Allen-Bradley 140G-M6X3 800A 3-Pole Molded Case Circuit Breaker

Description

Key Technical Specifications

Rockwell’s current product record confirms that 140G-M6X3 is an 800 A M-frame, 3-pole molded-case circuit-breaker frame, rated at 65 kA at 480 V.

The Rockwell selection documentation gives the broader interrupting-capacity data: 200 kA at 240 VAC, 65 kA at 480 VAC, and 35 kA at 600 VAC under the UL/CSA rating system.

Product Introduction

The Allen-Bradley 140G-M6X3 is an 800 A, 3-pole M-frame molded case circuit breaker frame from Rockwell Automation’s Bulletin 140G family.

An important procurement detail is that 140G-M6X3 is a frame-only catalog number. It is not, by itself, a complete breaker with a selected trip unit. The complete MCCB configuration is built from the appropriate breaker frame and compatible trip unit/accessories. Rockwell describes the 140G product architecture as a combination of frame + trip unit = MCCB.

This distinction matters when replacing an installed breaker. Matching only the 140G frame number does not establish that the existing thermal-magnetic or electronic protection characteristics will be reproduced.

140G-M6X3

Installation & Configuration Guide

Stage 1: Pre-Installation Preparation

⚠️ Safety First: This is high-current power-distribution equipment. Installation, trip-unit selection, SCCR/short-circuit calculations, and commissioning should be performed by qualified electrical personnel under the applicable electrical safety procedure.

Before replacement:

1. Record the complete catalog number 140G-M6X3.
2. Photograph the installed breaker and nameplate.
3. Record the existing trip-unit catalog number.
4. Record the trip-unit settings.
5. Document the 3-phase line and load connections.
6. Record any auxiliary contacts, shunt trip, undervoltage release, or other accessories.
7. Verify the system voltage and available fault current.
8. Confirm that the replacement configuration satisfies the panel’s short-circuit rating.

Stage 2: Existing Breaker Removal

1. De-energize the equipment according to the site’s electrical isolation procedure.
2. Verify absence of voltage using an appropriately rated test instrument.
3. Apply the required lockout/tagout procedure.
4. Record conductor positions before removal.
5. Disconnect line and load conductors according to the applicable installation instructions.
6. Remove installed accessories only if required.
7. Remove the breaker/frame from its mounting arrangement.
8. Inspect bus connections and mounting surfaces.
9. Check for evidence of overheating, arcing, corrosion, or mechanical damage.

Stage 3: Installing the 140G-M6X3

1. Verify the replacement frame is .
2. Confirm the required trip unit separately.
3. Verify the number of poles: 3.
4. Confirm the 800 A frame rating.
5. Install the compatible trip unit according to the manufacturer procedure.
6. Install required accessories.
7. Mount the breaker securely.
8. Reconnect line and load conductors.
9. Verify phase identification.
10. Torque connections to the manufacturer’s specified values.

Procurement/Installation Checklist:

• 140G- frame verified
• 800 A rating confirmed
• 3-pole configuration confirmed
• Trip unit identified
• Trip settings recorded
• Accessories identified
• System voltage verified
• Available fault current checked
• SCCR/interrupting rating verified
• Terminal torque completed

Stage 4: Commissioning & Testing

1. Perform a final mechanical inspection.
2. Verify all electrical connections.
3. Confirm the trip unit is correctly installed and configured.
4. Verify protection settings against the approved coordination study.
5. Perform required insulation/continuity checks.
6. Verify auxiliary and accessory functions where installed.
7. Energize the equipment under the approved commissioning procedure.
8. Monitor phase currents under controlled load.
9. Check for abnormal heating or nuisance tripping.
10. Document the final trip settings and test results.

⚠️ Important: Do not substitute a different trip unit merely because it fits the M-frame. The trip characteristics determine the protection behavior of the completed MCCB.

Frequently Asked Questions

What is Allen-Bradley 140G-?

It is an 800 A, 3-pole M-frame molded case circuit breaker frame from the Allen-Bradley Bulletin 140G family. Rockwell currently lists the catalog number as active.

Is 140G- a complete circuit breaker?

No. It is specified as a frame-only configuration. The appropriate trip unit must be selected separately to create the complete MCCB configuration.

What is the voltage rating?

The Rockwell product record identifies the breaker for applications up to 600 VAC, while the specific interrupting rating depends on the system voltage. The UL/CSA interrupting ratings are 200 kA at 240 VAC, 65 kA at 480 VAC, and 35 kA at 600 VAC.

What is the interrupting rating at 480 VAC?

The specified UL interrupting rating is 65 kA at 480 VAC.

How many poles does 140G- have?

It is a 3-pole frame. Rockwell’s official cut sheet confirms the 3-pole configuration.

What does the “” designation indicate?

For this catalog number, the product is an M-frame, 800 A, 3-pole 140G breaker frame. The corresponding 4-pole version is 140G-M6X4.

Is 140G- still available?

Rockwell Automation currently lists 140G- as Active.

What should I verify before ordering?

For an exact replacement, provide more than the frame number. Verify:

• Existing trip-unit catalog number
• Trip-unit type: thermal-magnetic or electronic
• Long-time/short-time/instantaneous settings, as applicable
• Auxiliary/accessory configuration
• System voltage
• Available short-circuit current
• 3-pole configuration
• Mounting arrangement

This is particularly important because 140G- alone does not define the protection characteristics of the finished breaker.