BC Electrician Level 1 Practice Exam
Free · 90 Questions.

• 3 A
• 0.67 A
• 1 A
• 2 A

Why: Each branch sees the full 120 V. Branch currents are 120 ÷ 60 = 2 A and 120 ÷ 120 = 1 A. Total current is the sum of the branch currents: 3 A.

• It still circles the wire but in the opposite direction
• It stays in the same direction, since it depends on current size
• It lines up parallel to the wire in the new direction of flow
• It collapses to zero until the original polarity is restored

Why: Under the left-hand rule (thumb along electron flow, fingers curling in the direction of the flux lines), the field circles the conductor and its direction follows the direction of electron flow. Reversing the flow reverses the circulation of the field, which stays perpendicular to the current.

• Wear close-fitting clothing and remove rings, bracelets and watches
• Wear loose cotton sleeves and keep a metal wristwatch on to track time
• Wear close-fitting clothing but keep rings on if gloves cover them
• Wear loose clothing and tuck dangling neckwear into a shirt pocket

Why: Section 8.10(2) says that where there is danger of contact with electrically energized equipment, clothing must fit closely about the body, dangling neckwear, bracelets, wristwatches, rings or similar articles must not be worn (a medical alert bracelet on a snug transparent band is an exception), and hair must be confined.

• The meter supplies its own test voltage, and outside voltage invalidates the reading
• The meter supplies no test voltage, so it cannot read while the circuit is energized
• The meter can only read resistance when current is flowing at the line voltage
• The meter reading would still be correct, but the display could not be read

Why: An ohmmeter has its own internal battery to send a small current through the circuit under test. If the circuit has its own voltage source, the extra voltage invalidates the reading and may damage the meter. Always isolate and verify first.

• Its average current is too low to trip the breaker but can still start a fire
• The arc raises the voltage so high that the breaker contacts weld themselves shut
• Arcs occur on DC circuits, which standard breakers do not monitor or respond to
• The arc draws its current on the ground wire, which the breaker does not see in use

Why: A standard breaker opens quickly on a heavy overload and more slowly on a small overload, but an arc is a highly variable load whose average current is not enough to trip it, even though it can ignite nearby material. An arc fault circuit interrupter (AFCI) contains electronics that sense the intermittent resistive short circuit and open the circuit.