WALMART MAINTENANCE Electrical Systems 3 — Questions and Answers
Question 1: What does GFCI stand for in electrical safety?
- Ground Fault Circuit Interrupter (Correct answer)
- General Fuse Circuit Indicator
- Ground Frequency Control Interface
- General Fault Current Isolator
Correct answer: Ground Fault Circuit Interrupter
GFCI stands for Ground Fault Circuit Interrupter, a device that protects against electrical shock by detecting ground faults.
Question 2: In a 3-phase electrical system used in large retail facilities, what is the phase angle between each phase?
- 90 degrees
- 120 degrees (Correct answer)
- 180 degrees
- 60 degrees
Correct answer: 120 degrees
In a 3-phase system, each phase is separated by 120 degrees, providing balanced power distribution.
Question 3: When checking a motor's insulation resistance with a megohmmeter, what reading generally indicates acceptable insulation?
- Less than 1 megohm
- At least 1 megohm (Correct answer)
- Exactly 0 ohms
- Between 100 and 500 ohms
Correct answer: At least 1 megohm
Acceptable motor insulation resistance is typically at least 1 megohm, with higher values indicating better insulation condition.
Question 4: What color is the grounding conductor in standard US electrical wiring?
- White
- Black
- Green or bare copper (Correct answer)
- Red
Correct answer: Green or bare copper
The grounding conductor in US wiring is green or bare copper, distinguishing it from neutral (white) and hot (black/red) conductors.
Question 5: Which device is used to measure electrical current without breaking the circuit?
- Voltmeter
- Ohmmeter
- Clamp meter (Correct answer)
- Wattmeter
Correct answer: Clamp meter
A clamp meter measures current by clamping around a conductor, using the magnetic field to calculate amperage without breaking the circuit.
Question 6: In Walmart's electrical maintenance, what is the correct procedure before working on a lighting circuit?
- Turn off the light switch only
- Apply lockout/tagout and verify zero energy state (Correct answer)
- Wear rubber gloves and proceed
- Post a warning sign and work quickly
Correct answer: Apply lockout/tagout and verify zero energy state
Lockout/tagout (LOTO) must be applied and zero energy verified before any electrical work, per OSHA requirements.
Question 7: What is the purpose of a neutral conductor in an electrical circuit?
- Carry fault current to ground
- Provide the return path for current (Correct answer)
- Protect against overvoltage
- Limit current flow in the circuit
Correct answer: Provide the return path for current
The neutral conductor provides the return path for current back to the source, completing the circuit.
WALMART MAINTENANCE Electrical Systems 3
What does GFCI stand for in electrical safety?