Protection Relays

pdf icon AF0100 Datasheet

pdf icon AF0100 Manual

pdf icon Improve Safety and Reliability with Instant Arc-Flash Detection - Brochure

pdf icon Littelfuse Arc-Flash Relay FAQ

pdf icon AF0100 Arc-Flash Relay Application Guide

pdf icon AF0100 Arc-Flash Relay Generator Application Guide


pdf icon Littelfuse Arc-Flash Relay Saves Plant from Catastrophic Damage - Case Study

pdf icon AF0500 Datasheet

The AF0500 is a microprocessor-based arc-flash relay that limits arc-fault damage by detecting the light from an arc flash and rapidly tripping the feeder breaker.

pdf icon AF0500 Manual

dwg AF0500 CAD Drawing

pdf icon AF0500 Arc-Flash Relay Application Guide

Document AF0500 Arc-Flash Relay Guideform Specifications

pdf icon Littelfuse Arc Flash Energy Reduction Workbook

AF0500 STP 3D Model

pdf icon PGR-8800 Datasheet

pdf icon PGR-8800 Manual

The PGR-8800 Arc-Flash Relay is a high-speed, arc-detection device for electrical power distribution systems.

dwg PGR-8800 CAD Drawing

pdf icon PGR-8800 Arc-Flash Relay Application Guide

pdf icon PGR-8800 Arc-Flash Relay Application Guide - Mandarin

Document PGR-8800 Arc-Flash Relay Guideform Specifications

PGR-8800 SKM Device Library Update

Update your SKM software to list the validated PGR-8800 when calculating your incident energy. Using this will save time by automatically determining your systems trip times, arc flash boundaries and required PPE. Please visit for instructions on how to install the SKM file.

PGR-8800 STP 3D Model

pdf icon CT Selection Guide

The Current Transformer (CT) Selection Guide provides assistance in selecting the appropriate CT for each protection relay.

pdf icon TN CT-03 Locating Phase Conductors in a Zero-CT Window

An ideal window-type current transformer responds only to the sum of the currents fl owing through its window...

pdf icon TN CT-04 Hammond CTs

pdf icon TN CT-06 CT Turns Ratio Modification

A window-type current transformer is also referred to as a core-balance or fl ux-balance transformer...

pdf icon TN CT-08 Ground-Fault Current Transformer Location

A ground fault on a grounded system can be detected using a current-sensitive ground-fault monitor...

pdf icon TN CT-09 Sensitive Ground-Fault Protection Using Split-Core CTs

A zero-sequence CT is optimized by using a symmetrical core and windings that are evenly spaced around the core. The symmetry allows the CT to operate in the presence of high load currents...

pdf icon TN CT-10 CT and PT Polarity Testing

Correct operation of MPS and FPS relays depends on accurate polarity. Markings on current transformers (CT) and potential transformers (PT) have been occasionally misapplied from the factory...

pdf icon TN CT-11 FPL Zero-Sequence Sensors with Littelfuse Relays

Littelfuse Protection Relay PGR 7200icon PGR 7200 Feeder Protection Relay

pdf icon TN FP-01 FPU-32 Replacement for Line Power Model 07-2000

pdf icon TN FP-02 Replacing FPU-16 with FPU-32

pdf icon TN FP-04 Testing the FPU-32 Feeder Protection System

pdf icon TN FP-06 FPU-32 Feeder Protection Unit Upgrade