OVERVIEW

Official designation: Allen-Bradley 140U-D6D3-C20 (Bulletin 140U, Molded Case Circuit Breaker)

Role/Application: D-Frame, 3-pole MCCB rated 20 Amperes. It provides fixed thermal and adjustable magnetic overcurrent protection for branch and feeder circuits in industrial control systems.

KEY SPECS SUMMARY

Power: 600 Volts AC maximum

Interfaces / Ports: Line and load terminals

Indicators: Trip status flag

Operating Temp: Minus 25 to plus 60 degrees C

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

Limit: Interrupting rating 65 kA at 480 Volts AC

Lifecycle: Discontinued, replacement 140G

FREQUENTLY ASKED QUESTIONS

Technical Specifications:

Q: What is the adjustable magnetic trip setting range for the 20 Amp D-Frame MCCB?

A: The magnetic trip setting is adjustable from 15 times to 20 times the rated current (300 to 400 Amperes).

Wiring & Installation:

Q: What is the recommended wire gauge range for connecting to the breaker terminals?

A: The recommended wire range is #14 to #10 AWG, copper only.

Troubleshooting & Compatibility:

Q: Is the 20 Amp 140U-D6D3-C20 model 100 percent rated for continuous duty applications?

A: Breakers up to 15 Amperes are 100 percent rated; this 20 Amp model is typically 80 percent rated.

Replacement & Upgrades:

Q: What is the current Allen-Bradley series recommended as a modern replacement for the Bulletin 140U MCCB line?

A: The recommended successor is the Allen-Bradley Bulletin 140G series Molded Case Circuit Breakers.