Zinsco QB241020 Molded Case Circuit Breaker

The Zinsco QB241020 Molded Case Circuit Breaker is a 20 Amp, single-pole bolt-on device built for Zinsco / GTE Sylvania panelboards and rated for 120 VAC. With a thermal-magnetic trip, it protects circuits from overloads and short circuits and has an interrupt rating of approximately 10 kAIC. As part of the QB24 series, it uses bolt-on mounting for secure connections in legacy installations and is commonly used on branch circuits such as kitchen outlets, laundry circuits, and garage receptacles needing 20 A protection. The QB24-1020 U is obsolete/discontinued; common replacements include Square D QO120 1-Pole 20A Circuit Breaker, Siemens Q120 1-Pole 20A Circuit Breaker, and Connecticut Electric UBIZ20 1-Pole 20A Zinsco Replacement Breaker.