Schneider Electric QMB-323-T31 Fusible Switch

Schneider Electric’s Square D QMB-323-T31 Fusible Switch is a three-pole, 100 A fusible disconnect designed for use with QMB fusible panelboards and D2-style switchgear. Rated for 240 VAC, it accepts Class R, H, or K fuses and delivers a 200 kA short‑circuit current rating at 240 V, providing robust fault protection for feeders and motor circuits. This dual/dual‑style unit supports two circuits, with documented variants in the QMB323 family such as QMB323TD (3P, 100 A, 240 VAC, 15 hp at 240 V, about 4.5 in deep) and QMB323TW (Twin Branch, 3P, 100 A, 240 VAC, about 6 in high), as described in Schneider Electric’s QMB panelboard literature. The enclosure is listed to NEMA 1 for indoor applications and is intended for use with QMB D2 panelboards and switchgear distribution systems. Note that Schneider Electric lists QMB323 series fusible switches as discontinued as of May 31, 2024, making the QMB-323-T31 a legacy option best suited for retrofit work in existing installations needing a 3-pole, 100 A disconnect with 240 VAC service and Class R fuse compatibility. Typical applications include safe isolation of feeders and motor circuits in light commercial and industrial environments where reliable switchgear access and clear fuse protection are required.