Skip to main content
Expedited shipping available at checkout

Square D MJA36600 Molded Case Circuit Breaker

  • 600A
  • 3 Pole
  • I-Line
Square D MJA36600
Molded Case Circuit Breaker
Brand Square D
SKU MJA36600
Select Item Condition
Earn 5374 SuperPoints
  • 600A
  • 3 Pole
  • I-Line

Quantity

Bulk Pricing
Send your parts list for a volume quote.
Square D MJA36600 - 600A 3 Pole Molded Case Circuit Breaker

Square D MJA36600 - 600A 3 Pole Molded Case Circuit Breaker

New

$5,374.99 In Stock

Quantity

Similar Items

Description

Engineered for maximum reliability, the MJA36600 is a 600A PowerPacT M-Frame circuit breaker with an ET 1.0 electronic trip unit. This technology delivers highly accurate long-time and instantaneous (LI) protection. Featuring an I-Line connection, it installs easily into compatible Square D panelboards. It also provides a seamless upgrade path for legacy MA and MH frames. Boasting a 65kAIC rating at 480VAC, this unit offers superior current-limiting performance for industrial environments.

Specifications

Key specifications
Brand Square D
Series MJA
Amperage 600A
Poles 3
Mounting Style I-Line
Voltage 240VAC, 480VAC, 600VAC
Phase 3
AIC Rating 100kA @ 240VAC, 65kA @ 480VAC, 25kA @ 600VAC
Fit and installation
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
Protection and operation
Trip Technology Electronic Trip
Trip Function Code LI
Trip Function Long-Time, Instantaneous
Trip Adjustability Fixed Thermal, Adjustable Magnetic
Standards and features
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

9 answers
What types of enclosures or panels accept the MJA36600?

This breaker is designed exclusively for Square D I-Line panelboards and switchboards. It uses a plug-on bracket for the line side and mechanical lugs on the load side.

Can the MJA36600 replace older Square D 600A breakers?

Yes. The PowerPacT M-frame serves as a direct upgrade for legacy MA and MH frame breakers, such as the MA36600 and MH36600, fitting into the exact same I-Line panel space.

Does the MJA36600 allow for field adjustments?

Yes. While the long-time thermal protection is fixed at 600A, the ET 1.0 electronic trip unit features an adjustable instantaneous magnetic trip dial, which can be set between 1200A and 6000A.

Is the MJA36600 rated for 100% continuous duty?

No. This breaker carries a standard 80% continuous current rating, meaning continuous loads should not exceed 480A for three hours or more.

What size wire can be installed in the load lugs of this breaker?

The factory-installed AL800M23K load lugs accept up to three aluminum or copper conductors per phase, ranging from 3/0 AWG to 500 kcmil.

What is the required tightening torque for the load lugs?

The AL800M23K terminal lugs must be torqued to 442 inch-pounds (50 Nm) to ensure secure electrical connections and prevent thermal issues.

Can the MJA36600 be reverse fed?

No. Because it utilizes a specific I-Line plug-on jaw connection intended strictly for the line side panel bus, this breaker cannot be reverse fed.

What is the phase connection configuration for this breaker?

The MJA36600 features standard ABC phase connections on the line side plug-on jaw, which aligns with standard bus arrangements in I-Line distribution panels.

Does this breaker include a mechanism for mechanical testing?

Yes. The front cover includes a push-to-trip button, allowing electricians to manually open the contacts and verify the mechanical operation of the trip unit prior to servicing.

SuperClub

Join free. Get 500 SuperPoints.

Earn points on eligible purchases and redeem them at checkout.

100 SuperPoints = $1 off.

Warranties

60-Day Warranty

Your purchase includes 60 days of SuperBreakers warranty coverage.

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.

Read our full shipping policy

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.