Electrical Equipment Maintenance & Inspection Flashcards

What is the primary reason that electrical maintenance intervals should be shortened for equipment operating in high-humidity or corrosive environments?

Answer: Moisture and contaminants accelerate insulation degradation and corrosion of connections faster than in clean, dry environments

Moisture and airborne contaminants accelerate insulation breakdown and oxidation of electrical connections, increasing failure risk between standard maintenance cycles.

During inspection of a low-voltage switchboard, a technician observes white, powdery deposits on aluminum bus connections. What does this indicate and what action is required?

Answer: Aluminum oxide corrosion indicating poor connection integrity; clean, apply joint compound, and re-torque to specification

White powder on aluminum bus connections is aluminum oxide, a poor conductor that increases resistance and generates heat; the joint must be cleaned, re-treated, and torqued to spec.

When is it permissible to use a tagout-only procedure instead of a lockout procedure for hazardous energy control?

Answer: Only when the equipment's design prevents attachment of a lockout device

OSHA 29 CFR 1910.147 permits tagout-only when the equipment cannot physically accept a lockout device, but additional protective measures must compensate for the reduced protection.

A facility's preventive maintenance program for electrical equipment is described as 'condition-based.' What distinguishes this approach from a purely time-based program?

Answer: Maintenance intervals are adjusted based on actual equipment condition data such as IR scans and oil analysis results

Condition-based maintenance uses real-time diagnostic data (IR thermography, DGA, vibration analysis) to schedule maintenance when equipment condition warrants it, optimizing resources.

What torque value specification must be followed when re-terminating conductors on electrical equipment lugs after maintenance?

Answer: The manufacturer's specified torque value for that specific terminal or lug

Lug and terminal torque specifications are manufacturer-specific; over- or under-torquing can damage the terminal or create a loose connection, so the nameplate or documentation value must be followed.

An infrared survey of an electrical panel reveals a temperature difference of 35°C between a breaker and its identical neighbor under similar load. According to NETA acceptance criteria, how should this finding be classified?

Answer: Priority 1 (critical; schedule repair immediately, consider removing from service)

Per NETA/NFPA 70B, a ΔT of 35°C above a reference is classified as a critical Priority 1 condition requiring immediate corrective action and possible removal from service.

Which document serves as the primary reference for establishing a recommended maintenance program for electrical equipment in commercial and industrial facilities?

Answer: NFPA 70B (Recommended Practice for Electrical Equipment Maintenance)

NFPA 70B is the dedicated recommended practice document that provides maintenance intervals, test methods, and acceptance criteria for electrical equipment in facilities.