Reference · Testing & Inspection
Ground Fault
An unintended connection between a circuit conductor and earth ground, usually from damaged insulation, moisture or a pinched cable. Panels monitor for it and show a trouble; two ground faults on opposite conductors become a short.
NFPA 72: 10.6.9 (ground-fault detection), 12.6
Section numbers vary by edition — confirm in the edition your AHJ has adopted.
Read more in these guides
Ground Faults on Fire Alarm Circuits: How to Find and Clear ThemGround faults are the most common — and most maddening — fire alarm trouble. Here's a calm, methodical way to find and clear one.Commercial Fire Alarm Troubleshooting: Opens, Shorts & Ground FaultsTrouble signals on a commercial system almost always come down to opens, shorts, or ground faults. Here's a repeatable way to isolate them without guesswork.