Square D H366NR Fusible Safety Switch Disconnect

The Square D H366NR Fusible Safety Switch Disconnect is a heavy-duty, four-wire, 600 A, three-pole disconnect designed to safely isolate three-phase equipment up to 600 V. This NEMA 3R-rated enclosure is built to withstand outdoor and indoor installation, delivering rugged protection in demanding industrial settings. The unit accepts Class H fuses (and is compatible with Class K fuse provisions), providing fast fault clearing and reliable overcurrent protection for connected loads. With a 500 HP rating at 600 V, it can safely disconnect sizable motors and equipment without upsizing the switch, helping satisfy code requirements for motor disconnects in factory floors and processing plants. The 4-wire configuration includes three hot terminals plus a neutral, enabling proper line-to-line and line-to-neutral protection schemes and simplifying wiring for 3-phase systems. Designed for heavy-duty service, the H366NR is part of Square D's safety switch family, offering durable construction, straightforward installation, and proven performance in high-demand applications such as pumps, air compressors, conveyors, and other industrial machinery that require a dedicated disconnect for safe maintenance and protection.