N.E.C. Chapter 2

What is the minimum size service entrance conductor needed to feed a water heater rated at 120V, 5A?

A. #16 AWG Cu B. #14 AWG Cu > 230.79(A) & 230.42(B) C. #12 AWG Cu D. #10 AWG Cu

What is the minimum vertical clearance needed for 240V overhead service conductors above a residential driveway?

A. 10ft B. 12ft > 230.24(B)(2) C. 15ft D. 18ft

What is the minimum size equipment grounding conductor needed for equipment fed from a 40A breaker?

A. 12 AWG B. 10 AWG > 250.102(D) & Table 250.122 C. 8 AWG D. 6 AWG

If a set of 120/240V overhead feeder conductors terminates at a through-the-roof raceway or approved support, with not more than 6 ft of these conductors, 4 ft horizontally, passing over the roof overhang, the minimum clearance above the roof for these conductors is not less than ______.

A. 12in B. 18in > 225.19(A)Ex3 C. 2ft D. 5ft

If multiple rod, pipe or plate electrodes are installed, they shall not be less than ______ ft apart.

A. 4 B. 6 > 250.53(A)(3) C. 8 D. 12

A demand factor of ______ percent applies to a multifamily dwelling with ten units if the optional calculation method is used.

A. 43 > Table 220.84 B. 50 C. 60 D. 75

Where fixed multi-outlet assemblies are used in other than dwelling units or the guest rooms of hotels or motels, each ______ ft or fraction thereof of each separate and continuous length shall be considered as one outlet of not less than 180 VA where appliances are unlikely to be used simultaneously.

A. 5 > 220.14(H)(1) B. 5 1⁄2 C. 6 D. 6 1/2

The total rating of utilization equipment fastened in place shall not exceed ______ % of the branch circuit ampere rating where lighting units and cord and plug connected utilization equipment are supplied.

A. 50 > 210.23(A)(2) B. 75 C. 100 D. 125

Receptacle outlets in or on floors shall not be counted as part of the required number of receptacle outlets for dwelling unit wall spaces, unless they are located within ______ in. of the wall.

A. 6 B. 12 C. 18 > 210.52(A)(3) D. 24

An insulated grounded conductor ______ AWG or smaller shall be identified by a continuous white or gray outer finish, or by three continuous white or gray stripes along its entire length on other than green insulation.

A. 8 B. 6 > 200.6(A)(1-3) C. 4 D. 3

If the circuit's overcurrent device exceeds ______, the conductor ampacity must have a rating not less than the rating of the overcurrent device.

A. 800A > 240.4(C) B. 1000A C. 1200A D. 2000A

For other than dwelling occupancies, banks, or office buildings, each receptacle outlet shall be calculated at not less than ______ VA.

A. 90 B. 180 > 220.14(I) C. 270 D. 360

To determine the feeder calculated load for ten 3 kW household cooking appliances, use ______ of Table 220.55.

A. Column A > 220.55 B. Column B C. Column C D. none of these

Grounded electrical systems shall be connected to earth in a manner that will ______.

A. limit voltages due to lightning, line surges, or unintentional contact with higher-voltage lines B. stabilize the voltage-to-ground during normal operation C. facilitate overcurrent device operation in case of ground faults D. both A and B > 250.4(A)(1)

On a three-phase, 4-wire, delta-connected service where the midpoint of one phase winding is grounded, the service conductor having the higher phase voltage-to-ground shall be durably and permanently marked by an outer finish that is ______ in color, or by other effective means, at each termination or junction point.

A. orange > 230.56 B. red C. blue D. any of these

Where it is unlikely that two or more non-coincidental loads will be in use simultaneously, only the ______ the loads used at one at one time

A. smaller of B. largest of > 220.60 C. difference between D. none of these

Additional services shall be permitted for a single building or other structure sufficiently large to make two or more services necessary if permitted by ______.

A. the registered design professional B. special permission > 230.2(C)(3) C. the engineer of record D. master electricians

Type S fuses shall be classified at not over 125V for the following ampacity ranges except ______.

A. 0-15A B. 16-20A C. 21-30A D. 31-40A > 240.53(A)

Grounding electrodes of the rod type less than ______ in. in diameter shall be listed.

A. 1/2 B. 5/8 > 250.52(A)(5)(b) C. 3/4 D. 1

A bare 4 AWG copper conductor installed horizontally near the bottom or vertically, and within that portion of a concrete foundation or footing that is in direct contact with the earth, can be used as a grounding electrode when the conductor is at least ______ ft in length.

