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Zinsco Q50 Miniature Circuit Breaker
- 50A
- 1 Pole
- Plug-On
Zinsco
Q50
Miniature Circuit Breaker
Brand
Zinsco
SKU
Q50
Quantity
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Zinsco Q50 - 50A 1 Pole Miniature Circuit Breaker
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Description
A drop-in solution for aging infrastructure, the Zinsco Q50 delivers 50 amps of single-pole protection. It is engineered to maintain safe power distribution in older residential facilities. Designed to mount into original Zinsco panelboards, this plug-on breaker eliminates the need for complex retrofits. It is a reliable cross-reference for the UBIZ50, ensuring seamless compatibility. Delivering a 10kAIC capacity at 120/240VAC, it utilizes proven Magnetrip technology and a black handle.Specifications
| Brand | Zinsco |
|---|---|
| Part Number | Q50-R |
| Series | Q |
| Amperage | 50A |
| Poles | 1 |
| Mounting Style | Plug-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Terminal Type | Lugs |
|---|---|
| For Use With | Zinsco Load Centers |
| Wire Gauge | 8-4 AWG (Cu/Al) |
| Max Wire | 4 AWG |
| Min Wire | 8 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Standards | UL 489, HACR Rated |
|---|---|
| Approval | UL |
| Temp Rating | 40C |
| Construction Features | Magnetrip, Color-Coded Handle (Black) |
Product FAQs
7 answersWhat panels are compatible with the Zinsco Q50 circuit breaker?
The Q50 is designed for use in legacy Zinsco and Sylvania load centers that accept Type Q plug-in circuit breakers.
Is the Q50 considered a thick or thin series breaker?
The Q50 is a thick series breaker, measuring 3/4 inch wide per pole. It requires a full standard space in the load center, unlike Zinsco twin or thin breakers.
Is there a modern replacement for the obsolete Zinsco Q50?
Yes, Connecticut Electric manufactures a direct replacement under the catalog number UBIZ50. It is designed to fit the same Zinsco load centers and meets modern UL 489 safety standards.
What is the difference between Type Q and Type UBIZ breakers?
Type Q is the original Zinsco designation, while UBIZ is the modern replacement series manufactured by Connecticut Electric. Both fit the same 3/4 inch thick breaker spaces in Zinsco load centers.
Are there known safety concerns with older Zinsco circuit breakers?
Yes, legacy Zinsco panels and breakers have a documented history of safety issues, including breakers failing to trip during overloads and arcing due to poor bus bar connections. Many electricians recommend upgrading the entire panel when possible.
Can a Zinsco Q50 breaker weld to the bus bar?
Yes, one of the known failure modes of original Zinsco equipment is that the breakers can arc and weld themselves to the aluminum bus bar, preventing them from tripping or being safely removed. Always inspect the panel for heat damage.
How does the Q50 connect to the panel bus bar?
It utilizes a plug-in connection that clips directly onto the aluminum bus bars of compatible Zinsco panels. Due to known issues with these connections, ensure the bus bar is free of pitting or corrosion before installation.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 47 reviews.
Reviews Summary
Generated by AI from 91 most recent customer reviews
Last updated 8/1/25
Customers say these circuit breakers arrive quickly and match their specifications perfectly. Many reviews mention success finding hard-to-locate specialty breakers through this supplier. Common feedback includes praise for the accurate product descriptions, reliable shipping, and competitive pricing. While some note occasional stock limitations, users consistently report the breakers fit and function as intended.
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Rating
47 reviews
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The circuit breakers are at a great cost.
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The product was exactly what I needed and it arrived on time.
- DQDon Q.Verified BuyerReviewingSiemens Q3100 - 100A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars9/14/26Siemens breaker
Great customer experience, great prices and fast shipping... Definitely will be buying her again.
- CSChristopher S.Verified BuyerRated 5 out of 5 stars8/12/26Siemens 60
Perfect new condition
- GSGeorge S.Verified BuyerReviewingSiemens Q2150B - 150A 2 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars3/4/26Great service
Every time I call or go online you have the parts I'm looking for.