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Square D MJL36300 Molded Case Circuit Breaker
- 300A
- 3 Pole
- Unit Mount
Square D
MJL36300
Molded Case Circuit Breaker
Brand
Square D
SKU
MJL36300
Quantity
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Square D MJL36300 - 300A 3 Pole Molded Case Circuit Breaker
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Description
Built for robust power distribution, the Square D MJL36300 is a 300A, 3-pole PowerPacT M-Frame molded case circuit breaker. It is designed for use in commercial and industrial facilities. This unit-mount breaker installs into Square D switchboards, motor control centers, and industrial control panels. It replaces older MA36300 and MH36300 models. Delivering 65kAIC at 480VAC, it utilizes an ET 1.0 electronic trip unit with long-time and instantaneous (LI) functions for enhanced coordination.Specifications
| Brand | Square D |
|---|---|
| Series | MJL |
| Amperage | 300A |
| Poles | 3 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC, 480VAC, 600VAC |
| Phase | 3 |
| AIC Rating | 100kA @ 240VAC, 65kA @ 480VAC, 25kA @ 600VAC |
| Frame Type | MJL |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D Switchboards, Motor Control Centers, Industrial Control Panels |
| Wire Gauge | (3) 3/0 AWG - 500 kcmil (Al/Cu) |
| Max Wire | 500 kcmil |
| Min Wire | 3/0 AWG |
| Trip Technology | Electronic Trip |
|---|---|
| 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, Handle Padlock Attachment |
|---|---|
| Accessories | Line and Load Lugs Included |
| Standards | CSA C22.2 No. 5, IEC 60947-2, NEMA AB 1, UL 489 |
| Approval | CE, CSA, IEC, NOM, UL |
| Temp Rating | -25C to 70C |
| Construction Features | HACR Rated, Current Limiting, 80% Rated, Mercury Free, PVC Free, Non-Interchangeable Trip |
Product FAQs
8 answersWhat is the recommended tightening torque for the lugs on the Square D MJL36300 circuit breaker?
The factory lugs for the MJL36300 require a tightening torque of 442.5 lb-in (50 N.m) for 3/0 AWG to 500 kcmil aluminum or copper wire.
Can I replace the electronic trip unit in the MJL36300 breaker?
No, the MJL36300 features a built-in ET 1.0 electronic trip unit that is factory sealed and cannot be field-replaced.
Is the trip unit on the MJL36300 adjustable?
The breaker has a fixed long-time (overload) setting of 300A, but includes an adjustable instantaneous (magnetic) trip function that can typically be set between 600A and 3000A.
What are the physical dimensions of the MJL36300 M-Frame breaker?
The MJL36300 measures 12.86 inches in height, 8.27 inches in width, and 5.77 inches in depth. It shares the same mounting dimensions and door cut-out as PowerPact P-frame circuit breakers.
What types of electrical equipment are compatible with the MJL36300?
The MJL36300 unit-mount breaker is designed for installation in Square D switchboards, motor control centers, and industrial control panels for heavy-duty feeder protection.
Does the MJL36300 come equipped with line and load side lugs?
Yes, as a feed-thru, unit-mount circuit breaker, the MJL36300 comes standard with mechanical lugs on both the line and load ends.
Is the MJL36300 rated for 100 percent continuous current?
No, this breaker is standard rated for 80 percent continuous current.
Can the PowerPact M-Frame MJL36300 be used to upgrade older Square D circuit breakers?
Yes, PowerPact M-Frame breakers are designed to replace traditional Square D MA and MH frame circuit breakers, offering improved electronic trip accuracy in a more compact footprint.
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