Quick Hits

Episode 3: Distribution Points & Site-Isolating Devices (547.40 – 547.43)

SLIDE 1 (HOOK / COVER)

⚡ NEC Quick Hit: Farm Distribution & Site Isolators (Part 3) ⚡

How do you supply multiple livestock buildings safely from a central yard pole? Let's review Sections 547.40 through 547.43! 👇

SLIDE 2 (DISTRIBUTION POINTS & SITE-ISOLATING DEVICES)

Centralized Farm Power Control:

• The Distribution Point: Agricultural buildings or structures for livestock on the same premises must be supplied from a distribution point (often a center yard pole or meter pole).

• Site-Isolating Device: Where two or more buildings are supplied from a distribution point, a pole-mounted site-isolating device must be installed to simultaneously disconnect all ungrounded service conductors.

• Accessibility & Height: The operating handle must be readily accessible, positioned no more than 2.0 m (6 ft 7 in.) above grade or a working platform, and permanently marked.

SLIDE 3 (GROUNDING & DIRECTORIES)

Managing Multiple Feeders:

• Grounding at the Pole: The site-isolating device enclosure and system grounded conductor must be connected to a grounding electrode system at the distribution point.

• Multiple Distribution Points: Where a site is supplied by more than one distribution point, a permanent plaque or directory must be installed at each location denoting all other distribution points and the structures they serve.

SLIDE 4 (WRAP-UP)

💡 Apprentice Pro-Tip: The site-isolating device acts as a master yard switch to kill power to all outbuildings simultaneously, but individual service disconnects and overcurrent protection still reside at each specific building!

💬 Save this post for your next farmyard power distribution design!

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