CEA Tools, Equipment & Testing Procedures 4 — Questions and Answers
Question 1: When bending a 90-degree stub-up in ½" EMT using a hand bender, the electrician must account for the bender's 'take-up' by:
- Adding the take-up distance to the measured mark before bending
- Subtracting the take-up distance from the measured mark before bending (Correct answer)
- Ignoring take-up because it only applies to rigid conduit
- Multiplying the stub height by the take-up percentage
Correct answer: Subtracting the take-up distance from the measured mark before bending
Take-up (gain) is subtracted from the desired stub length because the bend itself adds length to the vertical portion of the conduit.
Question 2: A digital multimeter set to AC volts reads 0V across a switch, but the switch is in the OPEN position. What does this indicate?
- The switch has failed open and has no voltage present
- The load side is at the same potential as the line side—an unexpected condition
- The circuit is properly de-energized and safe to work on
- Voltage is present on both sides of the switch, indicating correct operation (Correct answer)
Correct answer: Voltage is present on both sides of the switch, indicating correct operation
Zero volts across an open switch means both terminals are at the same potential (both hot or both neutral), which is the correct reading for a functioning switch in an energized circuit.
Question 3: Which pulling lubricant is acceptable for use with THHN wire being pulled through PVC conduit?
- Petroleum-based grease
- Wax-based or listed wire-pulling compound (Correct answer)
- Motor oil
- WD-40 spray lubricant
Correct answer: Wax-based or listed wire-pulling compound
Listed wire-pulling compounds (wax or water-based) are compatible with THHN insulation and PVC conduit and do not degrade either material.
Question 4: A voltage drop test on a long branch circuit run is performed by:
- Measuring resistance of the conductors with power off using an ohmmeter
- Measuring voltage at the source and again at the load terminals under load, then comparing (Correct answer)
- Checking current with a clamp meter at the panel only
- Using a megohmmeter to measure insulation resistance under full load
Correct answer: Measuring voltage at the source and again at the load terminals under load, then comparing
Voltage drop is measured by comparing source voltage to load-end voltage while the circuit is carrying its normal load current.
Question 5: When using a come-along (hand ratchet puller) to tension a service entrance conductor, what safety accessory is required on the cable?
- A wire mesh pulling grip (Kellems grip) sized to the cable (Correct answer)
- A standard pipe clamp attached to the insulation
- An alligator clip clamped to the bare conductor
- A tie-wrap bundle around all conductors together
Correct answer: A wire mesh pulling grip (Kellems grip) sized to the cable
A Kellems (wire mesh) grip distributes tension evenly across the cable jacket without damaging insulation or conductor strands.
Question 6: The multiplier used when bending an offset in conduit to determine the length of conduit needed between the two bends is based on:
- The wire fill percentage of the conduit
- The offset depth and the angle of the bends chosen (Correct answer)
- The conduit material (metal vs. PVC)
- The number of conductors being pulled
Correct answer: The offset depth and the angle of the bends chosen
Offset multipliers (e.g., 2.0 for 30°, 1.4 for 45°) are applied to the offset depth to find the distance between bend marks.
Question 7: Which of the following best describes the function of a toning device (tone generator and probe) in electrical work?
- Measures insulation resistance on long cable runs
- Traces and identifies a specific conductor among many without damaging insulation (Correct answer)
- Detects arcing faults inside walls using ultrasonic signals
- Verifies phase sequence in three-phase systems
Correct answer: Traces and identifies a specific conductor among many without damaging insulation
A tone generator applies a signal to one conductor and the inductive probe is used to trace that conductor through bundles or conduit without cutting.
CEA Tools, Equipment & Testing Procedures 4
When bending a 90-degree stub-up in ½" EMT using a hand bender, the electrician must account for the bender's 'take-up' by: