Service conductor practice test questions-1

Question 1: what is the smallest copper wire size that can be used for service entrance conductors?

• 8 AWG
• 6 AWG
• 10 AWG
• 12 AWG

NEC Reference: NEC 230.31(B)

Question 2: In a three phase balanced 4-wire system, the current in the neutral conductor .....................

• is same as un-grounded conductor
• is lower than other conductors
• is higher than other conductos
• will not flow as the circuit is balanced

Question 3: What is the minimum size electrical service required for a single family dwelling unit?

• 100 amperes
• 150 amperes
• 200 amperes
• 50 amperes

NEC Reference: NEC 230.79(C)

Question 4: For each service , what are the maximum allowable service dis-connectors?

• 4
• 2
• 6
• 8

NEC Reference: NEC 230.71(A)

Question 5: What is the minimum vertical clearance that should be provided for service conductors from the height point of over which they pass?

• 6 feet
• 8 feet
• 10 feet
• 12 feet

NEC Reference: NEC 230.24(A)

Question 6: The 400 volts over head conductors that passes over public street must have a clearance of ..........

• 15 feet
• 10 feet
• 24 feet
• 18 feet

NEC Reference: NEC 230.24(B)(4)

Question 7: When multi conductor cables are used as overhead service conductors, they must be attached to building or other structures by ............................

• Tie wires
• Safe enclosures
• fittings approved for the purpose
• proper long nails

NEC Reference: NEC 230.27

Question 8: Service entrance cables shall be supported by strops with in ................. distance of every service head.

• 24 inches
• 36 inches
• 12 inches
• 15 inches

NEC Reference: NEC 230.51(A)

Question 9: The metal enclosures used for service conductor and equipment ..................

• must never be grounded
• must be grounded
• should be coated with non conducting material
• should have clearance of 30 inches b/w enclosure and equipment

NEC Reference: NEC 250.80

Question 10: What size service conductor is required for a 120/240 volts single phase with a demand load of 48 KVA?

• 200 amperes
• 150 amperes
• 100 amperes
• 250 amperes