Square D H321N - 30A, 240V, 3-Pole, Fusible, Disconnect Switch, NEMA 1

The Square D H321N 30A, 240V, 3-Pole Fusible Disconnect Switch (NEMA 1) blends dependable isolation with built-in overcurrent protection in a single, compact unit. Designed for demanding indoor environments, this switch delivers a clear on/off control and reliable fault protection for three-phase systems.

Why this fusible disconnect stands out

• Three-pole protection: Interrupts all three conductors simultaneously, ensuring safe shutdown of 3-phase motors and equipment.
• Integrated overcurrent protection: Fusible design provides immediate current interruption, reducing wiring and panel complexity by combining disconnection and protection in one device.
• Compact, maintainable form: A space-saving solution that fits tighter installations while remaining accessible for routine maintenance and fuse replacement.
• NEMA 1 indoor rating: Built for standard indoor electrical rooms and controlled environments, offering dependable protection where weather exposure isn’t a concern.

Ideal applications

Perfect for motor disconnects, panelboards, and branch circuit protection in commercial and light industrial settings. Use it to isolate large equipment during servicing, protect circuit runs of conveyors, compressors, pumps, and HVAC systems, or as a reliable main disconnect within a panel so maintenance crews can safely de-energize equipment without compromising protection.

Technical snapshot

• Model: H321N
• Amperage: 30A
• Voltage: 240V
• Poles: 3-Pole
• NEMA Rating: NEMA 1
• Fusible: Fusible disconnect switch

Installation & best practices

Install in indoor electrical rooms or panels where a compact, easy-to-service disconnect is advantageous. Pair this switch with appropriately rated fuses for your 240V, 3-phase load, and ensure wiring complies with local electrical codes. The H321N is designed to provide straightforward isolation for routine maintenance, reducing downtime and enhancing system reliability.

What makes it worth choosing

If you need a reliable, space-efficient solution that combines disconnect capability with protective fusing for 3-phase equipment, the Square D H321N delivers. It helps streamline panel design by consolidating functions into a single device, offers clear, lockable isolation, and supports practical maintenance workflows in busy facilities. For teams seeking dependable indoor protection and simplified circuit management, this fusible disconnect is a thoughtful, long-term fit.