Rated for heavy-duty industrial use, the Square D Q422400AC is a 2-pole, 400A molded case circuit breaker. It utilizes a thermal-magnetic trip unit with fixed thermal and adjustable magnetic settings, delivering precise long-time and instantaneous (LI) protection. Featuring an I-Line plug-on mounting style, it installs seamlessly into Square D I-Line panelboards and switchboards. For facilities upgrading systems, this legacy Q-frame model is officially replaced by the LGA36400U31X.
What panelboards are compatible with the Q422400AC circuit breaker?
This breaker is designed exclusively for Square D I-Line panelboards and switchboards. It features a plug-on line connection and cannot be used in standard NQ or NF panels.
What does the AC suffix mean in the Q422400AC catalog number?
The AC suffix indicates the phase connection. It means this 2-pole breaker is factory-configured to connect to the A and C phases on a 3-phase I-Line bus.
What size wire can be used with the load lugs on this 400A breaker?
The load lugs accept either a single 1 AWG to 600 kcmil aluminum or copper wire, or two 1 AWG to 250 kcmil aluminum or copper wires per phase.
Are the trip settings adjustable on the Q422400AC?
Yes, this thermal-magnetic breaker features a fixed thermal trip for overload protection and an adjustable magnetic trip for short-circuit protection.
Is the Square D Q422400AC still in active production?
No, the Q4 frame is a legacy series that was discontinued by Schneider Electric. It remains widely used for replacements and expansions in existing I-Line switchboards.
Does this breaker include a push-to-trip feature?
Yes, it includes a push-to-trip button on the front of the breaker. This allows you to manually trip the mechanism to verify proper operation without exposing yourself to live parts.
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