NEC Chapter 2: Wiring and Protection
Multiwire branch circuits must supply only ________________ loads . Ex 1 : A multiwire branch circuit can supply an individual piece of line - to - line utilization equipment , such as a range or dryer .Ex 2 : A multiwire branch circuit can supply both line - to - line and line - to - neutral loads if the circuit is protected by a device such as a multipole circuit breaker with a common internal trip that opens all ungrounded conductors of the multiwire branch circuit simultaneously under a fault condition
line-to-neutral
48. Surge arrestors 1,000V or less are also known as Type 1 surge protective devices (SPDS). (a) True (b) False
(a) True 285.1 Note
22. Where fuses are used as the service overcurrent device, the disconnecting means shall be located ahead of the load side of the fuses in accordance with 230.91. (a) True (b) False
(b) False 230.91
38. Grounding electrode conductors of the wire type shall be _______. (a) solid (b) stranded (c) insulated or bare (d) any of these
(d) any of these 250.62
Conductors are considered outside of a building when they're installed :
1) Under not less than 2 in . of concrete beneath a building. 2) Within a building within a raceway encased in not less than 2 in . of concrete or brick. (3) In a vault that meets the construction requirements of Article 450 , Part III. (4) In a raceway not less than 18 in . below a building. (5) Within rigid or intermediate metal conduit that passes directly through an eave but not a wall of a building.
34. Where more than one concrete-encased electrode is present at a building or structure, it shall be permitted to bond only one into the grounding electrode system. (a) True (b) False
(a) True 250.52(A)(3)
9. For other than dwelling occupancies, banks, or office buildings, each receptacle outlet shall be calculated at not less than _______ VA (a) 90 (b) 180 (c) 270 (d) 360
(b) 180 220.14(I)
16. 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 (c) the engineer of record (d) master electricians
(b) special permission 230.2(C)(3)
25. 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) a and b (d) none of these
(c) a and b 240.21(B)(5)
A ________________ must be installed within 25 ft of heating , air-conditioning and refrigeration equipment [ 210.63 ] .
15A or 20A , 125V receptacle outlet
Multiple Receptacle Rating . If connected to a branch circuit that supplies two or more receptacles, the receptacles must have an ampere rating in accordance with the values listed in Table ________________.
210.21(B)(3)
10. 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) two (b) three (c) four (d) five
(c) four 220.53
15. For 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
(d) 30A 225.39(B)
Although the NEC doesn't require a specific color code for ungrounded conductors , electricians often use the following color system for power and lighting conductor identification: 120/240V, single-phase: ________________ 120/208V, three-phase: ________________ 120/240V, three-phase: ________________ 277/480V, three-phase: ________________
120/240V, single-phase: black, red, and white 120/208V, three-phase: black, red, blue, and white 120/240V, three-phase: black, orange, blue, and white 277/480V, three-phase: brown orange , yellow , and gray or , brown , purple , yellow , and gray
The Code recognizes that not all luminaires will be on at the same time and it permits the following demand factors to be applied to the general lighting load as determined in Table ________________ .
Table 220.42
Every article in Chapter 2 deals with a different aspect of correctly sizing and protecting circuits. This differs from the purpose of Chapter 3 , which is to ________________.
correctly install the conductors that make up those circuits
As you go through Chapter 2 , remember its purpose . It's primarily concerned with ________________ .
correctly sizing and protecting circuits.
Number of Branch Circuits . The minimum number of general lighting and general-use receptacle branch circuits must be determined by ________________.
dividing the total calculated load in amperes by the ampere rating of the circuits used.
For the application of 210.8 (A)(7) ,210.8(A)(9) , and 210.8(B)(5), distance measured as the shortest path the flexible cord would follow without ________________.
piercing a floor , wall , ceiling , or fixed barrier , or passing through a door doorway , or window.
