Square D | 999340 | Circuit Breaker | 40A | 3-Pole | 600V

Square D 999340 Circuit Breaker delivers dependable overload protection for three‑phase systems, packaged as a compact, retrofit‑friendly solution. Sized at 40 amps with a 3‑pole design and a 600-volt rating, it’s built for maintenance, retrofit, and replacement projects where exact specifications matter and compatibility is paramount.

• Amperage: 40 A
• Poles: 3‑Pole
• Voltage rating: 600 V
• Compatibility note: Confirm fit and ratings before ordering. The part number 999340 is the best reference for ensuring proper compatibility with your panel or enclosure.

This circuit breaker is particularly well suited for upgrading or refurbishing industrial and commercial electrical panels that require a precise 3‑pole, 600V protection device. Use cases include retrofitting older gear to meet current safety standards, replacing failed breakers in three‑phase motor circuits, and integrating into service panels where matching Square D specifications helps preserve trip characteristics and panel labeling integrity.

Why choose the Square D 999340 for your project? It’s designed to align with Square D panel systems, helping maintain consistent performance and clear maintenance records. By sticking to the exact part number, you reduce the risk of mismatched trip curves or incompatible mounting footprints, which can lead to unnecessary downtime or panel rework.

Practical tips for installation and planning: Before purchase, verify that your panel accepts a 3‑pole, 600V device and that the feeder and branch circuit ratings align with 40 A protection. Keep the 999340 reference handy when discussing specs with suppliers or cross‑checking documentation, as it’s the clearest signal of compatibility for this particular model.

What's included A single Square D 999340 circuit breaker ready for installation in compatible Square D panels and enclosures.