groundfault

A ground fault is an unintended electrical fault in which current escapes from its intended path, typically from a live conductor to a grounded object or the earth. This abnormal current flow can occur when insulation is damaged, a conductor contacts a grounded surface, moisture is present, or equipment faults create a leakage path. Ground faults create shock hazards and can damage equipment or start electrical fires if the fault current is sufficient or the fault persists.

In normal operation, the current returning through the neutral conductor matches the current leaving on the hot conductor. A ground fault creates an imbalance, allowing current to flow through an alternate path such as a person, water, or grounded metal surfaces. The severity depends on the fault location, circuit impedance, and the amount of leakage current.

Protection against ground faults relies on specialized devices. Ground-fault circuit interrupters (GFCIs) or residual current devices (RCDs) monitor the current in the hot and neutral and trip when an imbalance is detected, typically at a threshold of a few milliamperes (commonly around 4–6 mA for GFCIs in many regions). These devices are widely used in wet or damp locations, outdoors, kitchens, and bathrooms. In industrial settings, additional protection may be provided by equipment-grounding systems and RCCB-type devices; arc-fault protection may also be used with GFCIs for broader safety.

Regular testing and maintenance are important. GFCIs include test buttons to verify operation, and labels indicate areas of protection. Proper grounding, intact insulation, and adherence to local electrical codes help minimize ground faults and their hazards.