGN-1000 series Littelfuse

The PGN-1000 Series Low-Resistance Grounding Systems are used to ground power systems by inserting a resistor between the system neutral and ground. This lowers the ground-fault current to a predetermined value. Properly sized resistance grounding systems solve two problems of ungrounded systems--transient overvoltages and difficulty locating ground faults. The PGN-1000 Series Resistance Grounding System includes all necessary components to convert or design a resistance grounded system. Low-Resistance Grounding also solves the solidly-grounded system problems of excessive ground-fault damage, and reduces ground-fault Arc-Flash Hazards. Properly sized resistors reduce ground-fault current to an acceptable level. Additional ground-fault relays (PGR-5701) can be installed on feeders to provide selective coordination as well as the ability to locate ground faults.

Applications
Low-Resistance Grounding is typically applied on
transformers and generators, and limits the ground-fault current to 25 A and above. Since ground-fault current is above 25 A, the faulted feeder must be de-energized. The reduced ground-fault current allows for an orderly shut-down procedure, typically within 10 seconds.

Features/Benefits
- Available from 480 V - 72 kV
- Available from 5 A - 800 A
- Can convert an existing ungrounded or a 3-wire solidly grounded system to a resistance grounded system. For more information on how to convert, see page 52.
- Resistance grounded relay or monitor (PGR-5330 or PGM-8325) is optional to provide ground-fault detection and resistor monitoring