The LLA36600U31X is a high-performance 600A electronic trip MCCB designed for demanding commercial and industrial environments. It mounts into Square D I-Line panelboards and switchboards, offering a modern replacement for legacy LC36600 and LI36600 breakers. Featuring a MicroLogic 3.3 trip unit, it provides adjustable long-time and instantaneous (LI) protection. With a robust 100 kAIC rating at 480VAC and true RMS sensing, this L-Frame breaker ensures reliable, current-limiting performance.
Which panelboards are compatible with the LLA36600U31X circuit breaker?
This breaker features a proprietary plug-in connection designed exclusively for Square D I-Line panelboards and I-Line switchboards. It will not fit in standard unit-mount or bolt-on enclosures.
What does the U31X suffix indicate on this PowerPacT L-frame breaker?
The U31X suffix designates that the breaker is equipped with a MicroLogic 3.3 electronic trip unit configured with load-side lugs. This module provides adjustable Long-Time and Instantaneous (LI) protection to allow for precise electrical system coordination.
What wire sizes are accepted by the mechanical lugs on the LLA36600U31X?
The factory-installed load lugs on this 600A breaker are designed to accept two conductors per phase, accommodating wire sizes from 2/0 AWG up to 500 kcmil for both copper and aluminum cables.
Can this 3-pole breaker be applied to single-phase circuits?
Yes, PowerPacT L-frame breakers equipped with MicroLogic trip units are listed for single-phase applications. However, manufacturer specifications restrict single-phase use to 240VAC systems only, utilizing any two of the three poles.
Are the interrupting ratings identical across all system voltages for the LLA36600U31X?
No, the interrupting capacity scales inversely with system voltage. This L-interrupting class breaker delivers 125kA at 240VAC, 100kA at 480VAC, and 50kA at 600VAC, requiring electrical planners to verify the available fault current at their specific operating voltage.
How are the line and load connections configured on this specific model?
As an I-Line style breaker, the line side features factory-installed plug-on jaws that lock directly onto the I-Line busbar stack. The load side is equipped with standard mechanical terminal lugs for outgoing cable connections.
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