Course outline
Module 1
Module 1: Electricity Fundamentals
Electricity Fundamentals
Knowledge check
Q1. What is the unit used to measure electrical current?
- A. Volt
- B. Ampere ✓
- C. Ohm
- D. Watt
Why: Electrical current is measured in amperes (amps). Volts measure voltage, ohms measure resistance, and watts measure power.
Q2. Which term describes the electrical 'pressure' that pushes current through a circuit?
- A. Resistance
- B. Capacitance
- C. Voltage ✓
- D. Frequency
Why: Voltage is the potential difference that drives electrons through a circuit, often compared to water pressure in a pipe.
Q3. What does Ohm's Law state about the relationship between voltage, current, and resistance?
- A. Voltage equals current divided by resistance
- B. Voltage equals current multiplied by resistance ✓
- C. Voltage equals resistance minus current
- D. Voltage equals current plus resistance
Why: Ohm's Law states V = I x R, meaning voltage equals current multiplied by resistance. This relationship is fundamental to understanding circuits.
Q4. What is the approximate standard voltage for household outlets in the United States?
- A. 12 volts
- B. 24 volts
- C. 120 volts ✓
- D. 480 volts
Why: Standard U.S. household outlets provide about 120 volts (240 volts for large appliances like dryers and ranges). Europe commonly uses 230 volts.
Q5. What is the primary purpose of a circuit breaker in a home electrical system?
- A. To store electrical energy for later use
- B. To convert AC power into DC power
- C. To interrupt the flow of current when it exceeds a safe level ✓
- D. To measure how much electricity is being used
Why: A circuit breaker automatically shuts off the circuit when current becomes too high, such as during an overload or short circuit, helping prevent overheating and fires.
Module 2
Module 2: Reading Your Electrical Panel
Reading Your Electrical Panel
Knowledge check
Q1. What is the main purpose of a circuit breaker in your electrical panel?
- A. To store electricity for later use
- B. To interrupt the flow of current when it exceeds a safe level
- C. To convert AC power into DC power
- D. To measure how much electricity your home uses
Why: A circuit breaker automatically shuts off power when current exceeds the rated capacity of a circuit, preventing overheating and reducing fire risk.
Q2. What does a breaker rated at 20 amps indicate?
- A. The circuit can safely carry up to 20 amps of current
- B. The circuit operates at 20 volts
- C. The breaker will trip after 20 minutes of use
- D. The circuit serves 20 outlets
Why: The amp rating is the maximum continuous current the circuit wire and devices are designed to handle safely before the breaker trips.
Q3. What is the main service disconnect in a home electrical panel?
- A. A switch that turns off all power to the home
- B. A switch that controls only the lighting circuits
- C. A device that grounds the panel to the earth
- D. A meter that records energy usage
Why: The main disconnect, usually a large breaker at the top of the panel, cuts power to the entire home and is useful for emergencies or maintenance.
Q4. What color wire is typically used for the grounding conductor?
- A. Red
- B. Black
- C. White
- D. Green or bare copper
Why: Green or bare copper wires are reserved for grounding in standard U.S. wiring practice, providing a safe path for fault current.
Q5. If a breaker repeatedly trips when you run a space heater, what is the most likely cause?
- A. The breaker is too large for the wire
- B. The circuit is overloaded because too many devices draw power on it
- C. The panel is not grounded
- D. The main disconnect is turned off
Why: Repeated tripping usually means the circuit is drawing more current than its breaker allows, often from a high-wattage appliance sharing the circuit with others.
Module 3
Module 3: Circuits, Breakers, and Fuses
Circuits, Breakers, and Fuses
Knowledge check
Q1. What is the main purpose of a circuit breaker in a home electrical system?
- A. To store extra electrical energy for later use
- B. To automatically cut off power when current exceeds a safe level ✓
- C. To convert AC power into DC power
- D. To measure how much electricity the home uses
Why: A circuit breaker monitors the current flowing through a circuit and trips (opens) automatically when the current exceeds a safe limit, preventing overheating and reducing fire risk.
Q2. What happens to a fuse after it blows due to an overcurrent?
- A. It resets automatically once the load is removed
- B. It must be replaced with a new fuse of the correct rating ✓
- C. It can be repaired by tightening the terminals
- D. It continues working at a lower capacity
Why: A fuse contains a metal element that melts when overcurrent flows through it. It is a one-time protective device and must be replaced with one of the same amperage rating.
Q3. Why should you never replace a fuse or breaker with one of a higher amp rating than specified?
