Square D QMB-324 - 200A, 240V, 3-Pole Panelboard Switch / Switchboard Unit | AmpState

Meet the Square D QMB-324 fusible panelboard switch from Schneider Electric—a purpose-built, 200 A, 240 V, 3-pole unit designed to bring clear control and integrated protection to lighting and distribution panelboards. This compact module blends switching and fuse-based protection in one durable package, delivering reliable operation and coordinated protection when upstream devices are in play.

Why the QMB-324 stands out

• Integrated switching and protection in a single fusible panelboard unit. The QMB-324 unifies the disconnect function with fuse-based protection, simplifying installation and enhancing system resilience.
• Panel-level fault interruption for precise coordination with upstream protection devices, limiting fault impact to the affected feeder and helping protect downstream circuitry.
• Code-compliant, centralized disconnect ideal for maintenance access without compromising circuit reliability. A clear, local point of control makes servicing safer and faster.
• Wiring simplification and enclosure efficiency—fewer components and neater layouts mean less clutter inside the panel and easier future upgrades.
• Designed for demanding lighting and distribution needs in commercial offices, retail spaces, schools, and light industrial environments where coordinated protection matters.

How it works and when to use it

The QMB-324 is purpose-built to be paired with appropriate upstream protection and a compatible fuse class. In the event of a fault, the unit interrupts at the panel level, providing a well-defined maintenance disconnect and ensuring downstream feeders stay protected and isolated as needed. This makes it an excellent choice when you need a centralized, protective disconnect that doesn’t sacrifice reliability or accessibility.

Ideal use cases

• New panel installations requiring a dedicated fusible disconnect for critical lighting and distribution circuits.
• Panelboard retrofits where coordination between upstream protection and downstream feeders is essential for safe fault isolation.
• Projects seeking a single, clearly identified disconnect point to streamline maintenance without adding complexity.

Specifications at a glance

• Amperage: 200 A
• Voltage: 240 V
• Poles: 3
• Manufacturer: Square D / Schneider Electric
• Part Number: QMB-324
• Series: QMB

Practical installation and maintenance tips

• Confirm compatibility: ensure upstream protection devices and the selected fuse class align with the QMB-324 for optimal performance and safety.
• Check enclosure fit: verify physical compatibility with your panelboard enclosure before mounting and wiring.
• Follow local codes: adhere to applicable electrical codes for mounting, wiring, and accessibility of the disconnect point.
• Keep a small fuse stock: maintain a minimal supply of recommended fuse links to reduce downtime and ensure rapid fault isolation when needed.
• Periodic checks: inspect the switching mechanism during routine panel maintenance to confirm smooth operation and reliable interruption when required.

Enhance your lighting and distribution paneling with the Square D QMB-324—a robust, dependable fusible panelboard switch that delivers clear, controlled switching and protective coordination in one proven package.