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Free CEST Practice Questions

10 free, exam-style Certified Electrical Safety Technician (CEST) practice questions with answers and explanations. No signup required. Work through them below, then take the full free CEST practice test to study every exam domain.

Question 1

A technician opens the disconnect, applies a lock and tag, and releases all stored energy. Before the circuit can be considered to be in an electrically safe work condition, the technician must still:

  1. Reopen the disconnecting device and confirm it a second time
  2. Apply a second backup lockout device to the same disconnect
  3. Test for the absence of voltage with a verified instrument
  4. Record the completed lockout in the facility maintenance log
Show answer & explanation

Correct answer: C - Test for the absence of voltage with a verified instrument

Question 2

Immediately before and after testing for the absence of voltage, a qualified person confirms the test instrument is working by:

  1. Reviewing the date on the calibration sticker
  2. Inspecting the leads and probes for visible cracks
  3. Operating it on a known energized voltage source
  4. Comparing the reading to the equipment nameplate
Show answer & explanation

Correct answer: C - Operating it on a known energized voltage source

Question 3

Work involves several energy sources and two crews across two shifts. This situation calls for complex lockout/tagout, which (unlike simple lockout/tagout) specifically requires:

  1. A separately rated, higher-strength padlock issued to each worker
  2. An energized electrical work permit
  3. Removal of all locks at the end of each shift
  4. A written plan of execution and a person in charge
Show answer & explanation

Correct answer: D - A written plan of execution and a person in charge

Question 4

When selecting a voltage test instrument to verify an electrically safe work condition, the MOST important consideration is that the instrument is:

  1. Rated for the voltage and category of the circuit
  2. The lowest-cost meter currently available in the shop
  3. One the technician has used many times on similar jobs
  4. Equipped with a large, easy-to-read digital display
Show answer & explanation

Correct answer: A - Rated for the voltage and category of the circuit

Question 5

A qualified person must work near an exposed, fixed circuit part on a 480-volt panelboard. Using Table 130.4(E)(a), what is the limited approach boundary?

  1. 1 ft 0 in
  2. 3 ft 6 in
  3. 5 ft 0 in
  4. 10 ft 0 in
Show answer & explanation

Correct answer: B - 3 ft 6 in

Question 6

The arc flash boundary is defined as the distance from a prospective arc source at which the incident energy equals:

  1. 1.2 cal/cm²
  2. 8.0 cal/cm²
  3. 40 cal/cm²
  4. 1.2 J/cm² (joules)
Show answer & explanation

Correct answer: A - 1.2 cal/cm²

Question 7

All other factors held constant, which change would REDUCE the incident energy a worker is exposed to during an arc flash event?

  1. Lengthening the fault clearing time
  2. Raising the available short-circuit current
  3. Increasing the worker's working distance
  4. Shortening the worker's working distance
Show answer & explanation

Correct answer: C - Increasing the worker's working distance

Question 8

Within the hierarchy of risk control methods, which control is considered the LEAST effective and is intended as the last line of defense?

  1. Elimination
  2. Engineering controls
  3. Administrative controls such as procedures and training
  4. Personal protective equipment
Show answer & explanation

Correct answer: D - Personal protective equipment

Question 9

An unqualified person is permitted to cross the limited approach boundary only when they are:

  1. Wearing arc-rated clothing for the task
  2. Continuously escorted by a qualified person
  3. Working on a system operating below 600 volts
  4. Holders of an employer's online safety awareness certificate
Show answer & explanation

Correct answer: B - Continuously escorted by a qualified person

Question 10

A facility wants to perform a task energized because de-energizing would shut down a hospital's life-support equipment. Under NFPA 70E, this justification is:

  1. Unacceptable, because energized work is never permitted under any condition
  2. Unacceptable, because only added cost can justify it
  3. Acceptable, because de-energizing introduces a greater hazard
  4. Acceptable, but only if the task takes under 15 minutes
Show answer & explanation

Correct answer: C - Acceptable, because de-energizing introduces a greater hazard

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