NEC CODE 2020
Separately derived systems rated ______ or less are not required to be grounded:
1 kVA NEC Code 250.30(A)(6)(b) Ex-2
Where a cable or raceway type wiring method is installed through bored holes in joist, rafters, or wood members, in both concealed and exposed locations, holes must be bored so that the edge of the hole is __________ in. or more from the nearest edge of the wood member. Where the distance is not possible, the cable or raceway must be protected from penetration by nails or screws by use of a steel bushing or plate, __________ in thick or more, and of the correct length and width installed to cove
1.25" | 0.0625"
Noncombustible surfaces that are broken or incomplete around boxes employing a flush-type cover or faceplate shall be repaired so there will be no gaps or open spaces larger than _____ in. at the edge of the box.
1/8
Motor feeder tap conductors not over ______ long must have an ampacity not less than one-tenth the rating of the feeder protection device:
10 ft, NEC Code 430.28(1)
If a single receptacle is installed on an individual branch circuit, it must have an ampere rating of not less than __________of the branch circuit.
100%
The feeder circuit for a mobile or a mobile or manufactured home must be rated at not less than ____ at 120/240V
100A NEC Code 550.33
The overcurrent device for the main marina feeder conductors must have ground fault protection not exceeding _____:
100mA NEC Code 555.3
Type MC cable containing four or fewer conductors, sized no larger than 10 AWG, shall be secured within _____ in. of every box, cabinet, fitting, or other cable termination.
12
For conductors on a branch circuit that supplies luminaires in a residence, what is the maximum allowable voltage between conductors on a branch circuit supplying luminaires in a residence?
120 volts
An electric heater having a capacity of _____ gallons or less is considered as continuous load for the purpose of sizing branch circuits:
120, NEC Code 422.13
A branch circuit for an appliance that's a continuous load must be rated not less than _____ of the marked ampere ratings of the appliance:
125%, NEC Code 210.19(A)(1)
If multiple power sources supply portable structures, the circuit equipment grounding conductors at each portable structures must be bonded together for all portable structures separated by less than ____:
12ft NEC Code 525.11
Flexible Metal Conduit (FMC) must be secured within _____ of each box, cabinet, conduit body or other termination:
12in, NEC Code 348.30(A)
Receptacles must be mounted ____ or more above the deck surface of the pier:
12in, NEC Code 555.19
In building over 3 floors. ENT must be concealed behind floors, walls, or ceiling that have a _____ minute finish rating:
15, NEC Code 362.10(2)
All ____ 125V receptacle outlets that are not a part of the permanent wiring of the building used by personnel must be GFCI protected:
15,20,30A
GFCI protection is required for ____, 125V, general purpose receptacles located in dirt confinement areas for livestock:
15A and 20A, NEC Code 547.5(G)(4)
Overhead conductors rating 600V or less, except for the conductors that supply the amusement ride or attractions, must have a clearance of _____ from portable amusement structures:
15ft, NEC Code 525.5(B)(1)
Cables listed for information technology equipment can be used to interconnect information technology equipment without the _____ cable length limited
15ft, NEC Code 645.5(B)(1)
How many #12 wires cna fit on a 3/4" EMT
16 per Table C.1 NEC code 2020
The coupling means of the Electric Vehicle supply equipment must be stored or located not less than _____ above the floor level:
18in, NEC Code 625.50
Which of the following is the minimum size of a single supply-side bonding jumper for three metal raceways with 300 kcmil service conductors each?
