OVERVIEW

Official designation: Allen-Bradley 140U-I0C3-C40 (Bulletin 140U, Molded Case Circuit Breaker)

Role/Application: I-Frame, 3-pole MCCB rated for 40 Amperes. It provides motor short-circuit protection using a fixed, non-adjustable magnetic trip, suitable for coordination with NEMA starters.

KEY SPECS SUMMARY

Power: 480 Volts AC maximum

Interfaces / Ports: Line and load terminals

Indicators: Trip status flag

Operating Temp: Minus 25 to plus 70 degrees C

Platform / Compatibility: I-Frame; UL 489, CSA, CE

Limit: Magnetic trip 500–1000 Amps

Lifecycle: Discontinued, replacement 140G

FREQUENTLY ASKED QUESTIONS

Technical Specifications:

Q: What is the short circuit interrupting capacity (kAIC) for the 140U-I0C3-C40 at 480 Volts AC?

A: The typical interrupting capacity for the I-Frame model is 25 kA at 480V AC.

Wiring & Installation:

Q: What is the required conductor temperature rating for wiring to the 140U I-Frame terminals?

A: Terminals require the use of 75 degrees C rated copper wire only for connections.

Troubleshooting & Compatibility:

Q: How does the fixed magnetic trip setting of this MCCB relate to NEMA motor starter sizes?

A: The trip range of 500–1000 A is commonly used for NEMA motor starter Sizes 1 or 2.

Replacement & Upgrades:

Q: What is the current recommended series from Allen-Bradley to replace the discontinued Bulletin 140U circuit breakers?

A: The current replacement is generally the Allen-Bradley Bulletin 140G series MCCB.