ZINSCO QB24-3015 U 15A 240V 3-pole Molded Case Circuit Breaker QB243015

Description:

The Zinsco QB24-3015 U (commonly referenced as QB243015) is a 15 Amp, 3-pole molded case circuit breaker designed for use in Zinsco / GTE Sylvania panelboards. It operates at 240V and features a thermal-magnetic trip mechanism (Magnatrip style) to protect circuits from overloads and short circuits. This breaker belongs to the QB24 series and uses a bolt-on mounting design for a secure connection to the panel bus in three-phase systems.

Applications:

The Zinsco QB24-3015 breaker is commonly used in commercial and industrial electrical systems requiring three-phase 15A protection, such as motor control circuits, control panels, and small machinery loads. It functions as a branch or feeder breaker in Zinsco bolt-on panelboards and is primarily used today for maintenance or replacement of legacy equipment. 

Technical Specifications:

• Manufacturer: Zinsco / GTE Sylvania / Challenger
• Model / Part Number: QB24-3015 U / QB243015
• Product Type: Molded Case Circuit Breaker (Bolt-On)
• Poles: 3-Pole
• Current Rating: 15 Amps
• Voltage Rating: 240 VAC
• Phase: 3-phase
• Interrupt Rating: ~10 kAIC @ 240V
• Mounting: Bolt-on (QB series)
• Trip Type: Thermal-magnetic (LI – long-time & instantaneous)
• Function: Overcurrent and short circuit protection
• Status: Obsolete / discontinued

Common Replacements:

• Square D QOB315 3-Pole 15A Bolt-On Circuit Breaker
• Siemens BQD315 3-Pole 15A Bolt-On Breaker
• Eaton BAB3015H 3-Pole 15A Bolt-On Breaker