Square D QO Miniature Circuit Breakers Circuit Breakers
The Square D QO series is the most widely installed residential and light commercial miniature circuit breaker line in North America. QO breakers feature plug-in mounting for tool-free installation in Square D QO load centers, a Visi-Trip indicator that clearly shows the tripped state, and thermal-magnetic trip protection providing both overload and short-circuit protection. The QO series is SWD rated for switching fluorescent lighting loads and HACR rated for heating, air conditioning, and refrigeration equipment. The AllBreakerSales.com catalog includes the complete QO lineup in 1-pole (15A–60A) and 2-pole (15A–60A) configurations. Request a written quote to confirm the required catalog number and current availability.
Series Specifications
| Frame | QO Miniature — QO Frame |
|---|---|
| Amperage Range | 15A – 60A |
| Voltage | 120/240VAC |
| Poles | 1-Pole, 2-Pole |
| Interrupting Rating | 10kA @ 120/240V |
| Mounting | Plug-In |
| Trip Type | Thermal Magnetic |
History and Replacement Context
The Square D QO series was introduced in the 1950s and has become the dominant residential circuit breaker in the United States. The QO designation stands for Quick-Open, referring to the breaker's fast-acting trip mechanism. The QO series is manufactured by Schneider Electric and is used in millions of homes and light commercial buildings across North America.
Typical Applications
- Residential branch circuit protection (lighting, outlets, small appliances)
- Light commercial branch circuit protection
- HVAC branch circuit protection (HACR rated)
- Fluorescent lighting circuits (SWD rated)
- 240V appliance circuits (dryers, ranges, water heaters, A/C)
- EV charger branch circuits (Level 2, 240V)
Available Catalog Numbers
- QO120 — 20A, 1 pole, 120VAC
- QO115CAFIC — 15A, 1 pole, 120VAC
- QO120CAFIC — 20A, 1 pole, 120VAC
- QO1015 — 15A, 1 pole, 120VAC
- QO1020 — 20A, 1 pole, 120VAC
- QO1025 — 25A, 1 pole, 120VAC
- QO1030 — 30A, 1 pole, 120VAC
- QO1040 — 40A, 1 pole, 120VAC
- QO1050 — 50A, 1 pole, 120VAC
- QO1060 — 60A, 1 pole, 120VAC
- QO2015 — 15A, 2 pole, 240VAC
- QO2020 — 20A, 2 pole, 240VAC
- QO2025 — 25A, 2 pole, 240VAC
- QO2030 — 30A, 2 pole, 240VAC
- QO2040 — 40A, 2 pole, 240VAC
- QO2050 — 50A, 2 pole, 240VAC
- QO2060 — 60A, 2 pole, 240VAC
- QO2070 — 70A, 2 pole, 240VAC
- QO2080 — 80A, 2 pole, 240VAC
- QO2090 — 90A, 2 pole, 240VAC