Square D QMB366W - 600A, 600V, 3-Pole Panelboard Switch / Switchboard Unit | AmpState

Meet the Square D QMB366W from AmpState—a robust 3-pole fusible panelboard switch engineered for dependable load switching in lighting and distribution panelboards. Built on Schneider Electric’s trusted QMB series, this unit delivers controlled isolation and coordinated protection when paired with the right upstream devices and fuse class, making it a reliable cornerstone for commercial and light-industrial electrical installations.

Why the QMB366W stands out

• High-current, three-phase performance: With 600 A capacity at 600 V across three poles, it delivers consistent switching and protection across all phases, helping minimize voltage imbalances in larger panelboard layouts.
• Space-efficient fusible disconnect: Combines switching and fused protection in a single, compact unit tailored for panelboard environments, simplifying installation and maintenance workflows.
• Ecosystem compatibility: Part of the Square D QMB family, ensuring seamless parts availability, accessories, and service within Schneider Electric’s ecosystem for ongoing reliability.
• Coordinated protection when upstream is matched: Designed to work with appropriate upstream protection and fuse class, delivering proper overcurrent protection coordination and reducing nuisance trips to downstream equipment.

What this means in practical terms

The QMB366W is ideal when you need a dependable fusible disconnect within lighting and distribution panelboards. It’s especially valuable in mid-to-large commercial installations where a solid, three-pole disconnect with fused protection is required and where staying within the Schneider Electric family simplifies maintenance and spare parts management.

Key use cases

• Lighting panelboards in office, retail, or educational facilities that benefit from a controlled maintenance disconnect with fused protection.
• Distribution panelboards in mid-to-large commercial spaces needing robust 3-pole isolation and coordinated upstream protection.
• Panel upgrades or replacements within Schneider Electric ecosystems to preserve compatibility with existing breakers, fuses, and spare parts.

Compatibility and installation tips

• Pair the QMB366W with the appropriate upstream protection and fuse class to achieve the intended overcurrent protection coordination. This pairing is essential to prevent nuisance trips and to protect downstream equipment.
• Consult the QMB series documentation to confirm mounting and enclosure compatibility within your panelboard assembly, ensuring a clean, code-compliant installation.
• Consider stock planning for Schneider Electric components to maintain serviceability and parts availability across facilities.

Specs at a glance

• Amperage: 600 A
• Voltage: 600 V
• Poles: 3
• Series: QMB (Square D / Schneider Electric)
• Part number: QMB366W
• Function: Fusible panelboard switch for reliable load switching and overcurrent protection when used with appropriate upstream protection and fuse class

Designed with panel systems in mind, the QMB366W helps you consolidate switching and protection into a single, space-conscious device. By staying aligned with the Square D QMB family, it simplifies maintenance planning, spares stocking, and service continuity across facilities that rely on Schneider Electric components.

Who benefits most

• Electrical engineers and facility managers overseeing commercial or light-industrial buildings that require reliable, code-compliant fusible disconnects in panelboards.
• technicians performing panel upgrades or replacements who want seamless integration with existing Schneider Electric breakers, fuses, and spare parts.

In short, the QMB366W is not just a switch—it’s a thoughtfully engineered solution that aligns switching, protection, and system coordination in a single, dependable panelboard unit. When you need a durable, three-pole fusible disconnect that’s ready to integrate into a Schneider Electric ecosystem, the QMB366W delivers clarity, reliability, and long-term serviceability.