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Square D MJA36400 Molded Case Circuit Breaker
- 400A
- 3 Pole
- I-Line
Square D
MJA36400
Molded Case Circuit Breaker
Brand
Square D
SKU
MJA36400
Quantity
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Square D MJA36400 - 400A 3 Pole Molded Case Circuit Breaker
New
Quantity
Quantity
Square D MJA36400 - 400A 3 Pole Molded Case Circuit Breaker
New
Quantity
| Brand | Square D |
|---|---|
| Series | MJA |
| Amperage | 400A |
| Poles | 3 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 480VAC, 600VAC |
| Phase | 3 |
| AIC Rating | 100kA @ 240VAC, 65kA @ 480VAC, 25kA @ 600VAC |
| Frame Type | MJA |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D I-Line Panelboards, Switchboards |
| 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, Padlock Attachment |
|---|---|
| Accessories | Lugs (AL800M23K) |
| Standards | CSA C22.2 No. 5, HACR, IEC 60947-2, NEMA AB 1, NOM-003-SCFI-2000, UL 489 |
| Approval | CE, CSA, IEC, NOM, UL |
| Temp Rating | -25C to 70C |
| Construction Features | HACR Rated, Current Limiting, Mercury Free, PVC Free, Push-to-Trip, 80% Rated |
Quantity
Square D MJA36400 - 400A 3 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
| Brand | Square D |
|---|---|
| Series | MJA |
| Amperage | 400A |
| Poles | 3 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 480VAC, 600VAC |
| Phase | 3 |
| AIC Rating | 100kA @ 240VAC, 65kA @ 480VAC, 25kA @ 600VAC |
| Frame Type | MJA |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D I-Line Panelboards, Switchboards |
| 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, Padlock Attachment |
|---|---|
| Accessories | Lugs (AL800M23K) |
| Standards | CSA C22.2 No. 5, HACR, IEC 60947-2, NEMA AB 1, NOM-003-SCFI-2000, UL 489 |
| Approval | CE, CSA, IEC, NOM, UL |
| Temp Rating | -25C to 70C |
| Construction Features | HACR Rated, Current Limiting, Mercury Free, PVC Free, Push-to-Trip, 80% Rated |
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Description
Engineered for robust power distribution, the Square D MJA36400 is a 3-pole, 400A electronic trip MCCB from the PowerPacT M-Frame series. This unit utilizes an I-Line mounting configuration for use with Square D I-Line panelboards and switchboards. It provides an ideal upgrade path for replacing legacy MA and MH frame breakers. The integrated ET 1.0 trip unit offers adjustable magnetic and fixed thermal settings (LI) to optimize coordination. It delivers a 65kAIC rating at 480VAC.Specifications
| Brand | Square D |
|---|---|
| Series | MJA |
| Amperage | 400A |
| Poles | 3 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 480VAC, 600VAC |
| Phase | 3 |
| AIC Rating | 100kA @ 240VAC, 65kA @ 480VAC, 25kA @ 600VAC |
| Frame Type | MJA |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D I-Line Panelboards, Switchboards |
| 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, Padlock Attachment |
|---|---|
| Accessories | Lugs (AL800M23K) |
| Standards | CSA C22.2 No. 5, HACR, IEC 60947-2, NEMA AB 1, NOM-003-SCFI-2000, UL 489 |
| Approval | CE, CSA, IEC, NOM, UL |
| Temp Rating | -25C to 70C |
| Construction Features | HACR Rated, Current Limiting, Mercury Free, PVC Free, Push-to-Trip, 80% Rated |
Product FAQs
6 answersWhat type of line and load connections does this breaker have?
The line side features I-Line plug-in jaws that mount directly onto the bus panel. The load side is equipped with AL800M23K mechanical lugs that accept three 3/0 AWG to 500 kcmil aluminum or copper conductors.
Can the MJA36400 replace older Square D MA or MH frame circuit breakers?
Yes. This PowerPacT M-Frame circuit breaker provides a direct upgrade path for replacing 400-amp legacy MA and MH frame I-Line breakers, such as the MH36400.
What enclosures are compatible with this circuit breaker?
This unit requires an I-Line mounting configuration and is designed exclusively for use in Square D I-Line panelboards and switchboards. The specific panel must have adequate bus capacity to safely support a 400-amp plug-in breaker.
Are the trip settings adjustable on the ET 1.0 electronic trip unit?
The long-time continuous current pickup is fixed at 400 amps, while the instantaneous magnetic trip function is adjustable. This allows installers to fine-tune the short circuit protection from 800A to 4000A to optimize system coordination.
What is the recommended tightening torque for the load lugs?
The factory-installed AL800M23K mechanical lugs require a tightening torque of 442.5 lbf-in (50 N.m) for 3/0 AWG to 500 kcmil wire. Always verify exact torque values on the physical circuit breaker label before finalizing installation.
Is this electronic trip circuit breaker safe for use on DC circuits?
No. The MJA36400 utilizes a basic ET 1.0 electronic trip unit that requires alternating current to operate properly. For safety and proper protection, it must only be used on AC distribution systems up to 600VAC.
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