Journeyman Electrician Practice Test 21

Question 1: The resistance of the very large wire is 220 ohms, at 230 volts ac power supply. What is its resistance when a same value of DC power supply is supplied to it?

• 230 ohms
• 210 ohms
• 220 ohms
• 200 ohms

Question 2: The maximum load on a feeder or branch circuit must not exceed ........................ of normal rating of the feeder or branch circuit.

• 80 %
• 75 %
• 90 %
• 85 %

Question 3: No. 12 Type T or TW wire in conduit has an ampacity of 20; if you install it in a 50 ⁰ C ambient, what is its new ampacity?

• 15 amperes
• 20 amperes
• 11.6 amperes
• 14.6 amperes

NEC Reference: NEC 11.6

Question 4: Two smaller wires need not have same cross sectional area to be connected in parallel to form a large wire.

• True
• False

Question 5: For equipment supplied by two ungrounded wires, ....................... switches may be used to disconnect the circuit.

• Single pole switches
• Double pole switches

Question 6: The voltage between conductors on  branch circuits supplying screw-shell lamp-holders, receptacles of dwelling units may not exceed............. volts, except for permanently connected appliances.

• 150
• 100
• 230
• 120

Question 7: The demand factor in calculating ampacity should never applied to branch circuits.

• True
• False

Question 8: The current in electrical circuit takes the least resistance path.

• True
• False

Question 9: An AC system of less than 50 Volts must be grounded which of the following conditions?

• If the supply transformer voltage exceeds 100 volts to ground.
• If the supply transformer is ungrounded
• if it is used as feeder conductor

NEC Reference: NEC 250.20(A)

Question 10: The total current flows through the 3-wire single phase electrical system is .................................

• the sum of the current flowing in two hot conductors
• the difference between the current flowing in two hot conductors