Square D LHL36300-1021 Molded Case Circuit Breaker
- 300A
- 3 Pole
- Unit Mount
Quantity
Square D LHL36300-1021 - 300A 3 Pole Molded Case Circuit Breaker
New
Quantity
Description
Featuring a factory-installed 120-240VAC shunt trip, the Square D LHL36300-1021 enables remote disconnect capabilities for 300A commercial applications. Designed for legacy L-Frame infrastructure, this unit-mount breaker connects via line and load lugs within compatible Square D enclosures and panelboards. It provides high-interrupting thermal-magnetic protection with a 35 kAIC rating at 480VAC. When upgrading, it is replaced by the LGL36300 with an added shunt trip accessory.Specifications
| Brand | Square D |
|---|---|
| Part Number | LHL36300-1021 |
| Series | LHL |
| Amperage | 300A |
| Poles | 3 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC, 480VAC, 600VAC, 250VDC |
| Phase | 3 |
| 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 | Auxiliary Switch, Undervoltage Release, Alarm Switch, Handle Padlock Attachment |
|---|---|
| Accessories | Shunt Trip (120-240VAC) (Factory Installed), Line and Load Lugs Included |
| Standards | CSA C22.2 No. 5, HACR, IEC 60947-2, NEMA AB 1, UL 489 |
| Approval | CSA, IEC, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, High Interrupting Capacity |
Product FAQs
8 answersWhat does the "-1021" suffix indicate on the LHL36300-1021 catalog number?
The "-1021" suffix designates that this breaker comes equipped with a factory-installed 120-240VAC shunt trip mechanism for remote tripping capabilities.
Which panelboards and switchboards accept the LHL36300-1021?
This legacy L-Frame breaker is compatible with older Square D switchboards, industrial panelboards, and standalone L-Frame enclosures designed for unit-mount (feed-thru) breakers.
What are the wire capacity limits for the standard lugs on this breaker?
The factory line and load lugs can accommodate either a single 1 AWG to 600 kcmil conductor or dual 1 AWG to 250 kcmil conductors per phase. Both aluminum and copper wiring are supported.
What are the maximum fault current interrupting ratings for the LHL36300-1021?
This breaker provides a maximum interrupting capacity of 65kA at 240VAC, 35kA at 480VAC, and 25kA at 600VAC. It is also rated for 50kA at 250VDC.
How is the thermal-magnetic trip unit adjusted on this L-Frame breaker?
The thermal (long-time) protection is fixed at 300A, while the magnetic (instantaneous) trip function is adjustable to allow coordination with downstream devices and specific load inrush currents.
What is the modern replacement for the legacy LHL36300-1021?
Square D has transitioned legacy L-Frame breakers to the PowerPact L-Frame series. Upgrading to a PowerPact equivalent will require a retrofit kit or panel modifications due to different physical dimensions.
Does this breaker plug onto a busbar system?
No, the LHL36300-1021 is a unit-mount breaker. It must be bolted directly to the enclosure or mounting pan and hardwired on both the line and load sides.
What safety function does the factory-installed shunt trip provide?
The 120-240VAC shunt trip allows the breaker to be tripped remotely via an external signal, such as a fire alarm system, emergency stop button, or control relay, instantly disconnecting power to the circuit.
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