ZINSCO QB24-3060 U 60A 240V 3-pole Molded Case Circuit Breaker QB243060

Description:

The Zinsco QB24-3060 U (commonly referenced as QB243060) is a 60 Amp, 3-pole molded case circuit breaker designed for use in Zinsco / GTE Sylvania panelboards. It operates on 240V three-phase systems and features a thermal-magnetic (Magnatrip) trip mechanism to protect against 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. It has a typical interrupt rating of around 10 kAIC at 240V and includes load-side lug terminals.

Applications:

The Zinsco QB24-3060 breaker is commonly used in commercial and industrial electrical systems for three-phase circuits requiring 60A protection. Typical applications include motor control panels, machinery, pumps, compressors, and distribution feeders. It is installed in Zinsco bolt-on panelboards and is primarily used today for maintenance or replacement of legacy systems rather than new installations.

Technical Specifications:

• Manufacturer: Zinsco / GTE Sylvania / Challenger
• Model / Part Number: QB24-3060 U / QB243060
• Product Type: Molded Case Circuit Breaker (Bolt-On)
• Poles: 3-Pole
• Current Rating: 60 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)
• Terminals: Load-side lugs
• Status: Obsolete / discontinued

Common Replacements:

• Square D QOB360 3-Pole 60A Bolt-On Circuit Breaker
• Siemens BQD360 3-Pole 60A Bolt-On Breaker
• Eaton BAB3060H 3-Pole 60A Bolt-On Breaker