FEEDER PROTECTION RELAYS
Feeder protection relays help protect circuits from overcurrent, ground faults, phase loss, overload and other detrimental conditions. Browse our feeder protection relays below.
MOTER PROTECTION RELAYS
A motor protection relay is designed to help protect motors from overloads, jams, phase loss or unbalance, heat, heavy start-ups or excessive operational cycles. Find the motor protection relay that meets your needs below.
Resistance Grounding/NGR Monitoring
Neutral grounding resistors work by limiting the fault current so it does not cause unwanted fault damage, but still allows the protective relays to work. Browse our NGR monitoring products.
Overview Resistance Grounding eliminates transient over voltages and single phase Arc-Flash hazards by reducing the ground-fault current to 5A, as well as the ability to locate the ground fault. Per IEEE Standard 141-1993, Arc-flash hazards are eliminated if the ground-fault current is reduced to 5 A or less. For systems 2.4 kV and higher, low-resistance grounding systems can be used. Properly sized resistance grounding systems solve two problems of ungrounded systems—transient over voltages and difficulty locating ground faults. These capabilities reduce unscheduled shutdowns due to electrical faults and equipment damage. The PGN Family of Resistance Grounding Systems includes all necessary components to convert or design a resistance- grounded system. Additional ground-fault relays, such as the PGR-4704, PGR-5300 or the PGM-8325 can be installed additional functions such as coordination as well as the ability to locate ground faults.
Ground faults occur when electricity travels an unintentional path between a power source and electrical ground. This can be dangerous to nearby personnel and could result in equipment damage. Littelfuse ground-fault protection relays offer the needed protection against ground faults. Find the ground-fault relay that meets your needs.
Overview The primary purpose of grounding electrical systems is to provide protection against electrical faults. However, this was not common practice until the 1970’s. Until then, most commercial and industrial systems were ungrounded. Although ungrounded systems do not cause significant damage during the first ground fault, the numerous disadvantages associated with ground faults resulted in a change to the grounding philosophy. There are other advantages for a grounded system, such as reduction of shock hazards and protection against lightning. Electrical faults can be divided into two categories: phase-to-phase faults and ground faults. Studies have shown that 98% of all electrical faults are ground faults (Source: Woodham, Jack, P.E. “ The Basics of Grounding Systems”. While fuses can protect against phase-to-phase faults, additional protection, such as protection relays, are typically required to protect against ground faults.