Quick Hits

Episode 3: Switchgear, Substations & Mobile Equipment Safeguards (495.30 – 495.66)

SLIDE 1 (HOOK / COVER)

⚡ NEC Quick Hit: Switchgear, Substations & Mobile Gear (Part 3) ⚡

High-voltage compartment barriers, "KEEP OUT" signage, fused interrupter rules, and portable equipment enclosures—let's review Parts III and IV! 👇

SLIDE 2 (SWITCHGEAR ACCESSIBILITY & FUSED INTERRUPTERS)

Guarding Compartments and Fuses:

• Locked Doors & Signs: Doors providing access to high-voltage parts must be locked and marked with permanent signs reading DANGER — HIGH VOLTAGE — KEEP OUT.

• Fused Interrupter Rules: Supply terminals of fused interrupter switches require top placement or barriers to prevent accidental contact, and switches must be lockable open per Section 110.25.

• Service Ground Bus: High-voltage service switchgear must include an extended ground bus for cable shields and temporary protective grounding.

SLIDE 3 (MOBILE & PORTABLE HIGH-VOLTAGE EQUIPMENT)

Enclosures on Skids and Trailers:

• Grounded Metal Cabinets: Energized switching parts on mobile equipment (like shovels and draglines) must be enclosed in grounded, locked metal cabinets marked DANGER — HIGH VOLTAGE — KEEP OUT.

• External Resetting: Circuit breakers must have operating mechanisms projecting through the enclosure so units can be reset without opening locked high-voltage doors.

SLIDE 4 (WRAP-UP)

💡 Apprentice Pro-Tip: On mobile high-voltage skids and trailers, ensure your circuit breaker operating handles project through the locked cabinet doors so operators can safely reset them without exposing live parts!

💬 Save this post for your next industrial mining or mobile equipment setup!

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