Indoor switchgear MUST be stored in a location that protects it from

• A. Dust
• B. Heat
• C. Vibration
• D. Moisture

Answer: (D)

Moisture is the main danger to stored indoor switchgear because water affects insulation and metal parts, which are critical for safe operation. When humidity is high or condensation occurs, insulation materials can absorb moisture, reducing dielectric strength and increasing the risk of insulation failure. Moisture also accelerates corrosion of metal components and contacts, and can promote tracking or arcing on energized surfaces once power is applied. Keeping switchgear in a dry, well-controlled environment helps preserve insulation integrity, prevent rust, and maintain reliable performance.

Dust, heat, and vibration are concerns too, but they don’t undermine insulation and corrosion protection as directly or severely as moisture does. Dust can be mitigated with cleaning and enclosure sealing, heat is managed with temperature control, and vibration is less of an issue in a stored, static condition.