A ground fault protection system for a service is protective equipment that detects ground faults, unintended current flowing to ground, on larger electrical services and opens the circuit to interrupt them, preventing the equipment damage and fire that a sustained ground fault can cause. This is sometimes called ground fault protection of equipment (GFPE), and code generally requires it on certain large commercial services. It differs from the personnel-protecting GFCI used at outlets. Understanding what it does helps explain an important protection on large commercial electrical systems.

Here is what a ground fault protection system for a service is.

Ground fault protection of equipment is governed by code requirements that depend on service size and voltage, so its application is determined by qualified electricians or engineers following the applicable code.

What it protects against

A ground fault occurs when current flows unintentionally to ground, for example through a fault in equipment or wiring. On a large electrical service, a ground fault can involve significant current and, if not interrupted, can cause severe equipment damage, arcing, and fire. Ground fault protection for the service detects these faults and opens the circuit to stop them before they cause that damage. Its job is protecting the equipment and system from destructive ground faults.

How it works

A service ground fault protection system senses the current and detects when current is leaking to ground, indicating a ground fault, by measuring the imbalance that a ground fault creates. When it detects a ground fault above its setting, it signals the service disconnect or breaker to open, cutting power and interrupting the fault. This happens quickly to limit the damage. The system is integrated with the service’s main overcurrent protection.

It is required on certain large services

Code generally requires ground fault protection of equipment on certain large commercial services, based on the service size and voltage (for example, larger services at certain voltage levels). The specific thresholds are defined by code. The reason is that large services can deliver enough current in a ground fault to cause serious damage, so this protection is mandated where that risk is significant. Whether a given service requires it is determined by qualified professionals applying the code.

How it differs from GFCI

It is important not to confuse service ground fault protection (GFPE) with the GFCI protection used at outlets. They both respond to ground faults, but:

• GFCI protects people from shock, tripping at a very low current level, used at outlets in bathrooms, kitchens, outdoors, and similar locations
• GFPE (service ground fault protection) protects equipment and the system from damage, operating at much higher current levels on large services

So GFCI is about personnel safety at the point of use, while service ground fault protection is about protecting large equipment and systems from destructive faults.

Designed and maintained by professionals

Because ground fault protection for a service is part of the design of a large electrical system, governed by code and integrated with the service equipment, it is specified, installed, and maintained by qualified electricians or engineers. They determine whether it is required, set it up correctly, and ensure it is tested and maintained so it functions when needed. This is specialized work befitting the large systems it protects.

A ground fault protection system for a service (ground fault protection of equipment, GFPE) detects ground faults on larger electrical services and opens the circuit to interrupt them, preventing the severe equipment damage and fire a sustained ground fault can cause. Code generally requires it on certain large commercial services based on size and voltage, and it differs from the personnel-protecting GFCI used at outlets. It is specified, installed, and maintained by qualified professionals.

Stella Electric supports commercial service protection and electrical systems for businesses across the Baltimore area and throughout Maryland, with flat-rate pricing and no overtime charges. If your facility has large service protection needs, we can help you take the right steps. Financing is available on qualifying projects.