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ASVAB · Electrical Safety

What is the purpose of a fuse or circuit breaker in an electrical system?

Reviewed by Jordan Morley, Editorial Lead at 247SimpleTests. Written by the 247SimpleTests Editorial Team from the official source material cited on every question.

Correct answer

To protect the circuit by interrupting current flow if it exceeds a safe level (preventing overheating and fire)

  1. A To boost voltage
  2. B To protect the circuit by interrupting current flow if it exceeds a safe level (preventing overheating and fire)
  3. C To store electricity
  4. D To increase current

Why this is the answer

A FUSE or CIRCUIT BREAKER protects the circuit by INTERRUPTING current flow if it exceeds a safe level — preventing overheating, damage, and fire. ASVAB Electronics Information tests safety devices. A FUSE contains a thin wire that melts (blowing) when current is too high, breaking the circuit (one-time, must be replaced); a CIRCUIT BREAKER trips and can be reset. Both prevent dangerous overcurrent (from shorts or overloads). They're rated for a specific current (amps). Knowing fuses/breakers protect against overcurrent (preventing fire) is commonly tested.
Source: ASVAB Electronics Information — Fuses and Circuit Breakers

Practice more questions

This question is from our ASVAB Practice Tests practice test. Take the full practice test to test your knowledge across all Electrical Safety and other topics.

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About this topic: Electrical Safety

Electrical safety questions test the practical rules behind the physics: why grounding and fuses exist, what a GFCI does, why current and not voltage is what injures, and how to work on a circuit safely. They are short questions with precise answers. This is one of 3 Electronics Information questions on electrical safety, each with a full explanation on a single study page.

New to this exam? Our ASVAB exam guide explains the format, scoring, and how to prepare.

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