- A. Higher-rated fuses use more electricity
- B. The wiring may overheat before the protective device trips, creating a fire hazard ✓
- C. Higher-rated fuses are harder to install
- D. It voids the home's electricity meter warranty
Why: The amp rating is matched to the wire gauge. A higher-rated device allows more current than the wire can safely carry, so the wire can overheat and start a fire before the protection activates.
Q4. If a circuit breaker trips repeatedly, what is the most appropriate first step?
- A. Replace the breaker with a higher-rated one
- B. Remove the breaker and leave the circuit unprotected
- C. Unplug or disconnect devices on that circuit to find the overload or fault ✓
- D. Ignore it as long as the lights still work
Why: Repeated tripping signals an overload or a short circuit. Disconnecting devices on the circuit helps identify the cause, which should be fixed rather than masked by a bigger breaker.
Q5. What is the difference between a series circuit and a parallel circuit as commonly used in homes?
- A. Series circuits power outlets, parallel circuits power lights only
- B. In parallel circuits each device gets full voltage and one failure does not stop the others, which is why household wiring is parallel ✓
- C. Series circuits are always safer than parallel circuits
- D. Parallel circuits carry no current
Why: Household circuits are wired in parallel so every appliance receives the full line voltage and operates independently. If one device fails or is switched off, the others keep running.
Module 4
Module 4: Wiring Basics and Safe Materials
Wiring Basics and Safe Materials
Knowledge check
Q1. Which wire color is most commonly used to indicate the ungrounded 'hot' conductor in a standard US household circuit?
- A. Green
- B. Black ✓
- C. White
- D. Bare copper
Why: Black insulation is the conventional color for ungrounded hot conductors that carry current from the panel to outlets and switches. White is used for the neutral conductor, and green or bare copper is used for the equipment grounding conductor.
Q2. What is the main purpose of the grounding conductor in a household electrical circuit?
- A. To carry the normal load current back to the panel
- B. To provide a low-resistance path for fault current so that a breaker trips quickly ✓
- C. To increase the voltage available at outlets
- D. To reduce the amount of current drawn by appliances
Why: The grounding conductor normally carries no current. If a hot wire touches a metal enclosure, the grounding path carries the fault current back to the panel, causing the breaker to trip and removing the shock or fire hazard.
Q3. Which type of wire is generally considered the safest and most appropriate choice for standard fixed wiring in a dry residential interior?
- A. Stranded aluminum wire with no insulation rating
- B. Solid copper wire with THHN or NM-B cable insulation ✓
- C. Bare copper wire run through open air
- D. Steel wire of any gauge
Why: Solid copper conductors with appropriate insulation like THHN or NM-B (Romex) are the standard, reliable choice for dry interior residential wiring. Bare wire, uninsulated conductors, and steel are unsafe for this purpose.
Q4. Why should wire gauge be matched to the circuit breaker amperage?
- A. Thicker wire is always cheaper to install
- B. A wire that is too small for its breaker can overheat before the breaker trips, creating a fire risk ✓
- C. Breakers only work with one specific wire gauge regardless of load
- D. Matching gauge reduces the voltage of the circuit
Why: The breaker protects the wire, not the appliance. If the wire is undersized for the breaker rating, it can overheat under sustained overload before the breaker trips, so wire gauge must be sized to the breaker's amperage.
Q5. Before working on any wiring inside an outlet or switch box, what is the most important first step?
- A. Touch the wires to check for live current
- B. Turn off the correct circuit breaker and verify the circuit is de-energized with a voltage tester ✓
- C. Remove the outlet cover while the power is still on
- D. Connect a jumper wire across the terminals
Why: Switching off the correct breaker and confirming with a non-contact or two-pole voltage tester that no voltage is present protects you from electric shock. Relying on a switch position or touching wires is unsafe.
Module 5
Module 5: Outlets, Switches, and Light Fixtures
Outlets, Switches, and Light Fixtures
Knowledge check
Q1. Before replacing a wall switch or light fixture, what is the most important first step?
- A. Test the wire with your bare fingers to confirm it is live
- B. Turn off the circuit breaker that powers the device and verify the power is off with a non-contact voltage tester
- C. Remove the cover plate while the switch is still on
- D. Unscrew the device and check the wires with a metal screwdriver
Q2. What does the green screw or green wire on a standard outlet or fixture connect to?
- A. The hot (live) wire
- B. The neutral wire
- C. The grounding (earth) conductor
- D. The switched leg of the circuit
Q3. In a standard single-pole light switch, which wire is typically connected to the brass or 'line' terminal?
- A. The neutral wire
- B. The ground wire
- C. The incoming hot wire from the power source
- D. The wire going to the light fixture
Q4. Why should outlets in bathrooms, kitchens, garages, and outdoor areas typically be GFCI-protected?
