Chapter 16 Quiz: Electrical Safety and Common Problems
Multiple Choice
1. What electrical condition does a GFCI protect against that a standard circuit breaker does NOT?
a) Overloaded circuits drawing too much current b) Ground faults — current finding a path to ground through a person or unintended conductor c) Arc faults caused by damaged or loose wiring d) Power surges from lightning or utility fluctuations
Correct answer: b Circuit breakers protect against overloads (too much current). GFCIs protect against ground faults — current leaking to ground at as little as 4–6 milliamps, far below what a breaker detects. This is the amount of current that can cause fatal electrocution.
2. You press the TEST button on a GFCI outlet and the outlet stays live (nothing shuts off). This means:
a) The GFCI is working correctly — TEST is just a reset function b) The GFCI outlet is wired correctly and protecting downstream outlets c) The GFCI has a failed trip mechanism and must be replaced d) The GFCI is in "always on" mode designed for medical equipment
Correct answer: c A GFCI that doesn't cut power when TEST is pressed has a failed trip mechanism. It may still provide power, but it provides NO protection against ground faults. Replace it immediately.
3. An Arc Fault Circuit Interrupter (AFCI) is designed primarily to prevent:
a) Electrocution from ground faults in wet locations b) Electrical fires caused by arcing at damaged or loose connections c) Overloaded circuits from drawing too much current d) Voltage spikes during thunderstorms
Correct answer: b AFCI breakers detect the distinctive electrical signature of arcing — electricity jumping between conductors through damaged insulation, loose connections, or pinched wires. Arcing can cause fires at current levels that never trip a standard breaker.
4. The Federal Pacific Electric Stab-Lok panel is considered dangerous primarily because:
a) It uses aluminum bus bars that corrode rapidly b) Its circuit breakers frequently fail to trip when the circuit is overloaded c) It lacks ground fault protection on all circuits d) Its breakers can be installed in the wrong slot, reversing polarity
Correct answer: b Testing by independent engineers found that Stab-Lok breakers fail to trip under overload conditions in 25–65% of cases. A breaker that won't trip allows overloaded wiring to continue heating — the primary mechanism for electrical fires.
5. Which of the following is the most reliable visual identifier of a Federal Pacific Stab-Lok panel?
a) A rust-stained gray metal door b) Blue and green colored breaker handles c) Red-striped breaker handles d) A round dial instead of individual breakers
Correct answer: c The red stripe on the breaker handles is the most distinctive and reliable visual identifier of FPE Stab-Lok panels. This visual feature is nearly unique to this panel type and immediately identifiable even without reading any labels.
6. Aluminum branch circuit wiring (installed in many homes 1965–1973) is considered hazardous primarily because:
a) Aluminum conducts electricity poorly compared to copper b) Aluminum is flammable when exposed to air c) Connections made with aluminum wiring loosen and oxidize over time, creating resistance and heat that can lead to fires d) Aluminum wiring is incompatible with modern GFCI outlets
Correct answer: c Aluminum itself conducts adequately. The hazard is at connections: aluminum expands/contracts more than copper, its surface oxidizes (and aluminum oxide is a poor conductor), and it reacts galvanically with copper. The result is loose, hot connections — fire precursors.
7. A circuit breaker that trips immediately when reset (rather than staying on) indicates:
a) The breaker is old and should be replaced with a higher-rated model b) A fault on the circuit — either a short circuit or ground fault — that must be investigated c) The circuit is working correctly; this is normal behavior for a loaded circuit d) The breaker is incompatible with LED lighting on the circuit
Correct answer: b Immediate re-tripping means the circuit has a fault condition — not just an overload. Continuing to reset the breaker can cause a fire. Turn off the breaker and call an electrician.
8. You notice that the outlet cover plate in your laundry room is warm to the touch, even with nothing currently plugged in. You should:
a) Replace the outlet with a GFCI model as soon as possible b) Ignore it — outlet covers often get warm near appliances c) Turn off that circuit breaker and call an electrician d) Check whether the circuit is on a 15A or 20A breaker and upgrade if needed
Correct answer: c A warm outlet cover with nothing plugged in indicates current flowing through a resistance that should be near zero — a sign of a failing connection or wiring fault. This is a fire precursor requiring immediate attention, not a "monitor and wait" situation.
9. What is the correct maximum continuous load for a 20-amp circuit?
a) 20 amps (2,400 watts) b) 18 amps (2,160 watts) c) 16 amps (1,920 watts) d) 15 amps (1,800 watts)
Correct answer: c The NEC specifies that continuous loads (lasting 3+ hours) should not exceed 80% of circuit capacity. For a 20-amp circuit: 20 × 0.80 = 16 amps, or 1,920 watts. This prevents wiring from running at its absolute maximum indefinitely.
10. What is the FIRST action required when you smell burning electrical odor (acrid, plastic/rubber burning smell) in your home?
a) Locate the source and turn off the circuit breaker for that area b) Get everyone out of the house and call 911 or the fire department c) Turn off the main breaker and then investigate d) Call an electrician for a same-day emergency visit
Correct answer: b Burning electrical smell is an evacuation trigger — not an "investigate first" situation. Electrical fires can smolder in walls for extended periods before breaking through. Get out, then call 911. Do not re-enter until fire department personnel confirm it's safe.
Short Answer
Short Answer 1: Explain why a homeowner should never solve a repeatedly tripping 15-amp breaker by replacing it with a 20-amp breaker.
Model answer: The circuit breaker's amperage rating corresponds to the safe continuous current capacity of the wiring on that circuit. A 15-amp breaker protects 14-gauge wiring designed to carry 15 amps safely. Replacing it with a 20-amp breaker doesn't increase the wiring's capacity — it just removes the protection that prevents the wiring from overheating. The wiring can now draw 20 amps through conductors rated for 15, generating heat inside the walls. The correct solution is to reduce the load on the circuit, or to run a new properly sized circuit if more capacity is genuinely needed.
Short Answer 2: Miguel Rodriguez discovers a Federal Pacific Stab-Lok panel in his basement. Describe the appropriate immediate response and the longer-term action plan.
Model answer: The appropriate immediate response is not to panic or evacuate, but to schedule a licensed electrician promptly — within weeks. The FPE Stab-Lok panel is a serious long-term hazard (documented breaker failure rate) but not typically an immediate evacuation emergency. The longer-term action plan: get three quotes for full panel replacement (including considering a service upgrade from 100 to 200 amps if the home's service is undersized), confirm the work requires a permit and inspection, notify the homeowner's insurance company of the existing hazard and planned replacement, and schedule the work. Miguel and Isabel should not continue indefinitely deferring this replacement — the documented failure modes make it a genuine fire risk that compounds over time.
Short Answer 3: Describe the decision framework for whether an electrical problem requires calling 911, calling an electrician same day, or scheduling an electrician within the week.
Model answer: Call 911 immediately for: burning smell, visible smoke, sustained sparking or arcing, or visible fire — these are evacuation triggers. Call an electrician same day for: a breaker that trips immediately upon reset (fault condition), an outlet or switch cover that's hot to the touch, shocks received from outlets, or crackling sounds from the panel. Schedule an electrician within a week for: identified FPE/Zinsco panel, confirmed aluminum wiring, frequently tripping breakers that do reset, GFCIs that fail testing, or a panel with no circuit directory and unknown configuration. Handle yourself: single outlet that's dead (check GFCI upstream and breaker), lights flickering on one circuit (check dimmer, bulb seating, connections), or a breaker that tripped once and resets cleanly.