Free Shipping Over $99
Square D MH36300 Molded Case Circuit Breaker
- 300A
- 3 Pole
- I-Line
Square D
MH36300
Molded Case Circuit Breaker
Brand
Square D
SKU
MH36300
Quantity
Shop with Confidence
Add an extra year of protection in your cart.
Square D MH36300 - 300A 3 Pole Molded Case Circuit Breaker
New
Quantity
Quantity
Square D MH36300 - 300A 3 Pole Molded Case Circuit Breaker
New
Quantity
| Brand | Square D |
|---|---|
| Part Number | MH36300-R |
| Series | MH |
| Amperage | 300A |
| Poles | 3 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 480Y/277VAC, 480VAC, 600Y/347VAC, 600VAC, 250VDC |
| Phase | 3 |
| AIC Rating | 65kA @ 240VAC, 65kA @ 480Y/277VAC, 65kA @ 480VAC, 25kA @ 600Y/347VAC, 25kA @ 600VAC, 14kA @ 250VDC |
| Frame Type | MH |
|---|---|
| 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 | 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, Padlock Attachment |
|---|---|
| Accessories | Lugs |
| Standards | CSA C22.2 No. 5, IEC 60947-2, NEMA AB 1, UL 489 |
| Approval | CE, CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, High Interrupting Capacity, Visual Trip Indicator, Common Trip, Trip-Free Mechanism |
Quantity
Square D MH36300 - 300A 3 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
| Brand | Square D |
|---|---|
| Part Number | MH36300-R |
| Series | MH |
| Amperage | 300A |
| Poles | 3 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 480Y/277VAC, 480VAC, 600Y/347VAC, 600VAC, 250VDC |
| Phase | 3 |
| AIC Rating | 65kA @ 240VAC, 65kA @ 480Y/277VAC, 65kA @ 480VAC, 25kA @ 600Y/347VAC, 25kA @ 600VAC, 14kA @ 250VDC |
| Frame Type | MH |
|---|---|
| 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 | 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, Padlock Attachment |
|---|---|
| Accessories | Lugs |
| Standards | CSA C22.2 No. 5, IEC 60947-2, NEMA AB 1, UL 489 |
| Approval | CE, CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, High Interrupting Capacity, Visual Trip Indicator, Common Trip, Trip-Free Mechanism |
Similar Items
400A 3 Pole Molded Case Circuit Breaker
450A 3 Pole Molded Case Circuit Breaker
500A 3 Pole Molded Case Circuit Breaker
Description
Designed for rapid installation, this 300A molded case circuit breaker delivers reliable long-time and instantaneous protection. The unit features an I-Line mounting style, allowing it to plug securely into compatible Square D switchboards. For modernizing older infrastructure, this M-Frame breaker is often replaced by the newer PowerPact MJA36300 series. Rated for 65kA at 480VAC, it incorporates a Visi-Trip indicator to help maintenance personnel quickly identify faulted circuits.Specifications
| Brand | Square D |
|---|---|
| Part Number | MH36300-R |
| Series | MH |
| Amperage | 300A |
| Poles | 3 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 480Y/277VAC, 480VAC, 600Y/347VAC, 600VAC, 250VDC |
| Phase | 3 |
| AIC Rating | 65kA @ 240VAC, 65kA @ 480Y/277VAC, 65kA @ 480VAC, 25kA @ 600Y/347VAC, 25kA @ 600VAC, 14kA @ 250VDC |
| Frame Type | MH |
|---|---|
| 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 | 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, Padlock Attachment |
|---|---|
| Accessories | Lugs |
| Standards | CSA C22.2 No. 5, IEC 60947-2, NEMA AB 1, UL 489 |
| Approval | CE, CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, High Interrupting Capacity, Visual Trip Indicator, Common Trip, Trip-Free Mechanism |
Product FAQs
6 answersHow much mounting space does the MH36300 require in an I-Line panelboard?
This M-frame circuit breaker requires 9 inches of vertical mounting space in a compatible Square D I-Line panelboard or switchboard.
Can the MH36300 replace older Square D M-frame breakers?
Yes, the MH36300 is a direct I-Line replacement for legacy Square D M-frame breakers, including the MAL36300 and MHL36300 catalog numbers.
What is the modern PowerPact equivalent for the MH36300?
When modernizing older infrastructure, this legacy M-frame breaker is typically replaced by the newer PowerPact M-frame series, such as the MJA36300, depending on your specific interrupting rating requirements.
What is the advantage of the adjustable magnetic trip on the MH36300?
The adjustable magnetic trip allows electricians to tune the instantaneous short-circuit response. This flexibility is useful for preventing nuisance tripping caused by high inrush currents, such as when starting large motors or energizing transformers.
What wire sizes are accepted by the lugs on this breaker?
The factory-installed lugs accommodate 3/0 AWG to 500 kcmil aluminum or copper conductors. Ensure all wire binding screws are torqued to the manufacturer specifications printed on the breaker faceplate.
What is the proper procedure for installing this I-Line breaker?
Always de-energize the panelboard before installation. Align the plug-on jaws with the busbars, push the breaker firmly into place, and secure it using the built-in mounting bracket and retaining screw to ensure a safe, reliable connection.
SuperClub
Join free. Get 500 SuperPoints.
Earn points on eligible purchases and redeem them at checkout.
100 SuperPoints = $1 off.
Warranties
Add an extra year of protection
60-Day Warranty
Your purchase includes 60 days of SuperBreakers warranty coverage.
Add a 1-year warranty extension in your cart.
Get a Quote
Don’t see what you’re looking for?
We source obsolete and hard-to-find parts every day.
Shipping
Free Shipping Policy
Parcel shipments with item value over $99 qualify for free economy shipping within the continental US. Please call to confirm special handling instructions. We do not charge a handling fee or require a minimum amount on any order. SuperBreakers does not ship on customer accounts.
Same Day Shipping
We strive to ship out your items the same day the order is placed. In rare circumstances SuperBreakers may reserve up to 5 business days to consolidate orders for complete shipment.
Expedited Shipments
Orders being shipped via Next Day Air, 2 Day Shipping or 3 Day Shipping must be received by 3 PM EST to guarantee same-day shipments. Expedited orders only ship on normal business days. Shipments will NOT be sent out on Saturdays and Sundays.
International Shipping
All International orders require a $1,000 minimum order threshold. Due to the special nature of these shipments, we require that these be placed with a SuperBreakers representative. Additional shipping and instructions will apply. All International Orders are Non-Cancel and Non-Refundable.
Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 4 reviews.
Total 5 star reviews: 4 Total 4 star reviews: 0 Total 3 star reviews: 0 Total 2 star reviews: 0 Total 1 star reviews: 0
Search
Rating
4 reviews
- DLDeanna L.Verified BuyerReviewingSquare D MH36800 - 800A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars8/11/26Square D MH36800 - 800A 3 Pole Molded Case Circuit Breaker
Another satisfied customer.
- SBSteve B.Verified BuyerReviewingSquare D MH36600 - 600A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars1/23/26Square MH36600
Breaker was as advertised excellent condition
- SAStewart A.ReviewingSquare D MH38 Panel Board EnclosureI recommend this productRated 5 out of 5 stars3/25/19not at local supply
got what I needed, because it was not available at my local supply house.
- WWWilliam W.ReviewingSquare D MH32 Panel Board EnclosureI recommend this productRated 5 out of 5 stars7/1/18INSIDE THE BOX
Great Buy ! Shipped on time. No Damage. Just what we ordered Thanks