2008 NEC Review Practice Test 1 PDF

2008 NEC Review PracticeTest 1 1. In Class 1, Division 1 locations, conduit seals shall be placed a maximum of ______inches from an enclosures containing arc producing equipment. a) 12 b) 18...

2008 NEC Review PracticeTest 1 1. In Class 1, Division 1 locations, conduit seals shall be placed a maximum of ______inches from an enclosures containing arc producing equipment. a) 12 b) 18 c) 24 d) 30 ## CORRECT --> Conduit seals shall be installed within 18 in. from the enclosure. Only explosionproof unions, couplings, reducers, elbows, capped elbows, and 2. What length is required for the pullbox in the diagram below? The box is used with 480 volt conductors that are not spliced. a) 32 inches b) 24 inches c) 48 inches d) any length ## CORRECT --> In straight pulls, the length of the box shall not be less than eight times the trade diameter of the largest raceway. If conductors are spliced the box shall be at least 6 times 2 inches long or 12 inches per 314.28(A)(2) 3. What is the load that can be used for the service calculation for a dwelling unit when the Range has a nameplate rating of 13 KW? a) 13 kw b) 8.4 kw c) 8 kw d) none of the above ## CORRECT --> 8 kw + 5 percent of 8 kw is 8.4 kw. 4. What size copper equipment grounding conductor is required for a circuit protected with a 50 ampere circuit breaker? a) No. 12 copper b) No. 10 copper ## CORRECT --> Table 250-122 lists a No. 10 copper for a 50 ampere circuit breaker. 5. What is the highest voltage permitted for a Class 1 power limited circuit? a) 1,000 volts b) 30 volts c) 24 volts d) ## CORRECT --> Class 1 power limited circuits shall be supplied from a source that has a rated output of not more than 30 volts and 1000 volt-amperes. 6. What is the missing voltage in the sketch below? a) 120 volts b) 120 volt's c) 1200 volts ## CORRECT --> 120/Voltage = 100 /1000; Voltage = (120 x 1000 )/ 100, Voltage = 1200 volts 7. What is the minimum size 10 feet long Rigid Metal conduit required for the following 9 conductors? 4 THWN #12 CU, 2 RHW (covered) #8 CU, 3 RHW (covered) #6 CU a) 1 1/2 inch b) 2 inch c) 1 1/4 inch Problem: What size Rigid Metal conduit is permitted for the following 9 conductors? 4 THWN #12 CU, 2 RHW (covered) #8 CU, 3 RHW (covered) #6 CU From Table 5: Area of #12 THWN is.0.133 x 4 =.0532 Area of # 8 RHW covered =.0835 x 2 =.167 Area of #6 RHW covered =.1041 x 3 =.3123 Total area =.5325 sq. inches In Table 4 for Rigid Metal Conduit find the first number larger than.5325 that is 0.610 in column for over 2 wires 40%. This corresponds to 1 1/4 inch conduit. 8. What is the efficiency of a motor which draws 4.5 kilowatts from the line and delivers 5 horsepower? a) 80 percent b) 83 percent c) 90 percent ## CORRECT --> efficiency = (5 x 746 watts) / 4,500 watts 9. Power Factor can be defined as: True Power divided by Apparent Power a) Apparent Power divided by True Power b) Apparent Power divided by volts x amperes c) ## CORRECT --> True Power = watts, Apparent power=volt-amperes. PF = watts/ volt amperes 10. What is the power factor for a three phase system operating when the wattmeter reads 6,000 watts, the voltmeter reads 208 volts, and the ammeter reads 20 amperes? a).90 or 90 percent b) 1.04 or 104 percent c).83 or 83 percent ## CORRECT --> PF = 6,000 / (208*20*1.732) 11. What is the power factor for a 8000 watt load connected to a 240 volt AC single-phase circuit if the current is 36 amperes? a).8 or 80 percent b).93 or 93 percent c) 1.0 or 100 percent ## CORRECT --> PF = 8,000 / (240 volts x 36 amperes) 12. For the figure below if No. 4 or larger conductors are installed in the raceways dimension X shall be ____inches minimum. The box is used for splices and doe not have the cubic inch dimensions marked on it. a) 18 inches b) 16 inches c) 24 inches ## CORRECT --> Use larger of (6 x 3) + 3 +3 = 24 inches or (6 x 2) + 2 + 1 + 1 = 16 inches. Dimension X shall be 24 inches.  For the 4-way Switch, which is the correct hookup? 13. a) D to T, E to R, F to T, G to S b) D to S, E to R, F to T, G to W c) D to R, E to T, F to S, G to W 14. A dwelling has a floor area of 2200 sq. ft., exclusive of an unfinished cellar not adaptable for future use, unfinished attic, and open porches. Appliances are a 12-kW range and a 5.5-kW, 240-V dryer. Assume range and dryer kW ratings equivalent to kVA ratings in accordance with Sections 220-18 and 220-19.Computed Load [see Section 220-10] Fill in the following information: General Lighting Load: _____ sq. ft. at __ VA per sq. ft. =_______ VA Minimum Number of Branch Circuits Required: General Lighting Load: ______ VA / 120 V = ___ A General Lighting Load: ______ VA / 120 V = ___ A This requires______ 15-A, 2-wire or______ 20-A, 2-wire circuits Small Appliance