Quick Hits

Episode 2: Motor Branch-Circuit Conductors & Tap Rules (430.22 – 430.29)

SLIDE 1 (HOOK / COVER)

⚡ NEC Quick Hit: Motor Conductors & Tap Rules (Part 2) ⚡ 

Sizing conductors for continuous duty, multi-motor feeders, and specialized tap rules—let's check Sections 430.22 through 430.29! 👇

SLIDE 2 (BRANCH-CIRCUIT CONDUCTOR SIZING)

The 125% Rule and Beyond:

• Single Motor Sizing: Conductors supplying a single motor used in a continuous duty application must have an ampacity of not less than 125% of the motor's full-load current rating (430.22).

• Wound-Rotor Secondary: Conductors for secondary circuits of wound-rotor motors depend on the controller type, ranging from 65% to 125% of rated secondary current.

SLIDE 3 (FEEDERS & TAP CONDUCTORS)

Feeding Multiple Motors and Tap Rules:

• Feeder Sizing (430.24): Feeders supplying multiple motors must be sized at least equal to 125% of the highest full-load current motor, plus the sum of full-load currents of all other motors in the group.

• Motor Circuit Taps (430.28): Taps are permitted without overcurrent protection at the tap point if they are not over 25 feet long, are protected from physical damage, and have an ampacity at least 1/3 that of the feeder conductors.

SLIDE 4 (WRAP-UP)

💡 Apprentice Pro-Tip: When running motor tap conductors under 430.28, make sure the tap wire has an ampacity of at least one-third the rating of the feeder OCPD, and keep it safely enclosed in a raceway!

💬 Save this post for your next multi-motor feeder layout!

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