Quick Hits

Episode 3: Disconnecting Means & Single-Phase Load Restrictions (455.8 – 455.10)

SLIDE 1 (HOOK / COVER)

⚡ NEC Quick Hit: Phase Converter Disconnects & Loads (Part 3) ⚡

Simultaneous ungrounded disconnects, line-of-sight rules, and the golden rule of single-phase loads—let's review Sections 455.8 through 455.10! 👇

SLIDE 2 (DISCONNECTING MEANS REQUIREMENTS)

Isolating the Converter (455.8):

• Location & Accessibility: The disconnecting means must simultaneously open all ungrounded supply conductors, be readily accessible, and be located in sight from the phase converter.

• Ampere/HP Rating: Disconnects must be rated at least 115 percent of maximum input FLC, or follow specific motor current and locked-rotor rules for fixed loads.

SLIDE 3 (SINGLE-PHASE LOADS & TERMINALS)

Protecting Single-Phase Connections:

• No Single-Phase on Manufactured Phase: Where single-phase loads are connected on the load side of a phase converter, they shall not be connected to the manufactured phase.

• Terminal Housings: Phase converters must be equipped with terminal housings complying with Section 430.12.

SLIDE 4 (WRAP-UP)

💡 Apprentice Pro-Tip: Never connect a single-phase 120V or 230V load to the manufactured phase coming off a phase converter—doing so will create severe voltage imbalances and equipment failure!

💬 Save this post for your next phase converter troubleshooting guide!

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