Engineered for industrial applications, the MEL36250LI is a 250A, 3-pole electronic trip circuit breaker by Square D. It delivers robust performance for complex electrical systems. This unit-mount MCCB fits Square D enclosures and switchboards. Belonging to the legacy M-Frame family, it can be upgraded to the modern PowerPacT L-Frame series (LJL36250U31X). Delivering 65kAIC at 480VAC, it utilizes true RMS sensing. The adjustable LI trip settings provide superior coordination capabilities.
What does the LI in the MEL36250LI part number indicate?
The LI designates the breaker's electronic trip functions. It features adjustable Long-Time protection for overload conditions and Instantaneous protection for short circuits, allowing for precise coordination within your electrical system.
Does the MEL36250LI include ground fault protection?
No, the LI trip unit only provides Long-Time and Instantaneous protection. It does not include Equipment Ground Fault protection. If ground fault protection is required, you will need a breaker with an LIG or LSIG trip unit.
Can the MEL36250LI be installed in an I-Line panelboard?
No, the MEL36250LI is a unit-mount, feed-thru circuit breaker. It cannot be field-modified for I-Line installations. You must use an I-Line specific M-Frame breaker for those applications.
Can I mount the MEL36250LI in a standalone enclosure?
Yes, this unit-mount breaker is compatible with Square D individual enclosures designed for M-Frame breakers, as well as standard Square D switchboards.
What are the wire size and material requirements for the MEL36250LI lugs?
The factory-installed feed-thru lugs accept three 3/0 AWG to 500 kcmil conductors per phase. They are dual-rated for both aluminum and copper wiring. Ensure proper torque specifications are applied during installation.
Is the MEL36250LI a direct replacement for older M-Frame breakers?
Yes, the MEL36250LI is part of the legacy M-Frame series and can replace older or failed MEL breakers with the same 250A rating and 3-pole configuration. Verify your required interrupting capacity and mounting style before replacing.
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