Zinsco QFP175-3 Molded Case Circuit Breaker
- 175A
- 3 Pole
- Plug-On
Quantity
Zinsco QFP175-3 - 175A 3 Pole Molded Case Circuit Breaker
New
Quantity
Description
Supplying 175 amps of three-phase power, this plug-on main breaker serves commercial and industrial facilities. It mounts into vintage Zinsco panelboards, offering an exact fit for aging electrical infrastructure. The thermal-magnetic trip mechanism delivers reliable long-time and instantaneous protection with a 10kAIC rating at 240VAC. For modern alternatives, the UBIZ3175 serves as a recognized substitute.Specifications
| Brand | Zinsco |
|---|---|
| Part Number | QFP175-3 |
| Series | QFP |
| Amperage | 175A |
| Poles | 3 |
| Mounting Style | Plug-On |
| Voltage | 240VAC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC |
| Terminal Type | Lugs |
|---|---|
| For Use With | Zinsco Panelboards |
| Wire Gauge | 1 AWG - 300 kcmil |
| Max Wire | 300 kcmil |
| Min Wire | 1 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Accessories | Load Side Lugs Included |
|---|---|
| Standards | UL 489 |
| Approval | UL |
| Temp Rating | 40C |
| Construction Features | Main Breaker |
Product FAQs
7 answersWhich electrical panels are compatible with the QFP175-3 circuit breaker?
This breaker is designed for use in legacy Zinsco, Sylvania, and Challenger panelboards that accept QFP-frame main or large branch breakers.
Are there other brands that manufacture the QFP175-3?
Yes. Because the original Zinsco product line changed ownership several times, you may find exact interchangeable equivalents branded under Sylvania, Challenger, or Thomas and Betts.
What wire sizes are accepted by the load side lugs on this breaker?
The load side lugs on the QFP175-3 accommodate wiring ranging from 1 AWG up to 300 kcmil. Ensure proper torque specifications are followed during installation.
How does the QFP175-3 mount into the panelboard?
It utilizes a plug-on connection, meaning it seats directly onto the panel busbars rather than bolting in place. Because of known issues with Zinsco bus connections, verify that the breaker seats tightly and securely without any looseness.
Are there any specific safety concerns when replacing a Zinsco main breaker?
Yes. Legacy Zinsco panelboards are known for design flaws where the busbars can degrade, arc, or burn over time. Before installing a replacement breaker, a licensed electrician must thoroughly inspect the panel busbars for pitting, corrosion, or heat damage. If the busbar is damaged, the entire panel typically requires replacement.
Is the QFP175-3 suitable for systems requiring a high interrupting capacity?
This breaker has a standard interrupting rating of 10kA at 240V. It is not suitable for commercial or industrial systems that require a high interrupting capacity, such as 22kAIC or 65kAIC, at this voltage. Always verify the available fault current of your system before installation.
Can the trip settings on the QFP175-3 be adjusted in the field?
No. This breaker features a fixed thermal magnetic trip unit. The long time and instantaneous trip functions are factory set and cannot be modified by the installer.
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 3 reviews.
- KYKathleen Y.Verified BuyerReviewingMilbank UQFP-100 2 Pole Circuit BreakerI recommend this productRated 5 out of 5 stars1/1/26Milbank 100 2 Pole Circuit Breaker
Product arrived on time, well packaged and exactly what we needed.
Jake was extremely helpful and courteous. You don’t find that too often these days. Will spread the word and recommend your company to all that require your service.
Thank you and Happy New Year
Sincerely,
K. Young
- QAquinlan a.Verified BuyerReviewingZinsco QFP2200T - 200A 2 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars8/26/25Great communication and customer service
Ordered QFP2200T breaker and paid to ship overnight. Reached out to company when breaker did not arrive on time. Although I did not get the breaker when expected, they did communicate the situation, refunded my shipping and expedited the breaker to me once it was ready for shipping. They handled the situation in the best possible way given the circumstances.
Would buy from them again.
-Quinlan (Q-Extra Electrical Services)
- ARAized R.ReviewingZinsco QFP2200T - 200A 2 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars10/7/21Excellent service!
I needed an obsolete part. They had it and sent it. Turned out it was the wrong part. Their customer service made up for it. They sent the correct part overnight and also sent a free ups label to return the wrong part. Great service! Highly recommend. And the refurbished part looked like it was in great shape.