Square D LA26300AC Molded Case Circuit Breaker
- 300A
- 2 Pole
- I-Line
Square D
LA26300AC
Molded Case Circuit Breaker
Brand
Square D
SKU
LA26300AC
Quantity
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Square D LA26300AC - 300A 2 Pole Molded Case Circuit Breaker
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300A 2 Pole Molded Case Circuit Breaker
300A 2 Pole Molded Case Circuit Breaker
Description
Built for demanding electrical systems, the Square D LA26300AC is a 2-pole, 300A molded case circuit breaker. It utilizes a thermal-magnetic trip mechanism to deliver reliable long-time and instantaneous (LI) protection. This unit mounts into Square D I-Line panelboards. It is a legacy L-Frame breaker, replaceable by the PowerPacT LJA36300U31X series when modernizing switchgear. Featuring an AC phase connection, it is rated 42kAIC at 240VAC and includes an adjustable magnetic trip.Specifications
| Brand | Square D |
|---|---|
| Part Number | LA26300AC |
| Series | LA |
| Amperage | 300A |
| Poles | 2 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 480VAC, 600VAC, 250VDC |
| Phase | 1 |
| AIC Rating | 42kA @ 240VAC, 30kA @ 480VAC, 22kA @ 600VAC, 10kA @ 250VDC |
| Frame Type | LA |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D I-Line Panelboards and Switchboards |
| Wire Gauge | 1 AWG-600 kcmil (Al/Cu) or (2) 1 AWG-250 kcmil (Al/Cu) |
| Max Wire | 600 kcmil |
| Min Wire | 1 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Adjustable Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Undervoltage Release, Alarm Switch, Padlock Attachment |
|---|---|
| Accessories | A-C Phase Connection (Factory Configured) |
| Standards | CSA C22.2 No. 5, UL 489 |
| Approval | CE, CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, Phase Connection AC |
Product FAQs
8 answersWhat type of panelboard accepts the LA26300AC?
This breaker is designed exclusively for Square D I-Line panelboards and switchboards. It features an I-Line style plug-in connection on the line side.
What does the AC suffix indicate on the LA26300AC catalog number?
The AC suffix specifies the phase connection configuration. It indicates that the breaker jaws are configured to connect to the A and C phases on the I-Line bus.
What wire sizes are accepted by the load lugs on this 300A breaker?
The load side lugs accept a single 1 AWG to 600 kcmil aluminum or copper wire, or two 1 AWG to 250 kcmil aluminum or copper wires.
Can the LA26300AC be used in DC applications?
Yes, this breaker is rated for up to 250VDC with an interrupting capacity of 10 kA, in addition to its standard AC voltage ratings.
Is the LA frame still the current standard for Square D 300A breakers?
The LA frame is a legacy molded case circuit breaker. While still widely supported and available for existing I-Line panels, the modern equivalent for new installations is the Square D PowerPact L frame series.
Can I install this breaker in a standard QO or NQ load center?
No. The LA26300AC utilizes an I-Line plug-in mounting system and will not fit in standard QO, NQ, or other residential and light commercial load centers.
Are the trip settings adjustable on the LA26300AC?
This thermal magnetic breaker features a fixed thermal trip for long time overload protection and an adjustable magnetic trip for instantaneous short circuit protection.
What safety precautions apply when installing this I-Line breaker?
Ensure the panelboard is fully de-energized before installation. Verify that the A-C phase configuration matches your system load requirements and that the I-Line bus is clean to ensure a secure plug-in connection.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 13 reviews.
Total 5 star reviews: 13 Total 4 star reviews: 0 Total 3 star reviews: 0 Total 2 star reviews: 0 Total 1 star reviews: 0
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Rating
13 reviews
- RGRobert G.Verified BuyerReviewingSquare D LA36400 - 400A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars7/16/26LA36400
Perfectly boxed and arrived on time. Thanks for the shirt and stickers as well.
- CECraig E.Verified BuyerReviewingEaton / Cutler-Hammer LA3600 - 600A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars10/13/25Westinghouse breaker
Excellent customer service and quick shipping
- CLClifton L.Verified BuyerReviewingSquare D LA36400 - 400A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars9/30/25estimator
Good
- BCBenjamin C.Verified BuyerReviewingEaton / Cutler-Hammer LA3225 - 225A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars8/4/25Refurbished Breaker
Breaker seems to be working great, no complaints from Client
- JMJerry M.ReviewingEaton / Cutler-Hammer LA3400 - 400A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars3/14/23Where is my breaker?
Where is my breaker?