Engineered for industrial applications, the Square D KA26125AB delivers reliable overcurrent protection. This 2-pole, 125A molded case circuit breaker utilizes thermal-magnetic trip technology with long-time and instantaneous functions. Designed for Square D I-Line panelboards and switchboards, it features plug-on mounting and an AB phase connection. This legacy K-Frame unit is replaced by the PowerPact HGA261251 for modern upgrades. Rated 25kAIC at 480VAC, it includes a Visi-Trip indicator.
What panelboards are compatible with the KA26125AB circuit breaker?
This breaker is designed exclusively for use in Square D I-Line panelboards and switchboards. It features an I-Line style plug-in connection on the line side.
What does the AB suffix mean in the KA26125AB catalog number?
The AB suffix indicates the factory-configured phase connection. This 2-pole breaker is designed to connect to the A and B phases on the I-Line bus.
What wire sizes are accepted by the lugs on this breaker?
The load-side lugs accept wire gauges from 4 AWG to 350 kcmil. They are compatible with both aluminum and copper conductors.
How does this breaker mount into the panel?
It uses an I-Line style plug-in connection for the line side, which mounts directly onto the panelboard bus, and features standard lugs for the load-side wire connections.
What does the LI trip function code indicate?
The LI code means the thermal-magnetic trip unit provides Long-Time overload protection and Instantaneous short-circuit protection.
Is the trip unit on the KA26125AB adjustable?
Yes, it features a fixed thermal element for overload protection and an adjustable magnetic element, allowing you to set the instantaneous short-circuit trip threshold.
Is the KA26125AB rated for direct current systems?
Yes, this breaker is rated for both AC and DC systems. It supports up to 600VAC and is also rated for 250VDC with a 10kA interrupting capacity.
Is the Square D KA frame still in active production?
The KA frame is a legacy molded case circuit breaker. Square D has replaced the legacy K-frame series with the newer PowerPact H-frame breakers for modern installations.
SuperClub
Join free. Get 500 SuperPoints.
Earn points on eligible purchases and redeem them at checkout.
We source obsolete and hard-to-find parts every day.
Shipping
Free Shipping Policy
Parcel shipments with item value over $99 qualify for free economy shipping within the continental US. Please call to confirm special handling instructions. We do not charge a handling fee or require a minimum amount on any order. SuperBreakers does not ship on customer accounts.
We strive to ship out your items the same day the order is placed. In rare circumstances SuperBreakers may reserve up to 5 business days to consolidate orders for complete shipment.
Expedited Shipments
Orders being shipped via Next Day Air, 2 Day Shipping or 3 Day Shipping must be received by 3 PM EST to guarantee same-day shipments. Expedited orders only ship on normal business days. Shipments will NOT be sent out on Saturdays and Sundays.
International Shipping
All International orders require a $1,000 minimum order threshold. Due to the special nature of these shipments, we require that these be placed with a SuperBreakers representative. Additional shipping and instructions will apply. All International Orders are Non-Cancel and Non-Refundable.
Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 14 reviews.
Square D KA36150 - 150A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
7/27/26
Square D KA36150
As usual, on time and in great condition!
SJ
Shawn J.
Verified Buyer
Reviewing
Square D KA36225 - 225A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
4/27/26
I Line BreKER
Found exactly what I was looking for. They called and set over specs so I could confirm the fit!
RF
Ron F.
Verified Buyer
Reviewing
Square D KA36100 - 100A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
4/9/26
Multiple orders
I have purchased multiple breakers (of fairly large size) from SuperBreakers and their pricing has been excellent and the delivery time spot on. I would highly recommend them
MF
Matt F.
Verified Buyer
Reviewing
Square D KA36100 - 100A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
8/21/25
Order Messed Up - Breaker Great
I have ordered many breakers through SuperBreakers with no issues until this order. I ordered this breaker and it wasn't shipped. I sent a message and was told that a mistake was make in shipping and that they would next day air the breaker to me. 5 days later (weekend in there) the breaker arrived. Not next day air, but shit happens. Sent the breaker still in the box out with my electrician and received a call from him that the breaker that was sent was a KAL36100 not the KA36100. I reached out to SuperBreakers and was told the correct breaker would be next day aired that day and I was emailed a shipping label to send back the incorrect one. This time it arrived the next day and was installed. This error cost my customer a couple days with out power to a dimmer cabinet and about 2 extra hours of labor, but all was okay in the end. Mistakes happen. The help and quick responses to my emails I received from Mike David showed me enough about this company. I look forward to my next order. Thank you for working this situation out in timely manor.
JH
Joel H.
Verified Buyer
Reviewing
Square D KA36200 - 200A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
8/5/25
Worked As Planned
They had what we needed to match existing equipment, they shipped the same day and we put it right into service, no problems from first phone call to delivery and install.