Zinsco Q30 Miniature Circuit Breaker

The Q30 is designed exclusively for use in legacy Zinsco and Sylvania load centers that accept Q-style plug-in circuit breakers.

Yes. Connecticut Electric manufactures the UBIZ30, which is an ETL listed, direct replacement for the original Zinsco Q30 and Sylvania Q30 circuit breakers.

Yes. After Sylvania acquired Zinsco in the 1970s, they continued manufacturing the same Q-series breakers under the Sylvania brand name. The Q30 and Sylvania Q30 are interchangeable.

The Q30 is part of the Zinsco thick series. As a 1-pole breaker, it occupies a single 3/4-inch space in the load center.

Yes. Legacy Zinsco panels are known for design flaws, particularly with the aluminum bus bars and breaker connection points, which can fail or arc over time. Many electricians recommend a complete panel upgrade rather than replacing individual breakers when feasible.

The Q30 utilizes a plug-in connection. It clips directly onto the aluminum bus bars found in Zinsco and Sylvania load centers. Ensure the bus bar is free of pitting or burn marks before installation.

A 30A, 120V single-pole breaker is commonly used for dedicated 120V circuits up to 3600 watts. Typical applications include 120V well pumps, bathroom heaters, 120V RV receptacles (TT-30), and small electric motors.

No. The Q30 features a proprietary clip design specific to Zinsco and Sylvania bus bars. It will not fit or safely connect to Challenger, Murray, or any other modern load centers.

The terminal lugs on the Q30 accept 14 AWG to 8 AWG copper or aluminum wiring. Always torque the terminal screws to the manufacturer specifications to prevent loose connections.

Before installing a replacement breaker, carefully inspect the panel bus bar for signs of arcing, pitting, or heat damage. If the bus bar is damaged, installing a new breaker will not resolve the underlying connection hazard.