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

Question 11: Per NEC 230.2, a building or structure is normally supplied by:

• Only one service, except for specific listed conditions
• Always exactly three services
• As many services as the owner wants, with no restriction
• No service at all is permitted for any building

NEC Reference: NEC 230.2

Question 12: Per NEC 230.70(A), the service disconnecting means must be installed at a location that is:

• Readily accessible, at or near where service conductors enter the building
• Locked inside a room with no key available
• At least 500 feet from the point of entry
• On the roof only, regardless of building type

NEC Reference: NEC 230.70(A)

Question 13: Per NEC 230.79(B), for an installation consisting of not more than two 2-wire branch circuits, what is the minimum rating of the service disconnecting means?

• 15 amperes
• 30 amperes
• 60 amperes
• 100 amperes

NEC Reference: NEC 230.79(B)

Question 14: Per NEC 230.90, each ungrounded service conductor must have overload protection rated:

• Not more than the allowable ampacity of the conductor
• At least double the conductor ampacity
• There is no overcurrent protection requirement for service conductors
• Exactly equal to the utility transformer rating

NEC Reference: NEC 230.90

Question 15: Per NEC 230.95, ground-fault protection of equipment (GFPE) is required for a solidly grounded wye service (over 150 V to ground, not exceeding 600 V phase-to-phase) when the service disconnect is rated:

• 100 amperes or more
• 400 amperes or more
• 1000 amperes or more
• It is never required regardless of size

NEC Reference: NEC 230.95

Question 16: Per NEC 230.9, overhead service conductors installed as open conductors must be kept how far from windows, doors, porches, and similar openings?

• 1 foot
• 3 feet
• 8 feet
• 10 feet

NEC Reference: NEC 230.9

Question 17: At the service head (weatherhead), service-entrance conductors must form a "drip loop" so that:

• Water drips off the conductors before reaching the service head
• The conductors are shortened to save copper
• The conductors can be spliced without a junction box
• The service head no longer needs to be weatherproof

NEC Reference: NEC 230.54

Question 18: Per NEC 230.66, equipment intended for use as service equipment must be:

• Marked "Suitable for use as service equipment"
• Painted a specific color required by the NEC
• Marked with the installer's name only
• No marking is required at all

NEC Reference: NEC 230.66

Question 19: Per NEC 230.28, a service mast used to support service-drop or overhead service conductors:

• Cannot support other attachments (like an antenna) unless specifically designed for it
• Must always also support a satellite dish
• Can support unlimited additional equipment with no restriction
• Is never permitted to support service-drop conductors

NEC Reference: NEC 230.28

Question 20: Per NEC 230.82, which of the following is normally PERMITTED to be connected on the supply side of the service disconnecting means?

• Meters and meter sockets used for billing purposes
• A general-purpose lighting branch circuit
• A residential kitchen receptacle circuit
• A standard 120 V wall outlet for tools

NEC Reference: NEC 230.82

Question 21: Per NEC 230.6, service conductors can be considered "outside of a building" — and so not yet under service overcurrent protection rules that apply once conductors are inside — when they are, among other conditions:

• Encased in at least 2 inches of concrete, or buried at the required depth
• Painted a bright orange color
• Run through any open attic space
• Left exposed and unprotected inside a finished room

NEC Reference: NEC 230.6

Question 22: The system bonding jumper, which connects the grounded (neutral) conductor to the equipment grounding system, is normally installed:

• Only at the service, not again at a downstream subpanel
• At every subpanel throughout the building
• Only at the farthest branch circuit from the service
• It is not required anywhere in the system

NEC Reference: NEC 250.24

Question 23: A building is normally permitted to have only one electrical service, except under specific conditions listed in the NEC.

• True
• False

NEC Reference: NEC 230.2

Question 24: What size service conductor ampacity is required for a 120/240 volt single-phase service with a calculated demand load of 60 kVA?

• 150 amperes
• 200 amperes
• 250 amperes
• 300 amperes

Question 25: A subpanel located downstream of the main service should have its neutral (grounded) conductor bonded to the equipment grounding system again, the same as at the service.

• True
• False

NEC Reference: NEC 250.24