Square D LHL26400MB Molded Case Circuit Breaker
- 400A
- 2 Pole
- Unit Mount
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Square D LHL26400MB - 400A 2 Pole Molded Case Circuit Breaker
New
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Description
Designed with a specialized short handle (MB suffix), the Square D LHL26400MB provides 400A of 2-pole circuit protection. This unique actuator allows panel doors to close properly in space-constrained commercial and industrial setups. The unit mount breaker installs into Square D L-Frame enclosures, switchboards, and panelboards. It serves as a direct substitute for the standard LHL26400 when clearance is an issue. It features thermal-magnetic LI trip functions and a 65kAIC rating at 240VAC.Specifications
| Brand | Square D |
|---|---|
| Part Number | LHL26400MB |
| Series | LHL |
| Amperage | 400A |
| Poles | 2 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC, 480VAC, 600VAC, 250VDC |
| Phase | 1 |
| AIC Rating | 65kA @ 240VAC, 35kA @ 480VAC, 25kA @ 600VAC, 50kA @ 250VDC |
| Frame Type | LHL |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D L-Frame Enclosures, Switchboards, Panelboards |
| 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 |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Adjustable Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Undervoltage Release, Alarm Switch |
|---|---|
| Accessories | Lugs (AL400LA) |
| Standards | CSA C22.2 No. 5, HACR Rated, IEC 60947-2, UL 489 |
| Approval | CSA, IEC, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, High Interrupting Capacity, Short Handle |
Product FAQs
7 answersWhat are the acceptable wire sizes and configurations for the LHL26400MB lugs?
The standard lugs accommodate either a single 1 AWG to 600 kcmil conductor or dual 1 AWG to 250 kcmil conductors per phase. Both aluminum and copper wires are supported.
Can the LHL26400MB be used in Square D I-Line panelboards?
No. The LHL26400MB is a unit-mount circuit breaker equipped with feed-thru lugs on both ends. It is designed for standard panelboards, switchboards, and L-Frame enclosures, rather than I-Line plug-on applications.
How does the adjustable magnetic trip work on the LHL26400MB?
While the thermal overload protection is fixed at 400 amps, the magnetic instantaneous trip function is adjustable. This allows electricians to fine-tune the short-circuit response threshold to coordinate with downstream breakers and prevent nuisance tripping.
Is there a newer alternative to the legacy LHL26400MB?
Yes. The LHL26400MB is a legacy Square D component. During modern system upgrades, it is frequently replaced by the newer PowerPact L-Frame series, such as the LGL26400, though physical footprint and mounting differences must be verified before retrofitting.
Does the LHL26400MB provide equipment ground fault protection?
No. The LI trip function code indicates it provides Long-Time (thermal) and Instantaneous (magnetic) protection only. It does not include integral ground fault (G) protection, which would require an LSIG or LIG trip unit.
Is the LHL26400MB suitable for high-fault commercial systems?
Yes, it is a high-interrupting capacity breaker. It can safely clear fault currents up to 65,000 amps at 240V AC or 35,000 amps at 480V AC, making it suitable for commercial and industrial systems with high available fault currents.
Can the LHL26400MB be applied in DC circuits?
Yes, it is rated for up to 250V DC with a 50kA interrupting capacity. When installing in DC systems, ensure the wiring and enclosure are properly rated for direct current applications.
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