Square D D321N - 30A, 240V, 3-Pole, General-Duty, Fusible, Safety Switch, NEMA 1

Square D D321N - 30A, 240V, 3-Pole, General-Duty, Fusible, Safety Switch, NEMA 1 is a rugged safety device designed for reliable on/off isolation and overcurrent protection in demanding industrial and commercial environments. Built to handle daily switching cycles, this fusible switch combines protection and control in a compact, maintainable package that’s ready to go in motor disconnects, panelboards, and branch circuits.

Designed for indoor, general-duty use, the NEMA 1 enclosure shields sensitive electrical components from dust and debris while keeping the power path clearly isolated when service or maintenance is required. The 3-pole configuration ensures balanced control across all phases, making it a straightforward choice for three-phase equipment and motors up to 30A at 240V.

Why choose the D321N for your installation

• Integrated protection and isolation: Safe, code-compliant motor disconnect with built-in fusible protection to guard against overcurrent events.
• Compact, maintainable design: The enclosure and fuse-accessible design simplify maintenance, fuse replacement, and routine inspections—reducing downtime.
• Indoor reliability: NEMA 1 enclosure delivers dependable protection in standard indoor environments such as equipment rooms, control panels, and factory floors.
• Three-phase readiness: Three poles provide synchronized control for 240V three-phase loads, supporting motors, conveyors, pumps, and HVAC equipment.

Key specifications at a glance

• Model: D321N
• Amperage: 30A
• Voltage: 240V
• Poles: 3-Pole
• NEMA Rating: NEMA 1
• Duty: General
• Fused: Fusible

Ideal use cases

• Motor disconnects for small to mid-size industrial equipment
• Panelboards requiring branch-circuit protection in indoor settings
• Indoor control cabinets, HVAC equipment, pumps, and conveyors that benefit from quick, reliable fusing

Practical tips for installation and operation

Plan for 30A, 240V three-phase service and ensure compatible fuse types are used with the D321N. Keep the enclosure accessible for safe operation and routine maintenance. Regularly check fuse integrity, tighten terminations to spec, and inspect the NEMA 1 seals to maintain dust protection. This switch is designed to simplify wiring in new builds or retrofits where a dependable, compact fusible disconnect is preferred over non-fused alternatives.