Square D QO340 Miniature Circuit Breaker

No. Square D QO and Homeline (HOM) are two distinct breaker formats. The QO340 features a 3/4-inch per pole width and plug-on design that is only compatible with QO load centers and NQ panelboards.

Because standard QO breakers feature a compact 3/4-inch width per pole, this 3-pole breaker requires three adjacent spaces on the panel bus.

Yes, this breaker is HACR rated, making it suitable and code-compliant for use with dedicated heating, air conditioning, and refrigeration loads.

No. The QO340 is a standard thermal-magnetic breaker that provides basic overload and short-circuit protection. It does not include GFCI or AFCI functionality.

Yes. This breaker features the Square D Visi-Trip indicator. When a trip occurs, the handle snaps to a midpoint position and reveals a highly visible red flag, allowing for rapid identification of the faulted circuit.

The box lugs on this breaker are generally rated for a tightening torque of 44.3 lb-in (5 N.m). Always verify the exact torque specification printed directly on the breaker label before terminating your conductors.

The QO340 utilizes a plug-on mounting design intended for QO load centers and standard NQ panelboards. The QOB340 provides the identical 40-amp, 3-pole protection but features a bolt-on connection required for secure mounting in NQOD and some NQ industrial panelboards.

Yes, the QO340 can be back-fed. However, when used as a back-fed main, the National Electrical Code requires the installation of an approved breaker retaining kit to mechanically secure it to the panel bus.