Square D QOU370 Miniature Circuit Breaker

No. The QOU370 is a unit-mount circuit breaker designed for OEM panels, DIN rail systems, and specific QOU enclosures. It lacks the plug-on mounting design required to fit into standard Square D QO or Homeline residential load centers.

Yes. The QOU370 features a feed-thru design with reversible line and load box lugs. This allows panel builders to land the supply power on either the top or bottom terminals, offering greater flexibility when routing conductors inside control panels and enclosures.

Although the QOU370 is compatible with 35mm symmetrical DIN rails, it requires separate Square D QOU mounting accessories. You must install the appropriate DIN rail mounting feet onto the breaker frame before it can be securely snapped onto the rail.

Yes, the box lugs on the QOU370 are dual-rated for both copper (Cu) and aluminum (Al) conductors. Electricians should apply a listed joint compound or oxide inhibitor when terminating aluminum wire to prevent oxidation and ensure a reliable connection.

Yes. This circuit breaker is UL Listed as an HACR type device. It is fully certified to provide overcurrent protection for heating, air conditioning, and refrigeration motor loads that require an HACR-rated breaker on their equipment nameplate.

The LI designation means the breaker's thermal-magnetic trip unit provides both Long-Time (L) and Instantaneous (I) protection. The long-time thermal element protects the circuit against sustained overloads, while the instantaneous magnetic element trips immediately in the event of a short circuit.

Yes, this breaker includes the Square D Visi-Trip indicator. If the breaker trips due to an overload or short circuit, a highly visible red flag appears in the indicator window, allowing maintenance personnel to quickly identify the faulted circuit in a crowded control panel.