A. 10 B. 15 C. 20 > 250.52(A)(3) D. 25

Grounding electrode conductors ______ AWG and larger that are not exposed to physical damage can be run along the surface of the building construction without metal covering or protection.

A. 10 B. 8 C. 6 > 250.64(B)(1) D. 4

Ground-fault protection of equipment shall be provided for solidly grounded wye electrical systems of more than 150 volts-to-ground, but not exceeding 1,000V phase-to-phase for each individual device used as a building or structure main disconnecting means rated ______ or more, unless specifically exempted.

A. 1000A > 240.13 B. 1500A C. 2000A D. 2500A

Underground service conductors that supply power to limited loads of a single branch circuit shall not be smaller than ______.

A. 14 AWG Copper B. 14 AWG Aluminum C. 12 AWG Copper > 230.31(B)Ex D. 12 AWG Aluminum

Sign and outline lighting outlets shall be calculated at a minimum of ______ volt-amperes for each required branch circuit specified in 600.5(A).

A. 150 B. 180 C. 600 D. 1200 > 220.14(F)

For feeder installations consisting of not more than two-2-wire branch circuits, the building disconnecting means shall have a rating of not less than ______.

A. 15A B. 20A C. 25A D. 30A > 225.39(B)

Plate electrodes shall be installed not less than ______ below the surface of the earth.

A. 18" B. 30" > 250.53(F) C. 4ft D. 8ft

When a ground ring is used as a grounding electrode, it shall be buried at a depth below the earth's surface of not less than ______.

A. 18in B. 24in C. 30in > 250.53(F) D. 8ft

Where rock bottom is encountered when driving a ground rod at an angle up to 45°, the electrode can be buried in a trench that is at least ______ deep.

A. 18in B. 30in > 250.53(4) C. 4ft D. 8ft

When sizing a feeder for the fixed appliance loads in dwelling units, a demand factor of 75 percent of the total nameplate ratings can be applied if there are ______ or more appliances fastened in place on the same feeder.

A. 2 B. 3 C. 4 > 220.53 D. 5

The recommended maximum total voltage drop on branch circuit conductors is ______ %.

A. 2 B. 3 > 210.19(A)Note3 C. 4 D. 6

Underground service conductors shall be protected from damage in accordance with ______ including minimum cover requirements.

A. 240.6(A) B. 300.5 > 230.32 C. 310.15(B)(16) D. 430.52

Where used outside, aluminum or copper-clad aluminum grounding electrode conductors shall not be terminated within ______ of the earth.

A. 6in B. 12in C. 15in D. 18in > 250.64(A)

The conductors used to connect the surge protective device to the line or bus and to ground shall not be any longer than ______ and shall avoid unnecessary bends.

A. 6in B. 12in C. 18in D. necessary > 285.12

A premises wiring system supplied by a grounded AC service shall have a grounding electrode conductor connected to the grounded service conductor at ______.

A. The load side of the service disconnect B. The feeder disconnecting means C. Each service > 250.24(A) D. All of these

A three-phase, 4-wire, ______ power system used to supply power to nonlinear loads may necessitate that the power system design allow for the possibility of high harmonic currents on the neutral conductor.

A. Wye connected > 210.4(A)Note 1 B. Delta connected C. Wye/Delta connected D. none of these

The continuity of a grounded conductor shall not depend on a connection to ______.

A. a metallic enclosure B. a raceway C. cable armor D. any of these > 200.2(B)

Outside feeder tap conductors can be of unlimited length without overcurrent protection at the point they receive their supply if the tap conductors ______ .

A. are suitably protected from physical damage B. terminate at a single circuit breaker or a single set of fuses that limits the load to the ampacity of the conductors C. both of these > 240.21(B)(5) D. neither of these

Overcurrent devices are not permitted to be located in the bathrooms of ______.

A. dwelling units B. dormitories C. guest rooms or guest suites of hotels or motels D. all of these > 240.24(E)

The grounded conductor of an alternating-current system operating at 1,000V or less shall be routed with the ungrounded conductors and connected to each disconnecting means grounded conductor terminal or bus, which is then connected to the service disconnecting means enclosure via a(n) ______ that is installed between the service neutral conductor and the service disconnecting means enclosure.

A. equipment bonding conductor B. main bonding jumper > 250.24(C) C. grounding electrode D. intersystem bonding terminal

______ shall not be used as grounding electrodes.

A. metal underground gas piping systems B. aluminum C. both of these > 250.52(B)(1)(2) D. none of these