SQUARE D
SQUARE D QO350 50A 3 Pole 120/240V AC circuit breaker
A 50 A three-pole miniature breaker for 120/240 V AC panels with 10 kA interrupting rating and plug-in mounting
- 50 A three-pole protection for 120/240 V AC circuits
- 10 kA interrupting rating handles heavy fault currents
- Plug-in mounting fits QO load centres and NQ panelboards
- 48 V DC rating adds low-voltage versatility
- Compact 3.1 × 2.3 × 2.9 in frame saves panel space
50 A Three-Pole Circuit Breaker
The Square D QO350 is a 50 A miniature circuit breaker designed for three-phase 120/240 V AC panels. It plugs directly into QO load centres and NQ panelboards, providing standard overcurrent protection for residential and light-commercial distribution boards.
10 kA Interrupting Rating and 48 V DC Capability
The breaker carries a maximum AIR of 10 kA at 120/240 V AC and is also rated for 48 V DC circuits. Its paddle actuator gives clear visual indication of trip status, while the plug-in mounting style allows quick installation without tools.
Lug Terminals and 100 A Frame Compatibility
Terminal lugs accept standard copper or aluminium conductors for secure connections. The unit fits the 100 A QO frame size, measuring 3.1 in long, 2.3 in wide and 2.9 in deep, and is rated for a minimum operating temperature of 77 °F.
Highlights
- 50 A three-pole protection for 120/240 V AC circuits
- 10 kA interrupting rating handles heavy fault currents
- Plug-in mounting fits QO load centres and NQ panelboards
- 48 V DC rating adds low-voltage versatility
- Compact 3.1 × 2.3 × 2.9 in frame saves panel space
Specifications
| Brand | SQUARE D |
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Questions about this item
How do I install the QO350 plug-in breaker into a QO load center and what step is often missed?
Align the breaker with the bus stabs in the QO load center and press firmly until it seats fully; the step often missed is verifying the paddle snaps completely into the locked position.
What maintenance or replacement will the QO350 need later?
No routine maintenance is required; replace the breaker if it trips repeatedly, shows discoloration at the lug terminals, or fails to reset after a fault.
What limit appears first under sustained load on the QO350?
The 50 A thermal trip curve opens the circuit when current exceeds the rated value for the time defined by the standard trip characteristic.
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