Zinsco QFB150-2 Molded Case Circuit Breaker
- 150A
- 2 Pole
- Bolt-On
Quantity
Zinsco QFB150-2 - 150A 2 Pole Molded Case Circuit Breaker
New
Quantity
Description
Serving as a reliable main breaker, this 150-amp Zinsco component provides essential thermal-magnetic protection for commercial and industrial applications. It installs seamlessly into older Zinsco panelboards without requiring aftermarket adapters or modifications. Designed to replace UBIZ150 and UBITBFP1502 models, the unit features proven Magnatrip technology and delivers a 10kA interrupting capacity at 240VAC to maintain system safety.Specifications
| Brand | Zinsco |
|---|---|
| Part Number | QFB150-2 |
| Series | QFB |
| Amperage | 150A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 240VAC |
| Terminal Type | Lugs |
|---|---|
| For Use With | Zinsco Panelboards |
| Wire Gauge | #4 AWG - 300 kcmil |
| Max Wire | 300 kcmil |
| Min Wire | #4 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Fixed Magnetic |
| Accessories | Load Side Lugs Included |
|---|---|
| Standards | UL 489 |
| Approval | UL |
| Temp Rating | 40C |
| Construction Features | Main Breaker, Magnatrip |
Product FAQs
5 answersCan I use a Challenger or Sylvania QFB150-2 to replace a Zinsco QFB150-2?
Yes. Sylvania and Challenger acquired the Zinsco product lines and continued manufacturing the QFB series. A QFB150-2 from any of these three brands is physically and electrically identical and can be used interchangeably.
Is the QFB150-2 interchangeable with Zinsco Q type plug-in breakers?
No. The QFB series features a bolt-on connection designed for specific Zinsco commercial panelboards. It will not fit in residential load centers that require Q series plug-in breakers.
What size wire is accepted by the load side lugs on this 150A breaker?
The factory installed load lugs accept aluminum or copper wire ranging from #4 AWG up to 300 kcmil. Ensure proper torque specifications are followed during installation.
What does the LI trip function indicate on the QFB150-2?
The LI designation means the thermal magnetic trip unit provides Long-Time (thermal) protection against overloads and Instantaneous (magnetic) protection against short circuits. Both settings are fixed on this model.
Are there any special considerations when replacing a Zinsco bolt-on breaker?
When replacing legacy Zinsco breakers, thoroughly inspect the panel busbars for signs of pitting, arcing, or thermal damage. If the busbar is damaged, installing a replacement breaker will not resolve the underlying connection issue.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 2 reviews.
- RFRuss F.Verified BuyerReviewingMilbank UQFB-150 2 Pole Circuit BreakerI recommend this productRated 5 out of 5 stars6/26/26Breaker Purchase
This product arrived very quickly...in one day!
It was advertised and was installed successfully
- DDdaniel d.Verified BuyerReviewingMilbank UQFB-150 2 Pole Circuit BreakerI recommend this productRated 5 out of 5 stars3/4/26good
fits perfectly in the 320 we have. no problems