Zinsco QCB30 Molded Case Circuit Breaker
- 30A
- 2 Pole
- Bolt-On
Quantity
Zinsco QCB30 - 30A 2 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
Description
Maintaining legacy electrical systems requires exact-fit components like the Zinsco QCB30. This 30A, two-pole molded case circuit breaker provides reliable overcurrent defense for commercial and industrial environments. Designed with a robust bolt-on connection, it installs into vintage Zinsco panelboards seamlessly. For modern retrofits, this specific breaker is frequently replaced by the UBIZ230B equivalent. The thermal-magnetic trip unit offers a 10 kAIC interrupt capacity at 120/240VAC.Specifications
| Brand | Zinsco |
|---|---|
| Part Number | QCB30-R |
| Amperage | 30A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Terminal Type | Lugs |
|---|---|
| For Use With | Zinsco Panelboards |
| 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 |
| Accessories | Load Side Lugs Included |
|---|---|
| Standards | UL 489 |
| Approval | UL |
| Temp Rating | 40C |
Product FAQs
6 answersWhat type of panels accept the Zinsco QCB30 circuit breaker?
The QCB30 is designed exclusively for vintage Zinsco panelboards that require bolt-on connections. It will not fit in standard Zinsco load centers, which utilize plug-in style breakers.
How is the QCB30 installed into the panel?
This breaker uses a bolt-on mounting style. It must be mechanically bolted directly to the panelboard's bus bar, ensuring a secure and reliable connection for commercial or industrial environments.
Does the QCB30 come with lugs, and what wire sizes do they accept?
Yes, the breaker includes load-side lugs. These terminals accommodate copper or aluminum wire gauges ranging from #14 AWG up to #4 AWG.
What type of protection does the QCB30 trip unit provide?
It features a fixed thermal-magnetic trip unit with Long-Time and Instantaneous (LI) functions. The thermal component responds to prolonged overloads, while the magnetic component trips instantly during short circuits.
What is the modern equivalent for the Zinsco QCB30?
For modern retrofits and panel maintenance, this specific breaker is frequently replaced by the Connecticut Electric UBIZ230B, which is designed as an exact-fit equivalent for legacy Zinsco panelboards.
Are there safety concerns associated with legacy Zinsco breakers?
Yes, original Zinsco equipment is obsolete and often flagged by inspectors due to historical design flaws, such as failing to trip during overloads or fusing to the aluminum bus bar. While replacement breakers can restore functionality, many electricians recommend evaluating the entire panel for an upgrade.
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