semplr.

Exams · Certifications · Licensing

Journeyman Electrician Exam (NEC-based)

Electrical theory: practice questions

Our Journeyman Electrician bank has 41 questions on this topic. Here are 5 of them with answers; the full mock exam draws from every topic, like the real one.

Start the free mock exam

Question 1

What is 'ampacity'?

  1. The voltage rating
  2. The breaker size
  3. The insulation thickness
  4. The maximum current a conductor can carry continuously under the conditions of use without exceeding its temperature rating
Show the answer

D. The maximum current a conductor can carry continuously under the conditions of use without exceeding its temperature rating — Ampacity depends on conductor size, material, insulation and conditions.

Question 2

What is an open circuit?

  1. A break in the circuit so no current flows
  2. A grounded circuit
  3. A short circuit
  4. A circuit carrying too much current for its conductors
Show the answer

A. A break in the circuit so no current flows — A burned-out fuse creates an open.

Question 3

What is the purpose of a ground rod clamp listed for direct burial?

  1. To make a durable connection between the grounding electrode conductor and the rod
  2. To hold the rod in place
  3. To insulate the rod
  4. To measure resistance
Show the answer

A. To make a durable connection between the grounding electrode conductor and the rod — Clamps must be listed for the purpose.

Question 4

In a 208Y/120-volt three-phase system, what is the voltage between any phase and neutral?

  1. 208 volts
  2. 277 volts
  3. 120 volts
  4. 240 volts
Show the answer

C. 120 volts — Phase-to-phase is 208 V.

Question 5

What happens to current if voltage stays the same and resistance doubles?

  1. Current halves
  2. Current becomes zero
  3. Current stays the same
  4. Current doubles
Show the answer

A. Current halves — Ohm's law: I = E ÷ R.

More Journeyman Electrician topics