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Square D LH36125 Molded Case Circuit Breaker

  • 125A
  • 3 Pole
  • I-Line
Square D LH36125
Molded Case Circuit Breaker
Brand Square D
SKU LH36125
Select Item Condition
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  • 125A
  • 3 Pole
  • I-Line

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LH36125

Square D LH36125 - 125A 3 Pole Molded Case Circuit Breaker

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$2,843.90 Check Stock

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Description

Part of the legacy L-Frame series, this 125-amp molded case circuit breaker mounts into Square D I-Line panelboards and switchboards. It provides reliable long-time and instantaneous (LI) protection for commercial and industrial electrical systems. While currently replaced by the PowerPact HGA36125, upgrading requires additional filler plates due to the smaller modern frame size. This unit features a 65kAIC rating at 240VAC and accommodates 1 AWG to 600 kcmil wiring via standard lugs.

Specifications

Key specifications
Brand Square D
Part Number LH36125
Series LH
Amperage 125A
Poles 3
Mounting Style I-Line
Voltage 240VAC, 480VAC, 600VAC, 250VDC
Phase 3
AIC Rating 65kA @ 240VAC, 35kA @ 480VAC, 25kA @ 600VAC, 50kA @ 250VDC
Fit and installation
Frame Type LH
Terminal Type Lugs
For Use With Square D I-Line Panelboards and Switchboards
Wire Gauge (1) 1 AWG-600 kcmil (Al/Cu) or (2) 1 AWG-250 kcmil (Al/Cu)
Max Wire 600 kcmil
Min Wire 1 AWG
Protection and operation
Trip Technology Thermal Magnetic
Trip Function Code LI
Trip Function Long-Time, Instantaneous
Trip Adjustability Fixed Thermal, Adjustable Magnetic
Standards and features
Available Options Shunt Trip, Auxiliary Switch, Undervoltage Release, Alarm Switch
Accessories Lugs (AL400LA)
Standards CSA C22.2 No. 5, IEC 60947-2, NEMA AB 1, UL 489
Approval CSA, HACR, IEC, UL
Temp Rating 40C
Construction Features HACR Rated, High Interrupting Capacity, Push-To-Trip, Trip-Free Mechanism

Product FAQs

10 answers
What type of panelboards accept the LH36125 breaker?

This breaker is designed exclusively for Square D I-Line panelboards and switchboards. It utilizes a plug-on I-Line connection that engages directly with the panel busbars.

Can I use the LH36125 in a standard load center?

No, this breaker features an I-Line plug-in connection. It is exclusively designed for commercial and industrial I-Line panelboards, and will not fit in standard QO or Homeline residential load centers.

What are the acceptable wire sizes and materials for the LH36125 terminals?

The factory-installed lugs accept either one 1 AWG to 600 kcmil conductor or two 1 AWG to 250 kcmil conductors per phase. Both aluminum and copper wires are permitted.

Does the LH36125 require a separate mounting bracket for installation?

No, this breaker features an I-Line style plug-in connection. The breaker jaws plug directly into the busbars of a compatible Square D I-Line panelboard or switchboard, eliminating the need for separate mounting brackets or strap kits.

How does the adjustable magnetic trip function work on this L-frame breaker?

While the thermal element for overload protection is fixed at 125A, the magnetic instantaneous trip (I) can be adjusted by the user to coordinate with downstream devices and handle specific inrush currents.

What does the "LI" trip function code mean on the LH36125?

The "LI" designation indicates that the breaker provides Long-Time (L) and Instantaneous (I) trip functions. The long-time function protects against sustained overloads, while the instantaneous function protects against sudden short circuits.

Is the LH36125 rated for DC applications?

Yes, this breaker is rated for DC systems, providing up to 50kA interrupting capacity at 250VDC and 20kA at 500VDC.

Can the LH36125 replace a Square D LA36125 circuit breaker?

Yes, the LH36125 shares the same physical L-frame footprint and I-Line mounting as the LA36125. It can serve as a direct replacement while offering a higher interrupting rating of up to 65kA at 240VAC.

What frame size is the LH36125?

It is a Square D L-frame molded case circuit breaker. It fits into the same panel space as other legacy L-frame breakers, such as the LA and Q4 series.

Does the LH36125 provide ground fault protection?

No, this breaker is equipped with a standard thermal-magnetic trip unit that provides long-time overload and instantaneous short-circuit protection. It does not include built-in ground fault or equipment protection functions.

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Reviews

5.0
Rated 5.0 out of 5 stars
Based on 2 reviews
Total 5 star reviews: 2 Total 4 star reviews: 0 Total 3 star reviews: 0 Total 2 star reviews: 0 Total 1 star reviews: 0
Rating
Ratings
2 reviews
  • ML
    Matthew L.
    Verified Buyer
    Reviewing
    Square D LH36400 - 400A 3 Pole Molded Case Circuit Breaker
    I recommend this product
    Rated 5 out of 5 stars
    7/21/26
    Super Breakers Does It Again!

    New, in excellent condition, cheaper and faster than the competition

  • MG
    Markus G.
    Verified Buyer
    Reviewing
    Square D LH36400 - 400A 3 Pole Molded Case Circuit Breaker
    I recommend this product
    Rated 5 out of 5 stars
    11/4/25
    it states correctly what it was

    Product as described