Square D DU321RB 30A 3P 240V Safety Switch, NEMA 3R, Fusible, Non-Fusible | AmpState

The Square D DU321RB is a versatile safety switch designed to disconnect and isolate equipment right at the point of use. Built for reliable performance in demanding environments, this 30 A, 3-pole unit operates at 240 V and comes with NEMA 3R enclosure protection for dependable outdoor or recessed indoor service.

Key advantages of the DU321RB

• Three-pole, 240V protection— ensures secure shutdown of multi-phase equipment with straightforward conditioning for drive systems, pumps, conveyors, and HVAC com­ponents.
• NEMA 3R enclosure— weather-resistant design protects electrical contacts and wiring from the elements, dust, and incidental moisture, making it suitable for outdoor installations and harsh environments.
• Fusible or Non-Fusible configurations— choose the protection approach that best fits your system’s safety and maintenance plan (fusible for overcurrent protection options or non-fusible for direct isolation).
• Direct replacement mindset— sized and configured to align with original equipment manuals, helping you maintain BOM integrity during replacements or spares stocking.

Why this safety switch matters for your equipment

When you need a dependable disconnect at the point of use, the DU321RB delivers predictable performance and clear, hard-wired isolation. It’s ideal for rapid service outages, safe maintenance windows, and ensuring that downstream machinery stays protected during maintenance or fault conditions. By keeping a spare that matches the original part number, you reduce procurement risk and simplify maintenance ceremonies.

Specifications at a glance

• Manufacturer: Square D
• Part Number: DU321RB
• Amperage: 30 A
• Poles: 3
• Voltage: 240 V
• Enclosure rating: NEMA 3R
• Configurations: Fusible or Non-Fusible

Ideal for

Manufacturing lines, process equipment, pump stations, HVAC systems, and other machinery requiring a reliable disconnect with an easy-to-service, weather-resistant enclosure. It’s particularly well-suited for replacement projects where maintaining BOM alignment is important, or when stocking spares to minimize downtime.

How AmpState supports you

Available from AmpState, the DU321RB is part of a trusted lineup designed for clarity, compatibility, and long-term availability. If you’re unsure about fit or need help confirming compatibility with your existing equipment, send us a message and we’ll help verify the match against your part numbers and installation requirements.

Ready to secure your equipment with a proven Square D safety switch? Add the DU321RB to your cart and maintain reliable, code-compliant isolation for your critical systems.