⚡ Electrician's Helper Exam Study Guide

Overview

An Electrician's Helper works alongside licensed electricians in city facilities: carrying and preparing materials, pulling wire, installing conduit and fixtures, and keeping the work area safe and organized. It is a hands-on support role, but it requires real electrical knowledge — you must understand what you are handling and why safety procedures are never optional.

The exam tests basic electrical theory, safe work practice, tools and materials, simple calculations, and the ability to read diagrams and follow instructions. It is a multiple-choice exam, and for DCAS multiple-choice exams the pass mark is generally 70%. You are not expected to design circuits — you are expected to understand them, work safely around them, and do the arithmetic correctly.

Use this guide to build your theory from the ground up: Ohm's law first, then series and parallel circuits, then safety and tools. Work the calculation questions with pencil and paper until the formulas are automatic.

What the exam typically tests

Topic checklist

Work through this list honestly — drill the items you cannot do yet.

• ☐ State Ohm's law (V = IR) and rearrange it to solve for any one of voltage, current, or resistance.
• ☐ Calculate power with P = VI and P = I²R.
• ☐ Find total resistance for resistors in series and for two equal resistors in parallel.
• ☐ Explain the difference between a series and a parallel circuit and what happens when one bulb fails in each.
• ☐ Explain what grounding does and why a three-prong plug matters.
• ☐ Describe lockout/tagout and the steps to make a circuit safe before work begins.
• ☐ Name the PPE for electrical work and when each item is used.
• ☐ Identify the correct tool for stripping wire, testing voltage, pulling wire through conduit, and bending conduit.
• ☐ Read a simple schematic and identify the switch, load, and power source, and trace the current path.
• ☐ Explain what a circuit breaker and a fuse do, and why you never replace a fuse with one of a higher rating.
• ☐ Describe the first actions in an electrical emergency, including not touching a victim who is still in contact with a live source.
• ☐ Explain the difference between AC and DC current and where each is commonly found.

How to prepare

Common mistakes to avoid

• ✕ Mixing up the Ohm's law rearrangements — for example, dividing when you should multiply. Write the formula down first, then substitute the numbers.
• ✕ Adding resistances in parallel the way you add them in series. In parallel, total resistance drops below the smallest branch — if your answer is bigger than the smallest resistor, it is wrong.
• ✕ Forgetting units and decimal places in power calculations. A 2,000-watt load at 240 volts draws about 8.3 amps, not 83 — check that your answer is a sensible size.
• ✕ Choosing a repair step before the safety step. In scenario questions, de-energize, test, and lock out come before touching anything.
• ✕ Replacing a blown fuse with a higher-rated one, or bypassing a breaker. The correct answer is always to find and fix the cause, then replace like for like.
• ✕ Guessing at a schematic symbol instead of learning them. Symbols are free marks once you know them, and they appear in several questions.

Exam day strategy

• ✓ Arrive early with the identification and materials your exam notice asks for, and leave yourself extra travel time.
• ✓ For calculation questions, write the formula first, then the numbers, then solve — and sanity-check the size of your answer before moving on.
• ✓ Read the whole scenario before choosing. Safety questions often hide the key hazard in the last sentence.
• ✓ When a question asks for the best first step on a live or possibly live circuit, the safe answer — de-energize and test — is almost always correct.
• ✓ Do not leave questions blank. Eliminate the clearly wrong choices, make your best choice, and move on — you can return to flagged questions if time allows.
• ✓ If a diagram question confuses you, trace the circuit with your finger from the power source through each component. The path usually makes the answer clear.

Sample questions

Try these 3 sample questions from the practice bank. The correct answer is marked — read the explanation even when you get one right.

Official sources

The exam announcement (Notice of Examination) is the final authority for the exam you are taking. Always check it for the exact subjects tested, eligibility requirements, and exam procedures, since details can differ between titles and exam administrations.