Square D A1B240 Molded Case Circuit Breaker
- 40A
- 2 Pole
- Bolt-On
Quantity
Square D A1B240 - 40A 2 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
Description
Part of the A1B miniature series, this 40A molded case circuit breaker provides reliable overcurrent protection for commercial and industrial applications. The two-pole unit utilizes thermal-magnetic trip technology with fixed long-time and instantaneous functions to safeguard electrical systems. Engineered for specific installations, the breaker bolts securely into Square D NA1B panelboards.Specifications
| Brand | Square D |
|---|---|
| Part Number | A1B240-R |
| Series | A1B |
| Amperage | 40A |
| 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, Alarm Switch |
|---|---|
| Accessories | Load Side Lugs Included |
| Standards | CSA C22.2 No. 5, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Visual Trip Indicator, Long Body |
Product FAQs
5 answersWhat panelboards accept the Square D A1B240 circuit breaker?
The A1B240 is engineered specifically for legacy Square D NA1B panelboards. These vintage commercial and industrial distribution panels require the A1B frame type and will not accept modern QO or QOB series breakers.
Can the A1B240 be used in DC electrical systems?
Yes, in addition to its primary 240VAC rating, the A1B240 is rated for up to 48VDC. This allows it to be utilized in specific low-voltage direct current control circuits or battery backup applications.
Is the Square D A1B240 still in active production?
No, the A1B series is an obsolete legacy frame originally manufactured for older commercial distribution systems. Exact replacements like the A1B240 are sourced specifically to maintain existing NA1B panelboards without requiring a complete panel upgrade.
How does the thermal-magnetic trip mechanism function on the A1B240?
The breaker uses a fixed LI (Long-Time, Instantaneous) trip profile. The thermal element provides long-time delay protection against gradual overloads, while the magnetic element delivers instantaneous tripping to safely clear severe short circuits.
Can the A1B240 be used to replace a Y1B series breaker?
No. While they share a similar vintage design, A1B breakers are rated for 240VAC maximum and fit NA1B panels. Y1B breakers are the 277VAC equivalents designed for different panelboards. You must match the breaker frame to your specific panelboard and system voltage.
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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.