2 AWG- NEC Table 250.102(C)(1) For over 3/0 AWG and 350 kcmil the required bonding jumper size is 2 AWG
If internal combustion engines are used as the prime mover, an onsite fuel supply must be provided for not less than ______ of full demand operation of the system:
2 hours, NEC Code 701.12(B)(2)
______ circuit breakers or sets of fuses are acceptable as over current device to provide overload protection in one family dwellings:
2 to 6, NEC Code 230.90(A)
A two pole circuit breaker or fusible switch shall be considered as _____ over current devices:
2, NEC Code 408.54
The minimum lighting load for industrial commercial buildings is _____ volt amperes per square foot:
2, NEC Code Table 220.12
Maximum overcurrent protection for 12 AWG copper conductor is:
20 A NEC Code 240.4(D)
The overcurrent protection device of non-motor appliances must not exceed ________ if the overcurrent device rating is not marked:
20 A, NEC Code 422.11(E)(2)
The maximum number of conductors permitted in a wireway is limited to ______ of the cross sectional area of the wireway:
20%, NEC Code 376.22(A)
For equipment rated 800 A or more, personal doors located less than _____ from the nearest edge of the working space must open in the direction of egress and have listed panic hardware:
25ft, NEC Code 110.26(C)(3)
Power limited fire alarm circuit conductors must be separated by not less than _____ from insulated conductors of electric light, power or Class 1 circuits:
2in, NEC Code 760.136(G)
A flexible cord is permitted for an in-sink waste disposal if the cord length is no longer than _____:
3 ft NEC Code 422.16(B)(2)
Load where the maximum current is expected to exist for ______ hours or more is termed as continuous load:
3, NEC Code 100
What is the adjustment ampacity of a 3/0 THWN conductor in a wet location with an ambient temperature of 1080F? There are four 3/0 THWN conductors in the raceway.
3/0 THWN conductor ampacity in wet location (750C) = 175 Amperes ( NEC 310.15(B)(16)) Ambient temperature correction factor at 1080F = 0.85 ( NEC 310.15(B)(2)) raceway conductor bundle adjustment factor for 4 conductors= 0.8 ( NEC 310.15(B)(3)(a)) The conductor ampacity = 175 * 0.85 * 0.8 = 119 Amperes
Snap switches must not be ganged or grouped in enclosures with other receptacles, snap switches, or similar devices, unless they are placed so that voltage is __________ volts or less between adjacent devices, or unless placed in enclosures with securely installed, identified barriers between adjacent devices.
300 volts
Allowable ampacity for 10 AWG copper conductor is _______ in the 60o C Column:
30A, NEC Code 310.15(B)(16)
The overhead service conductors above a roof with a slope of at least 4.in in 12.in have a minimum clearance of ______:
3ft, NEC Code 230.24(A) exp-2
Electrical nonmetallic tubing must be secured within _____ of every box, cabinet or temperature fitting such as a conduit body:
3ft, NEC Code 362.30(A)
A cord no longer than ____ with an attachment plug and containing a copper equipment grounding conductor not smaller than 12 AWG is permitted for pool motors:
3ft, NEC Code 680.21(A)(5)
Except for storable pools, fixed or stationary equipment other than an underwater luminaire cord must not exceed ____ in length:
3ft, NEC Code 680.7
The ampacity adjustment factors don't apply to conductors installed in surface metal raceways if the cross sectional area of the raceway exceeds ______ :
4 sq.in NEC Code 386.22(1)
A switch or circuit breaker enclosure may be used as a raceway if the conductor fill doesnot exceed _____ :
40%, NEC Code 312.2
The maximum approval electrical trade size of IMC is ________ :
4in NEC Code 342.20(B)
Coaxial cables outside and entering buildings must have a separation of at least ____ from electric light, power, Class 1, or non power limited fire alarm circuit conductors not in raceway or cable:
4in, NEC Code 820.44(E)(1)
If installed horizontally, metal wireways must be supported at each end and at intervals not exceeding ______ :
5 ft, NEC Code 376.30(A)
Receptacles located more than _____ above the floor are not required to be tamper resistant:
5.5ft, NEC Code 406.12(C) Exp (1)
The total rating of a cord and plug connected room air conditioner must not exceed ______ of the rating of a branch circuit where lighting outlets, other appliances, or general use receptacles are also supplied
50%
What is the maximum of the ampere rating of the switch for general use snap switches supplying inductive loads, at the applied voltage?
50%
If space limitations prevent ____ of space from the pool, underground wiring must be installed in a complete raceway system:
5ft, NEC Code 680.10
The portion of the grounding electrode conductor that is the sole connection to one or more ground rod is not required to be larger than _____:
6 AWG, NEC Code 250.66(A)
All switches and circuit breakers used as switches shall be located so the operating handle, when in its highest position, is not more than __________ above the floor or working platform.
6 ft. 7 in.