- A. They provide higher voltage for appliances
- B. They detect current leakage and cut power quickly to reduce the risk of electric shock
- C. They prevent circuit overloads by limiting the number of devices
- D. They reduce electricity bills by monitoring usage
Q5. When installing a ceiling light fixture, what is the recommended practice for the fixture's weight?
- A. Rely on the electrical box's cable clamp to hold the fixture
- B. Use only the thin screws that came with the fixture
- C. Use a fixture-rated electrical box that is securely anchored to a ceiling joist or brace
- D. Attach the fixture to the drywall using plastic anchors
Module 6
Module 6: Electrical Safety and Shock Prevention
Electrical Safety and Shock Prevention
Knowledge check
Q1. What is the most important first step before working on an electrical outlet or switch in your home?
- A. Touch the wires with the back of your hand to check for voltage
- B. Turn off the circuit breaker that controls the device and verify the power is off with a voltage tester
- C. Wear rubber-soled shoes and work quickly
- D. Unscrew the cover plate and check the wires visually
Q2. What is the approximate amount of current that can be fatal to a person?
- A. About 1 milliamp
- B. About 10 milliamps
- C. About 100 milliamps
- D. About 1 amp
Q3. What type of outlet is designed to shut off power quickly when it detects a ground fault, commonly required in kitchens and bathrooms?
- A. Tamper-resistant outlet
- B. USB outlet
- C. Ground Fault Circuit Interrupter (GFCI) outlet
- D. Surge-protected outlet
Q4. Why should you never use an extension cord as a permanent wiring solution?
- A. Extension cords always carry more voltage than household wiring
- B. Extension cords are designed for temporary use and can overheat, creating fire and shock hazards if used long-term
- C. Extension cords cannot be plugged into grounded outlets
- D. Extension cords drain electricity from other circuits in the house
Q5. If you receive a mild electric shock from an appliance, what should you do first?
- A. Keep using the appliance to see if the problem repeats
- B. Immediately unplug the appliance or turn off its power source, and stop using it until it has been inspected or repaired
- C. Touch a metal pipe to ground the shock
- D. Cover the appliance with a towel and continue using it
Module 7
Module 7: When to Call a Licensed Electrician
When to Call a Licensed Electrician
Knowledge check
Q1. Which of the following situations is the best reason to call a licensed electrician rather than handling the work yourself?
- A. Replacing a burned-out light bulb in a ceiling fixture
- B. Discovering a burning smell coming from an outlet ✓
- C. Changing the batteries in a smoke detector
- D. Tightening a loose cover plate on a light switch
Why: A burning smell from an outlet can indicate overheating, arcing, or a failing connection, which poses a fire risk. This calls for a licensed electrician to diagnose and repair the problem safely.
Q2. A homeowner notices that a circuit breaker trips repeatedly whenever a space heater is plugged in. What is the most appropriate next step?
- A. Replace the breaker with a higher amperage one so it stops tripping
- B. Keep resetting the breaker until the heater warms up the room
- C. Stop using the space heater and have a licensed electrician check the circuit ✓
- D. Wrap the breaker in tape to prevent it from tripping
Why: Repeated tripping signals an overloaded or faulty circuit. Installing a larger breaker can cause wires to overheat and start a fire, so a licensed electrician should evaluate the circuit's capacity and wiring.
Q3. Which of these is a sign that a home's electrical wiring may need professional inspection?
- A. The light switches are a different color than the outlets
- B. Lights dim noticeably when a large appliance like an air conditioner starts up ✓
- C. The wall plates have a few small scratches on them
- D. The homeowner has replaced a few outlet covers
Why: Lights that dim when large appliances start can indicate undersized wiring, a poor connection, or an overloaded circuit. These issues should be assessed by a licensed electrician.
Q4. Before doing any electrical work at home, what should a homeowner always do first?
- A. Check the weather forecast to avoid storms
- B. Turn off the power at the breaker panel for the affected circuit ✓
- C. Unplug the refrigerator to protect it
- D. Open all the windows to ventilate the room
Why: Shutting off power at the breaker panel de-energizes the circuit and greatly reduces the risk of electric shock. Verifying the circuit is dead with a tester is also a key safety step.
Q5. Which task is generally considered appropriate for a homeowner without an electrician's license to attempt?
- A. Adding a new 240-volt circuit for an electric dryer
- B. Upgrading the main electrical panel
- C. Replacing a standard wall switch with an identical one, with the power off ✓
- D. Running new wiring through the walls to add outlets
Why: Replacing a like-for-like switch with the power off is a simple, low-risk task many homeowners can do safely. Panel work, new circuits, and new wiring typically require a licensed electrician and often a permit.