Square D QOB340 Miniature Circuit Breaker

Yes, if you are installing them in a Square D NQ or legacy NQOD panelboard. Both NQ and NQOD panelboard interiors are engineered to accept either plug-on QO or bolt-on QOB branch circuit breakers. However, bolt-on models like the QOB340 are often preferred in commercial applications for a more secure connection.

Yes. This thermal magnetic circuit breaker is HACR rated, meaning it is certified for use with compatible heating, air conditioning, and refrigeration equipment requiring a 40-amp, 3-pole overcurrent protection device.

The box lugs on the QOB340 accept 8 to 2 AWG copper or aluminum wire and require a tightening torque of 44.3 lb-in (5 N.m) to ensure a safe, secure electrical connection.

The breaker features a built-in Visi-Trip indicator. When the device trips due to an overload or short circuit, the handle rests in a center position and a bright red indicator appears in a small window, allowing for fast troubleshooting in the panelboard.

Bolt-on breakers attach directly to the panelboard bus bar with a screw. This mechanical connection prevents the breaker from vibrating loose over time or during heavy load cycling, ensuring a secure and reliable connection in demanding commercial and industrial environments.