Square D QMB365W - 400A, 600V, 3-Pole Panelboard Switch / Switchboard Unit | AmpState

The Square D QMB365W is a rugged fusible panelboard switch engineered for dependable load switching and overcurrent protection within lighting and distribution panelboards. With a robust 400 A rating and 600 V capability, this 3-pole unit is built to tackle demanding three‑phase applications while delivering clear isolation and coordinated protection when paired with the right upstream protection and fuse class.

Why the QMB365W stands out

• Three‑pole design for three‑phase systems: Efficiently handles balanced and unbalanced loads across standard 3‑phase distribution networks, ensuring steady performance in complex facilities.
• 400 A, 600 V capability: Ready for heavy lighting and power distribution tasks common in mid‑to‑large commercial buildings and industrial spaces.
• Fusible panelboard protection: Combines reliable load switching with overcurrent protection when used with appropriate upstream protection and fuse class, helping to simplify safety and code compliance.
• Proven compatibility: Part of the trusted Square D QMB series, ensuring seamless integration with other QMB components and standard panelboard configurations.
• Clear isolation and serviceability: Facilitates maintenance with visible, positive disconnects and predictable protective coordination in active electrical rooms.

Ideal use cases

• Lighting and distribution panelboards in mid‑to‑large commercial facilities where reliable isolation and protection are required.
• Retrofits or new installations that demand a recognized fusible switch within a 3‑phase 600 V distribution network.
• Electrical rooms and service panels that rely on coordinated upstream protection to meet safety and code expectations.

Installation, compatibility, and safety considerations

• Ensure upstream protection and fuse class are selected to match the 400 A, 600 V rating for safe, compliant operation.
• Designed for panelboard installation in lighting and distribution applications—verify enclosure space and mounting provisions align with your panel design.
• Installation should be performed by qualified electrical personnel in accordance with applicable codes and manufacturer guidelines.

Technical snapshot

• Amperage: 400 A
• Voltage: 600 V
• Poles: 3
• Manufacturer: Schneider Electric / Square D
• Series: QMB
• Part Number: QMB365W

For professionals seeking a dependable, code‑aligned fusible switch within panelboards, the Square D QMB365W delivers clear isolation, coordinated protection, and enduring reliability. It’s a pragmatic choice for managing heavy‑load distribution while prioritizing safety, maintainability, and system integrity.