Free Shipping Over $99
Zinsco QC250 Molded Case Circuit Breaker
- 50A
- 2 Pole
- Plug-On
Zinsco
QC250
Molded Case Circuit Breaker
Brand
Zinsco
SKU
QC250
Quantity
Shop with Confidence
Add an extra year of protection in your cart.
Zinsco QC250 - 50A 2 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
Similar Items
20A 2 Pole Molded Case Circuit Breaker
15A 2 Pole Molded Case Circuit Breaker
100A 2 Pole Molded Case Circuit Breaker
Description
Manufactured for obsolete electrical panels, the Zinsco QC250 is a 50-amp, two-pole circuit breaker. It provides dependable thermal-magnetic trip functions for standard residential and commercial applications. This plug-on breaker mounts into legacy Zinsco load centers, ensuring exact compatibility for older infrastructure. When seeking a newly manufactured equivalent, the UBIZ250 serves as the direct substitute.Specifications
| Brand | Zinsco |
|---|---|
| Part Number | QC250 |
| Series | QC |
| Amperage | 50A |
| Poles | 2 |
| Mounting Style | Plug-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | QC |
|---|---|
| Terminal Type | Lugs |
| For Use With | Zinsco Load Centers |
| Wire Gauge | 14-4 AWG |
| Max Wire | 4 AWG |
| Min Wire | 14 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Standards | UL 489 |
|---|---|
| Approval | UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated |
Product FAQs
8 answersWhat load centers are compatible with the Zinsco QC250?
The QC250 is designed exclusively for use in legacy Zinsco load centers. It will not fit in modern panels from other manufacturers.
Can I use the QC250 in a Sylvania electrical panel?
Yes, if the panel is a GTE Sylvania panel that specifically accepts Zinsco QC style breakers. GTE Sylvania purchased Zinsco and continued manufacturing panels that use the exact same breaker footprint.
Is there a modern aftermarket replacement for the Zinsco QC250?
Yes, the Connecticut Electric UBIZ250 is a newly manufactured, direct aftermarket replacement for the 50-amp, 2-pole Zinsco QC250.
Are there known safety concerns with legacy Zinsco circuit breakers?
Yes. Legacy Zinsco panels and breakers have documented safety issues, including breakers failing to trip during overcurrent events and breakers welding to the bus bar. Many electricians recommend replacing the entire panel when these issues are present.
Can a faulty QC250 breaker cause damage to the panel bus bar?
Yes. A common failure mode for legacy Zinsco breakers is poor contact with the bus bar, which can lead to arcing, overheating, and the breaker melting or welding itself to the bus bar.
How does the QC250 connect to the panel bus bar?
The QC250 uses a plug-on mounting style, clipping directly onto the bus bar in compatible Zinsco load centers. Ensure the bus bar is free of corrosion or pitting before installation, as Zinsco panels are prone to bus bar degradation.
What wire sizes are accepted by the lugs on the QC250?
The terminal lugs accept wire gauges from 14 AWG to 4 AWG. Ensure you use the correct wire size for a 50-amp circuit, which is typically 6 AWG for copper or 4 AWG for aluminum, depending on the insulation type and local electrical codes.
What does the LI trip function code mean on this breaker?
The LI designation indicates that the breaker features both Long-Time and Instantaneous trip functions. The long-time function protects against sustained overloads, while the instantaneous function trips immediately during a short circuit, providing standard thermal-magnetic protection.
SuperClub
Join free. Get 500 SuperPoints.
Earn points on eligible purchases and redeem them at checkout.
100 SuperPoints = $1 off.
Warranties
Add an extra year of protection
60-Day Warranty
Your purchase includes 60 days of SuperBreakers warranty coverage.
Add a 1-year warranty extension in your cart.
Get a Quote
Don’t see what you’re looking for?
We source obsolete and hard-to-find parts every day.
Shipping
Free Shipping Policy
Parcel shipments with item value over $99 qualify for free economy shipping within the continental US. Please call to confirm special handling instructions. We do not charge a handling fee or require a minimum amount on any order. SuperBreakers does not ship on customer accounts.
Same Day Shipping
We strive to ship out your items the same day the order is placed. In rare circumstances SuperBreakers may reserve up to 5 business days to consolidate orders for complete shipment.
Expedited Shipments
Orders being shipped via Next Day Air, 2 Day Shipping or 3 Day Shipping must be received by 3 PM EST to guarantee same-day shipments. Expedited orders only ship on normal business days. Shipments will NOT be sent out on Saturdays and Sundays.
International Shipping
All International orders require a $1,000 minimum order threshold. Due to the special nature of these shipments, we require that these be placed with a SuperBreakers representative. Additional shipping and instructions will apply. All International Orders are Non-Cancel and Non-Refundable.
Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 15 reviews.
Total 5 star reviews: 15 Total 4 star reviews: 0 Total 3 star reviews: 0 Total 2 star reviews: 0 Total 1 star reviews: 0
Search
Rating
15 reviews
- DSDenise S. A.Verified BuyerReviewingEaton / Cutler-Hammer QC3070H - 70A 3 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars8/4/25Great turn around!
My experience was great. I had the item quickly; and it was more reasonably priced than other places I checked. Not having to pay freight was an absolute bonus.
- DMDouglas M.Verified BuyerReviewingEaton / Cutler-Hammer QC1020 - 20A 1 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars7/28/25Just what I needed
Ordering was easy and the processing was immediate. The beakers I ordered was exact. I recommend this company for your needs.
- GLGianna L.ReviewingEaton / Cutler-Hammer QC1015 - 15A 1 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars11/27/23Great
as advertised!
- EDElmer D.ReviewingZinsco QCAL100 - 100A 2 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars10/28/23Very accurate, delivered on time
Very accurate, delivered on time and fixed my problem good job
- RBRawle B.ReviewingEaton / Cutler-Hammer QC1015 - 15A 1 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars8/8/23SuperBreakers had the parts I
SuperBreakers had the parts I needed in stock, was shipped and delivered on time. Great service!