Load: _____ 2-wire, 20-A circuits Laundry Load :One 2-wire, 20-A circuit One additional bathroom 20 ampere circuit is also required. Minimum Size Feeder Required : General Lighting _______ VA Small Appliance ______ VA Laundry ______ VA Total 11100 VA ______ VA at 100% 3000 VA _______ VA - 3000 VA =______ VA at _____% is ______ VA Net Load _______ VA Range ______ VA Dryer________ VA Net Computed Load _______ VA Net Computed Load for 120/240-V, 3-wire, single-phase service or feeder ________ VA / 240 V = ______ A Net computed load exceeds 10 kVA. Would require service conductors to be _____ A. Calculation for Neutral for Feeder and Service: Lighting and Small Appliance Net Load _____ VA Range: _____ VA at 70% is 5600 VA Dryer : _______ VA at 70% is ______ VA Total ________ VA Computed Load for Neutral: __________ VA / 240 V = ______ A What is the final computed load for the neutral in the above load calculation? a) 65.9 b) 63.7 c) 100 d) 111 Solution This dwelling has a floor area of 2200 sq. ft., exclusive of an unfinished cellar not adaptable for future use, unfinished attic, and open porches. Appliances are a 12-kW range and a 5.5-kW, 240-V dryer. Assume range and dryer kW ratings equivalent to kVA ratings in accordance with Sections 220.18 and 220.19. Computed Load [see Section 220.10] General Lighting Load: 2200 sq. ft. at 3 VA per sq. ft. = 6600 VA Minimum Number of Branch Circuits Required [see Section 210-11(e)(1)] General Lighting Load: 6600 VA / 120 V = 55 A This requires four 15-A, 2-wire or three 20-A, 2-wire circuits Small Appliance Load: Two 2-wire, 20-A circuits [see Section 210.11(C)(1)] Laundry Load:One 2-wire, 20-A circuit [see Section 210.11(C)(2)] Bathroom Branch Circuit: One 2-wire, 20-A circuit (no additional load calculation is required for this circuit) [see Section 210.11(C)(3)] Minimum Size Feeder Required [see Section 220.10] General Lighting 6600 VA Small Appliance 3000 VA Laundry 1500 VA Total 11100 VA 3000 VA at 100% 3000 VA 11100 VA - 3000 VA = 8100 VA at 35% is 2835 VA Net Load 5835 VA Range (see Table 220-19) 8000 VA Dryer (see Table 220-18) 5500 VA Net Computed Load 19,335 VA Net Computed Load for 120/240-V, 3-wire, single-phase service or feeder 19,335 VA ¸ 240 V = 80.6 A Net computed load exceeds 10 kVA. Section 230.42(B) would require service conductors to be 100 A. Calculation for Neutral for Feeder and Service Lighting and Small Appliance Net Load 5835 VA Range: 8000 VA at 70% (see Section 220.22) 5600 VA Dryer : 5500 VA at 70% (see Section 220-22) 3850 VA Total 14,550 VA Computed Load for Neutral 15,285 VA / 240 V = 63.7 A 15. The correct hookup for the 3-way switch below is: a) A to X, B to Z, C to Y b) A to Y, B to X, C to Z c) A to Z, B to Y, C to X d) A to Z, B to X, C to Y 16. Connect the delta wound 480 volt motor leads for the high voltage windings in the diagram below. a) 9-7, 4-6, 8-9, 5-4 b) 4-7, 5-8, 6-9 c) 4-9, 6-8, 5-7 17. Find the correct size ventilated cable tray for the diagram below. a) 6 inches b) 12 inches c) 18 inches d) 24 inches 18. Find the voltage across the 5 ampere load after the neutral is opened. Both loads are resistive and the power factor is 1.0. a) 180 volts b) 120 volts c 0 volts ## CORRECT --> R for 15 a load = 120/15 = 8 ohms; R for 5 a load = 120/5 = 24; Neutral open I = 240 /(8 + 24) = 7.5 a; E across 5 a load = 7.5 a x 24 = 180 volts 19. Find the size of inverse time circuit breaker required for the feeder protecting the following polyphase induction motors. These motors are Design B and have a Service Factor of 1.15 and are individually protected with inverse time circuit breakers. a) 150 ampere b) 175 ampere c) 200 ampere Solution Problem: Find the size of inverse time circuit breaker required for the feeder protecting the following polyphase induction motors. These motors are Design B and have a Service Factor of 1.15 and are individually protected with inverse time circuit breakers. This is a motor feeder circuit. There is a motor feeder Example D8 in Appendix D of the Code. Motor Circuit Conductors, Overload Protection, and Short-Circuit and Ground-Fault Protection (see Sections 240.6, 430.6, 430.22, 430.23, 430.24, 430.32, 430.34, 430.52, and 430.62, Tables 430.150 and 430.152) Feeder Short-Circuit and Ground-Fault Protection The rating of the feeder protective device is based on the largest branch-circuit protective device plus the sum of the full-load currents of the other motors [see Sections 240.6 and 430.62(A)]. For the 5-hp motor FLA is 7.6 amperes from Table 430.150. For the 15-hp motor FLA is 21 amperes from Table 430.150. For the 40-hp motor FLA is 52 amperes from Table 430.150. 