Zinsco Q140 Magnatrip Single Pole Circuit Breaker

The Zinsco Q140 Magnatrip single-pole circuit breaker is a 40-amp, plug-in device designed for use in Zinsco and GTE Sylvania load centers. It operates on 120/240 VAC and uses a thermal-magnetic Magnatrip trip mechanism to protect against overloads and short circuits. This 1-pole breaker is commonly found in older residential panels and is intended for residential and light commercial branch circuits that require 40 A protection, such as air conditioning units, electric heaters, compressors, and dedicated appliance circuits. With an interrupt rating of approximately 10 kAIC, the Q140 is discontinued/obsolete and is commonly replaced by Siemens Q140, Square D QO140, or Connecticut Electric UBIZ40 in legacy installations.