Overview
The Square D QOB340 is a 40-ampere, 3-pole bolt-on miniature circuit breaker designed for industrial and commercial power distribution. Rated at 240 VAC with a short-circuit current rating of 10 kilo-Amps, this breaker provides robust overcurrent and short-circuit protection. HACR-rated for heating, air-conditioning, and refrigeration equipment, the QOB340 is ideal for applications requiring reliable thermal-magnetic trip protection.
Key Features
- Thermal-Magnetic Trip: Overcenter, trip-free toggle mechanism with quick-make, quick-break action; an overcurrent on any pole causes all poles to open simultaneously
- Visi-Trip Indication: Visual indication that the circuit breaker has tripped; the handle assumes a center position and a red Visi-Trip indicator appears in a window
- Box Lug Terminals: Accommodates 8 – 2 AWG copper and aluminum wires
- HACR Rated: Approved for use with heating, air-conditioning, and refrigeration equipment
- Compact Design: QO breakers use a compact 3/4 inch width design for small system footprint
Technical Specifications
- Frame Type: QO (Standard Miniature)
- Poles: 3
- Current Rating: 40 Amps
- Voltage Rating: 120/240 VAC, 48 VDC
- Interrupting Rating (AIC): 10 kilo-Amps at 120/240VAC; 5 kilo-Amps at 48 VDC
- Trip Type: Thermal-Magnetic
- Connection Type: Bolt-on connection
- Wire Compatibility: 8 to 2 AWG (Copper or Aluminum)
- Dimensions: 3.12″ Length × 2.25″ Width × 2.91″ Depth
- Weight: 0.85 lbs
- Operating Temperature: 104°F (40°C)
- Certifications: UL Listed (File E84967), CSA Certified (Master Contract 153555)
Typical Applications
QOB bolt-on circuit breakers are for use in NQO and NQOD panelboards. The HACR rating makes this breaker well-suited for:
- HVAC and refrigeration system protection
- Commercial and industrial power distribution panels
- AC and DC switchgear applications
- Equipment requiring quick-trip response and visual fault indication
Compatibility & Replacements
Compatible With
- NQO and NQOD panelboards
- Square D QO-series distribution systems
- Standard industrial control panels
- HVAC and refrigeration equipment assemblies
Replaces / Drop-In Replacement For
The QOB340 is a direct replacement for other Square D 40A, 3-pole QOB circuit breakers rated 240VAC with 10kA interrupting capacity. Verify model compatibility with your panelboard before ordering.
Works With
- Square D NQO and NQOD panelboards
- Optional factory-installed shunt trips and auxiliary switches
- Standard thermal-magnetic trip coordination schemes
- AC and DC control systems up to 48 VDC