A luminaire (fixture) that weighs more than __________ pounds or exceeds 16 inches in any dimension shall not be supported by the screw shell of a lampholder.
6 pounds
What is the minimum burial depth in inches, in a trench below 2 inch thick concrete or equivalent for residential branch circuits rated at up to 120 volts with GFCI protection and overcurrent protection of 20 amperes or less?
6"
The pit area in commercial garages, repair ans storage areas is classified as Class I, Division 2 if there is mechanical ventilation providing a minimum of _____ air changes per hour:
6, NEC Code 511.3(C)(3)(a)
Maximum distance to any receptacles shall be ______ along the floor line of any wall space measured horizontally:
6ft, NEC Code 210.52(A)(1)
Receptacles not supplying loads directly related to circulation systems must be located not less than _____ from the inside walls of the pool:
6ft, NEC Code 680.22(A)(3)
At least _____ of free conductor, measured from the point in the box where it emerges from its raceway or cable sheath shall be left at each outlet, junction and switch point:
6in, NEC Code 300.14
_____ is the maximum approved electrical trade size for PVC conduit:
6in, NEC Code 352.20(B)
A vertically mounted luminaire weighting no more than ______ can be supported to a device box or plaster ring secured to a device box:
6lb, NEC Code 314.27(A)(1) Exp-A
Paddle fans over _____ must be supported independently of the box:
70 lbs, NEC Code 422.18
Splices and taps must be accessible and must not fill raceway to more than _____ of its cross-sectional area:
75%
Cord and plug equipment not fastened in place cannot be rated more than ______ of the branch circuit rating:
80%, NEC Code 422.10(B)
Overhead communications cables must have a vertical clearance of at least _____ from all points of roofs above which they pass:
8ft, NEC Code 800.44(B)
An organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, an installation, or a procedure.
AHJ
What size service conductors are needed for a 190 A calculated load in a dwelling? The service disconnect breaker has a 200-amp rating.
Answer : 2/0 AWG Note : Service conductors that supply individual dwelling unit or single dwelling unit can have ampacity rating of 83% of service disconnect. The conductor ampacity for 200 A service disconnect = 0.83 * 200 = 166 amperes Refer : NEC Table 310.15(B)(16) 2/0 AWG with ampacity 175 amperes ( 750 C) is suitable as service conductor
Which of the following is allowed to be supplied by circuits not exceeding 120 volts, nominal, between conductors?
Auxiliary equipment of electric-discharge lamps. Cord-and-plug-connected or permanently connected utilization equipment The terminals of lampholders applied within their voltage ratings X-All of the above
Grounding type receptacles shall be used on which of the following branch circuits:
Both 15A or 20A, NEC Code 406.4(A)
A cord-and-plug-attached appliance is linked to a 25 ampere branch circuit. What is the maximum ampere rating that the appliance can handle?
Cord and plug connected equipment shall not exceed 80 percent of branch circuit rating 25 * 0.8 = 20 amperes
Ceiling grid which supports the wires may be permitted to support raceways:
False
A portable generator is required to be grounded if the generator only supplies receptacles mounted on the generator
False, NEC Code 230.54(A)
Flexible cords is permitted to be run through holes in walls, structural ceilings, suspended or dropped ceilings or floors:
False, NEC Code 400.8
The connected load of a single family dwelling unit is 4000 VA. The calculated demand load is which of the following?
First 3000 VA the demand factor is 100% = 3000 * 100 % = 3000 VA remaining (4000-3000) = 1000 ( demand factor = 35%) = 1000 * 0.35 = 350 VA total demand load = 3000 + 350 = 3350 VA
The capacity of the conductor is 150 amperes. If five conductors are placed in a flexible cord, what is the maximum conductor ampacity allowed for each conductor?
For 5 conductors in flexible cord allowed ampacity percentage = 80 % of rated amapcity Allowed amapcity of each conductor with 150 Ampere rating = 150 * 0.8 = 120 amperes.
A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an established period of time when a ground-fault current exceeds the values established for a Class A device.
Ground-Fault Circuit Interrupter (GFCI)
Box Fill Calculation
NEC code 2020 Index page 849 routes to 314.16B
What conductor size is needed for a single-family housing unit with an estimated load of 220 amps and a maximum unbalanced neutral load of 110 amps?
