Often the electrical equipment in older pools had a leakage current that was greater than the 5 milliamps required for a Class A GFCI and this leakage current would cause nuisance tripping of the circuit. When using a Class B GFCI, the swimming pool lighting circuit must be disconnected before servicing or relamping the lighting fixture. There is a Class A GFCI that trips when a ground fault current exceeds 5 milliamps and there is a Class B GFCI that trips when a ground fault current exceeds 20 milliamps.Ī Class B GFCI with a 20 milliamp trip level is to be used only for protection of underwater swimming pool lighting fixtures installed before adoption of the 1965 National Electrical Code (NEC). The basic definition of a ground-fault circuit-interrupter (GFCI) is a general-use device whose function is to interrupt the electric circuit to a load within an established period of time. Three basic ground fault systems or leakage current protection devices are used in the electrical system: ground fault protection for personnel that are UL Listed in accordance with UL 943, immersion detection protection for appliances that are UL Listed in accordance with UL 1664, and ground fault protection for equipment that is UL Listed in accordance with UL 1053. See NEC 517.17)ġ0.The most important thing to understand about ground fault protection devices is that one type is to protect personnel and the other is to protect electrical equipment, the latter having different trip levels for different types of protection. Any system with Ground Fault Protection (except for Health Care Facilities. Resistance or impedance grounded systemsĩ. A 4,000A service could be split into 5 – 800A switchesħ. Service with six disconnects or less (NEC 230.71) where each disconnect is less than 1,000 amps. Any delta system (grounded or ungrounded)Ħ. Systems over 600-volts (high or medium voltage systems)ĥ. Any system with a disconnect less than 1000 ampsĢ. Specifically, Ground Fault Protection is NOT required for the following:ġ. These devices must also have regular maintenance including annual calibration.Īs mentioned earlier, there are some exceptions to the Ground Fault Protection rule. Improper wiring of the system, including accidental neutral return paths can easily negate the effectiveness of a Ground Fault Protection device. Also, the reliability of the GFP systems depends on many factors beyond the proper settings on the device. Ground Fault Protection systems are very sophisticated devices, often with many variable settings to “Dial-In” the specific requirements needed for your site. Does NOT provide protection from high-magnitude ground faults.Does NOT provide protection from 3-phase, phase-phase, or phase-neutral faults.Does NOT protect people and equipment from ground faults like a GFCI system (Ground Fault Circuit Interrupter).Does NOT protect people from shock hazards.There are a few exceptions to this rule, but first let me explain what Ground Fault Protection is NOT. NEC Article 230.95 does indeed require that all service disconnects over 1,000-amps must have Ground Fault Protection in addition to regular overcurrent protection systems. High-magnitude faults are stopped by traditional over current protection mechanisms. These low-magnitude faults are sensed by the breaker and current flow is stopped. Ground Fault Protection Circuit Breakers use special sensors to detect low-magnitude ground faults. The National Electrical Code (NEC) requires Ground Fault Protection for equipment in Articles 215.10, 230.95, 240.13 and 517.17. The NEC calls for use of Ground Fault Protection (GFP) type for circuit breakers for services over 1000A, does this include buildings or just equipment?
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