Square D QO345 45A 3P 240V Circuit Breaker, QO, Plug-On | AmpState

Meet the Square D QO345 — a purpose-built 3-pole, 45A, 240V plug-on circuit breaker designed to protect 3‑phase circuits in panelboards, load centers, and electrical distribution systems. Built for reliability in retrofit projects and maintenance planning, this unit helps keep critical equipment safe with consistent part numbers that simplify inventory and service calls.

Why the QO345 stands out

• 3-pole, 240V protection tailored for 3‑phase loads such as motors, compressors, and other equipment that require simultaneous interruption across all phases.
• QO Plug-On design enables fast, clean installations and straightforward swaps in compatible Square D panelboards and load centers, reducing downtime during upgrades or repairs.
• Exact part number match with QO345 ensures you can preserve existing maintenance schedules and spare-part inventories without reconfiguring panel labeling or documentation.
• Square D reliability backed by decades of field-tested performance in commercial and industrial electrical distributions.

Ideal use cases

• Retrofit work where maintaining a specific part number is essential for compatibility with existing panels and service records.
• Maintenance planning for facilities with 3‑phase equipment that operates at 240V, such as HVAC drives, conveyor motors, and large pumps.
• Spare-part strategy for field crews: keeping a single, familiar breaker type on hand to minimize stocking complexity and ensure fast replacements.

Compatibility & installation considerations

The QO345 is designed for Square D QO-series panelboards and load centers that accept 3-pole, 240V plug-on breakers. Before installation, confirm that your panel supports QO plug-on devices and that the bus/slot configuration aligns with a 3P, 240V, 45A device. Following the panel manufacturer's guidelines for torque, wiring, and labeling will help ensure reliable operation and safe, code-compliant performance.

What you get with AmpState

Available directly from AmpState, the QO345 provides a dependable solution for ongoing service and upgrades. If you’re unsure about fit or compatibility with a specific panel, send us a message and we’ll help confirm the match to minimize downtime and avoid mismatches in the field.

Keep your electrical distribution protected with a trusted Square D QO345—designed for precise 3‑phase protection, swift replacement, and seamless integration into existing QO family installations.