Zinsco QB24-2060U Molded Case Circuit Breaker

The Zinsco QB24-2060U is a 60 Amp, 2-pole molded case circuit breaker designed for Zinsco / GTE Sylvania panelboards. It operates on 240V systems and uses a thermal-magnetic trip mechanism to protect circuits from overloads and short circuits. This bolt-on breaker from the QB24 series provides a secure electrical connection to the panel bus in residential and light commercial distribution. Technical details: Manufacturer—Zinsco / GTE Sylvania / Challenger; Product Type—Molded Case Circuit Breaker (Bolt-On); Poles—2; Current Rating—60 Amps; Voltage Rating—240 VAC; Mounting—Bolt-on (QB series); Trip Type—Thermal-magnetic; Interrupt Rating—~10 kAIC @ 240V (typical); Status—Obsolete / discontinued (surplus market availability). Common applications include 240V circuits requiring 60A protection in residential and light commercial systems, such as HVAC systems, electric heaters, subpanels, and large appliances. Common replacements in the market include Connecticut Electric UBIZ260 2-Pole 60A Zinsco replacement breaker, Siemens Q260 2-Pole 60A Circuit Breaker, and Square D QOB260 2-Pole 60A Bolt-On Circuit Breaker.