The NEC doesn't permit the use of white or gray conductor insulation for ________________ conductors within a raceway , even if the conductors are permanently reidentified.
ungrounded
Each multiwire branch circuit must have a means to simultaneously disconnect all ________________ at the point where the branch circuit originates.
ungrounded conductors
19. Underground service conductors shall be protected from damage in accordance with _______ including minimum cover requirements. (a) 240.6(A) (b) 300.5 (c) 310.15(B)(16) (d) 430.52
(b) 300.5 230.32
32. High-impedance grounded neutral systems shall be permitted for three-phase ac systems of 480V to 1,000V where _______. (a) the conditions of maintenance and supervision ensure that only qualified persons service the installation (b) ground detectors are installed on the system (c) line-to-neutral loads are not served (d) all of these
(d) all of these 250.36(1), (2), and (3)
1. 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
(d) any of these 200.2(B)
50. 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) 6 in. (b) 12 in. (c) 18 in. (d) necessary
(d) necessary 285.12
45. The Code requires the installation of an equipment grounding conductor of the wire type in _______. (a) rigid metal conduit (RMC) (b) intermediate metal conduit (IMC) (c) electrical metallic tubing (EMT) (d) none of these
(d) none of these 250.118(2), (3), and (4)
The terminal for the grounded [ neutral ] conductor must be colored white ( ________________ ). The terminal for the ungrounded conductor must be a color readily distinguishable from white ( ________________ ) . Terminals for the circuit equipment grounding conductor must be ________________ [ 250.126 and 406.10 ( B ) ] .
silver brass or copper green
23. Ground-fault of equipment shall be 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) 1,000A (b) 1,500A (c) 2,000A (d) 2,500A
(a) 1,000A 240.13
13. A demand factor of _______ percent applies to a multifamily dwelling with ten units if the optional calculation method is used. (a) 43 (b) 50 (c) 60 (d) 75
(a) 43 220.84 and Table 220.84
39. Grounding electrode conductors that are not subject to physical construction if securely fastened to the surface on which it damage can be run exposed along the surface of the building is carried. (a) True (b) False
(a) True 250.64(B)
49. Surge protective devices shall be marked with a short-circuit current rating and shall not be installed where the available fa current is in excess of that rating. (a) True (b) False
(a) True 285.7
There's ________________ limit to the number of receptacles permitted on a circuit in a dwelling unit .
no limit
Bathroom Branch Circuit . At least one 20A , 120V branch circuit is required to supply the bathroom(s) receptacle outlet(s) as required by 210.52(D). This circuit isn't permitted to ________________.
serve any other outlet, such as bathroom lighting outlets or receptacles in other rooms
7. For the purposes of 210.71, examples of rooms that are not meeting rooms include _______. (a) auditoriums (b) schoolrooms (c) coffee shops (d) all of these
(d) all of these 210.71(A) Note 2
26. Overcurrent devices are not permitted to be located in the bath- rooms of _______. (a) dwelling units (b) dormitories (c) guest rooms or guest suites of hotels or motels (d) all of these
(d) all of these 240.24(E)
8. Where fixed multioutlet 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 (b) 5½ (c) 6 (d) 6-1/2
(a) 5 220.14(H)(1)
37. 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) 18 in. (b) 30 in. (c) 4 ft (d) 8 ft
(b) 30 in. 250.53(G)
5. 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 (d) 24
(c) 18 210.52(A)(3)
33. 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 (d) 25
(c) 20 250.52(A)(3)
6. The receptacle outlet required for indoor electrical service equipment shall not be required to be installed for _______. (a) multifamily occupancies (b) assembly occupancies (c) one- and two-family dwellings (d) equipment pits
(c) one- and two-family dwellings 210.64
17. Service-drop conductors shall have _______. (a) sufficient ampacity to carry the load (b) adequate mechanical strength (c) a or b (d) a and b
(d) a and b 230.23(A)
41. Where service equipment consists of more than one enclosure, grounding electrode conductor connections shall be permitted to be _______. (a) multiple individual grounding electrode conductors (b) one grounding electrode conductor at a common location (c) a common grounding electrode conductor and taps (d) any of these
(d) any of these 250.61(D)(1), (2), and (3)
46. When ungrounded circuit conductors are increased in size to to the increase in size of the ungrounded conductor shall be proportionately increased in size according conductors using their _______. (a) ampacity (b) circular mil area (c) diameter (d) none of these
(b) circular mil area 250.122(B)