Service conductor for 225 Amperes load = 3/0 AWG neutral conductor for unbalanced load 110 = 3 AWG
The number of conductors permitted in LFNC shall not exceed the percentage fill specified in _____.
Table 310.16
What table is used for current values to determine the required ampacity of the branch circuit conductors to supply a 3-phase, continuous duty ac motor?
Table 430.250 of the NEC
A 1/0 THWN in a wet location has a rated ampacity of 150 amperes. If the same conductor is used at a temperature of 400 degrees Celsius. What is the corrected ampacity?
Temperature correction factor of 1/0 THWN Conductor for 40-750 C = 0.88 The corrected ampacity = 0.88 * 150 = 132 amperes
If the raceway contains four 1/0 THWN conductors, what is the ampacity of a 1/0 THWN conductor in a dry location at a temperature of 1040 F?
The conductor ampacity of 1/0 THWN in dry location ( 900C) = 170 amperes ( NEC Table 310.15(B)(16)) Ambient temperature correction factor at 1080F = 0.91 ( NEC Table 310.15(B)(2)) Raceway conductor bundle adjustment factor for 4 conductors = 0.8 ( NEC Table 310.15(B)(3)(a)) corrected ampacity = 170 * 0.8*0.91 = 124 amperes
The voltmeter at one end of the feeder reads 240 volts. What is the volt-minimum meter's reading voltage at the outlet of lighting loads?
The maximum voltage drop in feeder is 3 % the voltmeter reading = 240 - 0.03 * 240 = 240 - 7.2 = 232.8 volts
In a 3/4 EMT trade size, how many 10 AWG RHH conductors may be installed?
Total 6 10 AWG RHH conductors can be installed in trade size ¾ EMT.
A receptacle shall not be installed within, or directly over, a bathtub or shower space.
True
Direct-buried conductors or cables can be spliced or tapped without the use of splice boxes when the splice or tap is made in accordance with 110.14(B).
True
he ground detection sensing equipment must be connected as close as practicable to where the system receives its power supply:
True, NEC Code 250.12(C)
Of the following, which must be provided for a conductor of a size 4 AWG or larger entering a panelboard?
an insulated bushing
Electrical connections in marinas, boatyards, and commercial and noncommercial docking facilities, shall be located _____ unless the conductor splices for floating piers are contained within sealed wire connector systems listed and identified for submersion.
at least 12 in above the deck of a floating pier, fixed pier, and not below the electrical datum plane of a fixed pier
Ground-fault circuit-interrupter protection for personnel shall be provided for cables installed in electrically heated floors of _____.
bathrooms, hydromassage bathtub locations, kitchens
A(An) "_____" is a device, or group of devices, by which the conductors of a circuit can be disconnected from their source of supply.
disconnecting means
Working space distances for enclosed live parts shall be measured from the _____ of equipment or apparatus, if the live parts are enclosed.
enclosure or opening
Panelboards shall be required to have overcurrent protection, except for __________.
existing panelboards used for individual residency service equipment.
The conductors between the service equipment, a separately derived system, or other power supply and the final branch circuit overcurrent device:
feeder
When electrical installations are in hollow spaces, ventilation or air-handling ducts and vertical shafts, they must be made so the chance of spread of fire or other products of combustion will not be substantially increased. Openings around electrical penetrations through or into fire-resistant-rated ceilings, floors, partitions, or walls must be __________ with approved methods to maintain the existing fire-resistance rating.
firestopped
Unless listed for controlling other loads and installed accordingly, general-use dimmer switches may be used only for permanently installed:
incandescent luminaries
What do you call the midpoint on a single-phase, 3-wire system, or the common point on a wye-connection in a polyphase system, or a midpoint of a 3-wire, direct-current system, or midpoint of a single-phase portion of a 3-phase delta system?
neutral point
Wherever flexible cords with attachment plugs are to be used, a receptacle outlet must be installed, and where such cords may be permanently connected, then receptacles are __________ for the same type of cords.
permitted to be omitted
All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same __________.
raceway
Conductors for branch circuits that supply more than one receptacle for __________ loads must have an ampacity of at least the rating of the branch circuit.
ungrounded
