Free NCCER Power Line Worker: Distribution Knowledge Assessment Practice Questions

Sample Practice Questions

Try these 10 sample questions from the NCCER Power Line Worker: Distribution Knowledge Assessment practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1A distribution crew is about to work beside an exposed line that has not gone through the required deenergizing procedure. How should the crew treat that line?

   1. A. As deenergized after an open switch is visible
   2. B. As energized until the required deenergizing procedure is complete
   3. C. As deenergized after a protective cover is installed
   4. D. As energized only after voltage is measured

   Answer: B

   Explanation: OSHA states, "Electric lines and equipment shall be considered and treated as energized unless they have been deenergized in accordance with paragraph (d) or (m) of this section." The visible switch or cover does not establish deenergized status under the cited procedure.

   Reference: Electric power generation, transmission, and distribution, 29 CFR 1910.269 — 29 CFR 1910.269(l)(1)(iii)

2. 2A line worker compares two DC control-circuit conductors made of the same material and cross-sectional area. One conductor is twice as long. How does its resistance compare?

   1. A. It is one-half the shorter conductor's resistance.
   2. B. It is the same as the shorter conductor's resistance.
   3. C. It is twice the shorter conductor's resistance.
   4. D. It is four times the shorter conductor's resistance.

   Answer: C

   Explanation: DOE states, "The resistance of a given length of conductor depends upon the resistivity of that material, the length of the conductor, and the cross-sectional area of the conductor, according to Equation (2-1)." Its R=ρL/A relation gives twice the resistance when length doubles with the other properties fixed.

   Reference: DOE Fundamentals Handbook: Electrical Science, Volume 1 — Module 2, DC Circuit Terminology, Resistivity, p. 16

3. 3A line worker prepares the OSHA hammer test on a wood pole before climbing. Approximately what hammer weight does the guidance specify?

   1. A. 1 pound (0.45 kg).
   2. B. 3 pounds (1.4 kg).
   3. C. 5 pounds (2.3 kg).
   4. D. 8 pounds (3.6 kg).

   Answer: B

   Explanation: OSHA says, "Rap the pole sharply with a hammer weighing about 1.4 kg (3 pounds)". The approximate specified weight is 3 pounds, rather than another size of inspection hammer.

   Reference: Methods of Inspecting and Testing Wood Poles, 29 CFR 1910.269 Appendix D — Appendix D, III.A, Hammer test

4. 4A crew is framing a pole on a curved 12.47/7.2 kV RUS distribution line. On which side of the pole should the crossarm face?

   1. A. The side facing the midpoint of the curve
   2. B. The side facing the outside of the curve
   3. C. The side facing the incoming span alone
   4. D. The side facing the outgoing span alone

   Answer: A

   Explanation: RUS Bulletin 1728F-804 says, "On lines that curve, the crossarms shall be installed on the side of the pole that faces the midpoint of the curve." The midpoint side controls the framing orientation in this curved-line case.

   Reference: USDA RUS Bulletin 1728F-804: Specifications and Drawings for 12.47/7.2 kV Line Construction — Section W, Construction Specifications for Poles and Crossarms

5. 5At the start of a shift constructing an overhead distribution line, the crew will use a rotating pole-setting machine. When must its critical safety components receive a thorough visual inspection?

   1. A. Before use on each shift
   2. B. Before use once each day
   3. C. Before use once each week
   4. D. Before use after each repair

   Answer: A

   Explanation: OSHA states, "The critical safety components of mechanical elevating and rotating equipment shall receive a thorough visual inspection before use on each shift." This covers the rotating equipment used in the construction shift.

   Reference: Mechanical Equipment, 29 CFR 1926.959 — 29 CFR 1926.959(a)(2)

6. 6A line worker uses a suitable voltmeter to check the voltage across a distribution control-circuit load while the circuit is operating. How is the meter connected relative to the load?

   1. A. In parallel with the load
   2. B. In series with the load
   3. C. Across an open ground path
   4. D. Across a shorted supply path

   Answer: A

   Explanation: The DOE handbook states, "Voltmeters are connected in parallel with the load (RL) being measured." The meter probes belong across this load.

   Reference: DOE Fundamentals Handbook: Electrical Science, Volume 4 — ES-14, Voltmeters, p. 5

7. 7A pole-mounted device on a distribution feeder trips for a fault and is designed to close automatically according to its control sequence. Which device is it?

   1. A. Automatic circuit recloser
   2. B. Automatic sectionalizer
   3. C. Distribution fuse
   4. D. Step voltage regulator

   Answer: A

   Explanation: The RUS guide says recloser controls permit "instantaneous and time-delayed trips and automatic reclosures" and notes that these devices can be mounted on poles along the feeder. That automatic reclosure identifies the device.

   Reference: USDA RUS Bulletin 1724E-300: Design Guide for Rural Substations — Section 12.4.3.2, Automatic Circuit Reclosers, p. 625

8. 8A crew is supporting a conductor at intermediate structures while sagging several unequal distribution spans. Which device allows the conductor to move freely between the spans?

   1. A. Free-wheeling stringing sheave.
   2. B. Dead-end conductor clamp.
   3. C. Anchored conductor grip.
   4. D. Fixed suspension tie.

   Answer: A

   Explanation: RUS states that intermediate structures support conductors with "free-wheeling rollers (stringing sheaves or blocks) that permit the conductor to move freely between spans." The sheave provides the needed movement.

   Reference: USDA RUS Bulletin 1724E-152: Mechanics of Overhead Distribution Line Conductors — Section 2.4(b), Application of Equations to Actual Design Conditions, p. 8

9. 9A crew is evaluating a southern yellow pine distribution pole for decay that may begin below ground. Which inspection approach exposes the section most susceptible to this decay?

   1. A. Excavate around the pole and inspect the exposed groundline surface.
   2. B. Sound the aboveground pole and inspect the struck surface.
   3. C. Bore the aboveground pole and inspect the extracted shavings.
   4. D. Visually inspect the pole and its aboveground hardware.

   Answer: A

   Explanation: RUS states, "Excavation exposes the most susceptible section of the pole for inspection. For southern yellow pine this is particularly true, since decay begins externally and below ground." Excavation lets the worker inspect the at-risk surface.

   Reference: USDA RUS Bulletin 1730B-121: Wood Pole Inspection and Maintenance — Section 4, Excavation, p. 9

10. 10During live-line barehand work, an aerial lift shows an indication of equipment malfunction. What action does OSHA require immediately?

    1. A. Suspend work from that aerial lift.
    2. B. Repeat the scheduled boom-current test.
    3. C. Transfer to a lower-voltage circuit.
    4. D. Reposition the bucket away from the line.

    Answer: A

    Explanation: OSHA states, "The employer shall immediately suspend work from the aerial lift when there is any indication of a malfunction in the equipment." A test, circuit change, or repositioning does not replace immediate suspension.

    Reference: OSHA 29 CFR 1910.269, Electric Power Generation, Transmission, and Distribution, continued — 29 CFR 1910.269(q)(3)(xiii)(C)