Built for commercial and industrial applications, the Square D Q4L3400 is a 3-pole, 400A molded case circuit breaker. It provides long-time and instantaneous (LI) trip functions to protect electrical systems against overloads and short circuits. This unit mount MCCB installs into Square D switchboards, motor control centers, and industrial enclosures. For modern upgrades, this legacy Q-Frame breaker is replaced by the PowerPacT LDL36400U31X.
Line and Load Lugs Included, Line and Load Lugs (AL400LA)
Standards
CSA C22.2 No. 5, Federal Specification W-C-375B/GEN, IEC 60947-2, UL 489
Approval
CSA, HACR, IEC, UL
Temp Rating
-25C to 70C
Construction Features
HACR Rated, Visual Trip Indicator, Push-to-Trip
Product FAQs
6 answers
What are the physical dimensions of the Square D Q4L3400?
This unit-mounted circuit breaker measures 11 inches high, 6 inches wide, and 5.84 inches deep.
Which replacement lug kit is compatible with the Q4L3400?
The standard mechanical lug kit for this breaker is catalog number AL400LA. These terminals accept either one 1 AWG to 600 kcmil conductor or two 1 AWG to 250 kcmil conductors for both aluminum and copper wiring.
Has the Square D Q4L3400 been superseded by a newer model?
Yes. The legacy Q4-frame thermal-magnetic breakers have been replaced by the modern Square D PowerPact L-frame series. When upgrading, you can cross-reference this model to a PowerPact LDL36400U31X, which features a Micrologic electronic trip unit while maintaining the 400A and 25kAIC at 240VAC footprint.
Can I use the Q4L3400 on a 480V or 600V electrical system?
No. The maximum voltage rating for the Q4L3400 is strictly 240VAC. For higher-voltage industrial systems, you must select a breaker rated for 480V or 600V, such as the equivalent PowerPact L-frame replacements.
Does the Q4L3400 include a push-to-trip feature?
Yes, it is equipped with a push-to-trip button on the front face. This allows licensed electricians and panel builders to manually test the mechanical tripping mechanism without exposure to live parts.
Is the Q4L3400 rated for HVAC applications?
Yes, this breaker is HACR rated, making it suitable for heating, air conditioning, and refrigeration group motor applications.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 1 review.