12. Where it is unlikely that two or more noncoincident loads will be in use simultaneously, only the _______ the loads used at one time is required to be used in computing the total load to a feeder. (a) smaller of (b) largest of (c) difference between (d) none of these
(b) largest of 220.60
30. 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 (c) grounding electrode (d) intersystem bonding terminal
(b) main bonding jumper 250.24(C)
18. 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 (d) 12 AWG aluminum
(c) 12 AWG copper 230.31(B) Ex
20. Service-entrance conductors can be spliced or tapped by clamped or bolted connections at any time as long as _______. (a) the free ends of conductors are covered with an insulation that is equivalent to that of the conductors or with an insulating device identified for the purpose (b) wire connectors or other splicing means installed on conductors that are buried in the earth are listed for direct burial (c) no splice is made in a raceway (d) all of these
(d) all of these 230.46
11. To determine the feeder calculated load for ten 3 kW household cooking appliances, use _______ of Table 220.55. (a) Column A (b) Column B (c) Column C (d) none of these
(a) Column A 220.55 and Table 220.55
2. 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 i entire length on other than green insulation. (a) 8 (b) 6 (c) 4 (d) 3
(b) 6 200.6(A)(1),(2), and (3)
40. 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 (d) 4
(c) 6 250.64(B)(1)
4. 120V, single-phase, 15A and 20A branch circuits supplying outlets and devices installed in guest _______ of hotels and motels shall be protected by any of the means described in 210.12(AY1) through (6). (а) гоoms (b) suites (c) a and b (d) none of these
(c) a and b 210.12(C)
28. Ungrounded alternating-current systems from 50V to 1,000V or less that are not required to be grounded in accordance with 250.20(b) shall have _______. (a) ground detectors installed (b) the ground detection sensing equipment connected as close as practicable to where the system receives its supply (c) a and b (d) ground-fault protection for equipment
(c) a and b 250.21(B)(1) and (2)
44. Lightning protection system ground terminals _______ be bonded to the building or structure grounding electrode system. (a) shall (b) shall not (c) shall be permitted to (d) none of these
(c) shall be permitted to 250.104(D)(2) Ex 1
27. 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 the voltage-to-ground during normal operation (c) facilitate overcurrent device operation in case of ground faults (d) a and b
(d) a and b 250.4(A)(1)
24. Single-pole breakers with identified handle ties can be used to protect each ungrounded conductor for line-to-line connected Ioads. (a) True (b) False
(a) True 240.15(B)(2) and (3)
47. A grounded circuit conductor is permitted to ground noncurrent- carrying metal parts of equipment, raceways, and other enclosures on the supply side or within the enclosure of the ac service disconnecting means. (a) True (b) False
(a) True 250.142(A)(1)
31. When supplying a grounded system at a separate building or structure, an equipment grounding conductor shall be run with the supply conductors and connected to the building or structure disconnecting means and to the grounding electrode(s). (a) True (b) False
(a) True 250.32(B)(1)
42. Ferrous metal raceways and enclosures for grounding electrode conductors shall be electrically continuous from the point of attachment to cabinets or equipment to the grounding electrode. (a) True (b) False
(a) True 250.64(E)(1)
43. A separate bonding jumper to the building structural metal shall not be required if the metal frame of a building or structure is used as the _______ for the separately derived system. (a) bonding jumper (b) ground-fault current path (c) grounding electrode (d) none of these
(a) bonding jumper 250.106
21. 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 (b) red (c) blue (d) any of these
(a) orange 230.56
3. 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 (b) delta-connected (c) wye/delta-connected (d) none of these
(a) wye-connected 210.4(A) Note 1
14. 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) 12 in. (b) 18 in. (c) 2 ft (d) 5 t
(b) 18 in. 225.19(A) Ex 3
35. Grounding electrodes of the rod type less than _______ in. in diameter shall be listed. (a) 1/2 (b) 5/8 (c) 3/4 (d) 1
(b) 5/8 250.52(A)(5)(b)
36. _______ shall not be used as grounding electrodes. (a) Metal underground gas piping systems (b) Aluminum (c) Metal well casings (d) a and b
(d) a and b 250.52(B)(1) and (2)
29. Ungrounded alternating-current systems from 50V to less than 1,000V shall be legibly marked "Caution: Ungrounded System- Operating _______ Volts Between Conductors" at _______ of the system, with sufficient durability to withstand the environment involved. (a) the source (b) the first disconnecting means (c) every junction box (d) a or b
(d) a or b 250.21(C)
