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Square D MGA36300 Molded Case Circuit Breaker
- 300A
- 3 Pole
- I-Line
Square D
MGA36300
Molded Case Circuit Breaker
Brand
Square D
SKU
MGA36300
Quantity
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Square D MGA36300 - 300A 3 Pole Molded Case Circuit Breaker
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Description
Engineered for commercial power systems, the Square D MGA36300 is a 300A, three-pole molded case circuit breaker. As part of the PowerPacT M-Frame family, it incorporates an ET 1.0 electronic trip unit to provide highly accurate long-time and instantaneous (LI) protection. Designed for quick installation, this breaker plugs into Square D I-Line panelboards. It serves as an exact replacement for older MA36300 breakers. With a 35 kAIC rating at 480VAC, it handles high fault currents safely.Specifications
| Brand | Square D |
|---|---|
| Series | MGA |
| Amperage | 300A |
| Poles | 3 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 480VAC, 600VAC |
| Phase | 3 |
| AIC Rating | 65kA @ 240VAC, 35kA @ 480VAC, 18kA @ 600VAC |
| Frame Type | M |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D I-Line Panelboards, Switchboards |
| Wire Gauge | 3x 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 |
|---|---|
| Accessories | Lugs (Load Side) |
| 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, Mercury Free, PVC Free, Push-to-Trip |
Product FAQs
8 answersWhat equipment is the MGA36300 designed to fit?
This breaker installs in Square D I-Line panelboards and switchboards. It uses a plug-on line side connection and features mechanical lugs on the load side.
Can the MGA36300 replace older MA-frame breakers?
Yes, the PowerPacT M-frame MGA36300 is a direct replacement for the legacy MA36300 circuit breaker. It features a smaller footprint but uses the same I-Line mounting and door cut-out.
What is the recommended tightening torque for the load side lugs?
The standard lugs on this M-frame breaker should be torqued to 442.5 lbf-in (50 N.m) when using 3/0 AWG to 500 kcmil aluminum or copper wire.
What does the "G" in the MGA36300 catalog number signify?
The "G" indicates the interrupting rating tier for this PowerPacT breaker. It provides 65kA at 240V, 35kA at 480V, and 18kA at 600V.
What type of trip unit is installed in the MGA36300?
It features a built-in ET 1.0 electronic trip unit. This provides fixed long-time and adjustable instantaneous (LI) protection, offering better accuracy than standard thermal-magnetic trip units.
What is the instantaneous trip adjustment range for the MGA36300?
The ET 1.0 trip unit features an adjustable instantaneous (magnetic) trip setting that ranges from 2 to 10 times the nominal ampere rating, which equals 600A to 3000A for this 300A breaker.
What is the difference between the MGA36300 and MJA36300?
The difference is the interrupting rating. The MGA36300 has a "G" rating (35kA at 480V), while the MJA36300 has a higher "J" rating (65kA at 480V). Both are 300A, 3-pole I-Line breakers.
Can the ET 1.0 trip unit in this breaker be replaced in the field?
No, the ET 1.0 electronic trip unit is factory-installed and cannot be field replaced. It also does not allow adjustment of the long-time trip point setting.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 1 review.
Total 5 star reviews: 1 Total 4 star reviews: 0 Total 3 star reviews: 0 Total 2 star reviews: 0 Total 1 star reviews: 0
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Rating
1 review
- JBJosh B.Verified BuyerReviewingSquare D MGA36800 - 800A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars8/11/26Breaker Arrive quickly and as described
Breaker was what I needed in a pinch. Quick delivery and got customer back going.