Zinsco Q35 Miniature Circuit Breaker

The Q35 is designed exclusively for legacy Zinsco load centers that accept Type Q plug-on breakers. It features a specific clip design that connects to the Zinsco busbar and will not fit in modern panels from other manufacturers.

The Q35 uses a plug-on connection specific to Zinsco load centers. It clips directly onto the busbar without the need for mounting hardware. Due to the age of these panels, electricians should carefully inspect the busbar for pitting or arc damage before seating the breaker.

The Q35 terminal lugs accept copper or aluminum conductors from 8 AWG to 4 AWG. Because proper torque is critical to prevent thermal events, especially with aluminum wiring, always use a calibrated torque tool and follow the manufacturer specifications printed on the breaker label.

Legacy Zinsco panels and breakers have a documented history of failing to trip during overcurrent events and experiencing busbar arcing. While replacing the entire panel is often recommended, installing modern ETL-listed aftermarket replacements like the Connecticut Electric UBIZ35 is a safer way to maintain an existing system.

The Q35 utilizes a fixed thermal-magnetic trip unit. It includes a long-time delay for standard overloads and an instantaneous trip function to quickly clear severe short circuits.