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📱 EPISODE 5 — Article 245 (Part 5)

Load-Interrupter Switches

SLIDE 1 — Load Interrupters Basics (245.21(E))
🔀 LOAD-INTERRUPTER SWITCHES

These are permitted IF suitable fuses or breakers are used alongside them to interrupt available fault currents. When combined, they must be electrically coordinated to safely handle closing, carrying, AND interrupting all possible currents up to the assigned max short-circuit rating.

⚠️ Multiple switches with interconnected load terminals (for alternate supply connections)? Each switch needs a warning sign about the multiple sources, per 110.21.

SLIDE 2 — Ratings & Identification
📊 RATING REQUIREMENTS

🔹 Continuous current rating ≥ max continuous current at that point
🔹 Max voltage rating ≥ max circuit voltage
🔹 Nameplate must show: manufacturer type/designation, continuous current rating, interrupting current rating, fault closing rating, max voltage rating

That's more nameplate data than standard cutouts — load interrupters are doing more work, so they carry more documentation.

SLIDE 3 — Switching & Supply Terminal Rules
🎛️ OPERATION REQUIREMENTS

✅ Operated from a location where the operator isn't exposed to energized parts
✅ Must open ALL ungrounded conductors simultaneously in ONE operation
✅ Must be lockable in the open position
✅ Metal-enclosed switches must be operable from OUTSIDE the enclosure

⚡ Stored-energy operators can stay "uncharged" after closing — IF a single handle movement both charges the operator AND opens the switch.

🔌 Supply terminals on fused interrupter switches go at the TOP of the enclosure — or if located elsewhere, barriers are required to stop accidental contact or dropped tools/fuses from reaching energized parts.

SLIDE 4 — Exam Question + CTA
🧠 TEST YOURSELF

Q: Per 245.21(E)(4), how must the switching mechanism of a load-interrupter switch operate the ungrounded conductors?

A) One conductor at a time, in sequence
B) All ungrounded conductors simultaneously with one operation
C) Only two of three phases need to open together
D) Manually, conductor by conductor

(Drop your answer 👇)

Next up: Feeder & branch-circuit overcurrent protection — the final stretch of Article 245! FOLLOW ⚡ #JoshTheSparky #NEC2026 #ElectricianLife

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