Square D A1B250 Molded Case Circuit Breaker
- 50A
- 2 Pole
- Bolt-On
Quantity
Square D A1B250 - 50A 2 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
Description
Providing reliable thermal-magnetic protection, this 50A molded case circuit breaker is built for demanding commercial and industrial applications. The two-pole unit safeguards electrical circuits against overloads and short circuits using fixed long-time and instantaneous trip functions. Installation is straightforward, as the breaker bolts firmly into compatible Square D NA1B panelboards.Specifications
| Brand | Square D |
|---|---|
| Part Number | A1B250-R |
| Series | A1B |
| Amperage | 50A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 240VAC |
| Frame Type | A1B |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D NA1B Panelboards |
| 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 Thermal, Fixed Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Undervoltage Release |
|---|---|
| Accessories | Load Side Lugs Included |
| Standards | CSA C22.2 No. 5, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Long Body, Visual Trip Indicator |
Product FAQs
7 answersWhat panelboards are compatible with the Square D A1B250?
The A1B250 is a bolt-on molded case circuit breaker designed specifically for legacy Square D NA1B panelboards. Because of its unique A1B frame, it cannot be installed in standard QO, NQOD, or I-Line load centers.
What wire sizes are compatible with the A1B250 load lugs?
The factory-installed load lugs accept 8 AWG to 4 AWG copper or aluminum wire. Always verify that the conductor size matches the 50A circuit requirements and follow standard torque specifications during installation.
Can the A1B250 be installed in 480V commercial electrical systems?
No. This breaker is rated for a maximum of 240VAC and 48VDC. It does not have the voltage rating or clearances required for 480V or 277V/480V applications.
How does the thermal-magnetic trip unit on the A1B250 operate?
The breaker uses a fixed thermal-magnetic mechanism with Long-Time and Instantaneous (LI) functions. The thermal component provides delayed tripping for sustained overloads, while the magnetic component trips the breaker immediately during a short circuit.
Can I adjust the trip settings on the A1B250?
No. The A1B250 features fixed thermal and fixed magnetic trip elements. Neither the overload nor the short-circuit trip thresholds can be adjusted in the field.
How is the A1B250 installed into the panelboard?
The A1B250 features a bolt-on connection type. It must be mechanically bolted directly to the busbar of a compatible NA1B panelboard, which provides a highly secure, vibration-resistant electrical connection.
Can the A1B250 be used in DC circuits?
Yes. While primarily used in 240VAC systems, the A1B250 is also rated for up to 48VDC, allowing it to be used in compatible low-voltage direct current control or distribution circuits.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 2 reviews.
- NLNoble L.ReviewingSquare D A1B115 - 15A 1 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars7/19/21Great Service, On Time Delivery, Great Price
SuperBreakers is my a dependable source to meet my customer's requirements at a good value and with on time delivery. When you throw in great customer service, you can't beat that combination.
- CHCobe H.ReviewingSquare D A1B120 - 20A 1 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars2/11/19Repeat customer
Although these breakers are refurbished they work great. It beats having to change the whole panel because of one breaker.