52 x 1.25= 65 amperes 65 + 21 + 7.6 = 93.6 amperes The branch circuit protective device for the 40 hp motor is based on Table 430.152 is 250 percent times 52 = 130 amperes. By Section 240.6 the next larger standard size CB is 150 amperes. Then for the feeder Circuit Breaker: 150 + 21 + 7.6 = 178 amperes. The nearest standard fuse that does not exceed this value is 175 A [see Sections 240.6 and 430.62(A)]. Answer 175 ampere Circuit Breaker. 20. How many cubic inches is required for the following box? All conductors are No. 14 and there are no internal clamps. a) 12 cubic inches b) 16 cubic inches c) 18 cubic inches d) 20 cubic inches Problem: How many cubic inches is required for the following box? All conductors are No. 14 and there are no internal clamps. Conductor Count Switch = 2 Grounding conductors = 1 Conductors that originate outside the box and terminate or are spliced in the box = 5 Total= 8 The cubic inch area required by Table 314.16(B) for a No. 14 is 2 cubic inches. The cubic inch capacity required is 2 cubic inches x 8 or 16 cubic inches. Answer is 16 cubic inches. Reference: (b) Box Fill Calculations. The volumes in paragraphs (1) through (5), as applicable, shall be added together. No allowance shall be required for small fittings such as locknuts and bushings. (1) Conductor Fill. Each conductor that originates outside the box and terminates or is spliced within the box shall be counted once, and each conductor that passes through the box without splice or termination shall be counted once. The conductor fill, in cubic inches, shall be computed using Table 314.16(B). A conductor, no part of which leaves the box, shall not be counted. Exception: An equipment grounding conductor or conductors or not over four fixture wires smaller than No. 14, or both, shall be permitted to be omitted from the calculations where they enter a box from a domed fixture or similar canopy and terminate within that box. (2) Clamp Fill. Where one or more internal cable clamps, whether factory or field supplied, are present in the box, a single volume allowance in accordance with Table 314.16(B) shall be made based on the largest conductor present in the box. No allowance shall be required for a cable connector with its clamping mechanism outside the box. (3) Support Fittings Fill. Where one or more fixture studs or hickeys are present in the box, a single volume allowance in accordance with Table 314.16(B) shall be made for each type of fitting based on the largest conductor present in the box. (4) Device or Equipment Fill. For each yoke or strap containing one or more devices or equipment, a double volume allowance in accordance with Table 314.16(B) shall be made for each yoke or strap based on the largest conductor connected to a device(s) or equipment supported by that yoke or strap. (5) Equipment Grounding Conductor Fill. Where one or more equipment grounding conductors or equipment bonding jumpers enters a box, a single volume allowance in accordance with Table 314.16(B) shall be made based on the largest equipment grounding conductor or equipment bonding jumper present in the box. Where an additional set of equipment grounding conductors, as permitted by Section 250.146(D), is present in the box, an additional volume allowance shall be made based on the largest equipment grounding conductor in the additional set.  2008 NEC Review PracticeTest 2 1. In the diagram below the total resistance is _____ and the value of R3 is ____. a) 20, 10.7 ohms b) 20, 19.7 ohms c) 20, 20.7 ohms d) 10, 30 ohms 2. What is the ampacity of 12 No. 12 THHN copper conductors in a 10 feet long EMT raceway where there are 9 current carrying conductors and the ambient temperature is 42 degree C? (Select nearest answer) a) 10 amperes b) 15 amperes c) 18 amperes d) 22 amperes ## CORRECT --> The derating factor for 9 current carrying conductors in a raceway is 70 percent, and the ambient derating factor for 42 degrees C. is.87. 3. What is the allowable ampacity of each No. 6 THW copper conductor if there are 10 current carrying conductors in a 24 inch long rigid conduit nipple in a room where the ambient temperature is 55 degrees C? (Select nearest answer) a) 65 amperes b) 67 amperes c) 50 amperes d) 44 amperes ## CORRECT --> THW ampacity is 65 amperes. The ambient derating factor is.67.67 x 65 = 43.55 amperes 4. Find the size EMT nipple required to enclose 3 each 500 kcmil THHN conductors between two panels. a) 1 1/2 inch b) 2 inch c) 3 inch d) 3 1/2 inch ## CORRECT --> The area for 3 -500 kcmil THHN conductors is 3 x.7073 = 2.1219 For 60 percent fill using the.8 round off method requires a 2 inch EMT. 5. What size rigid steel conduit is required for 4 each 4/0 XHHW and 1 each No. 3 bare equipment grounding conductor if the raceway is 12 feet long? a) 1 1/2 inch b) 2 inch c) 2 1/2 inch d) 3 inch e) 1 inch ## CORRECT --> Area of 4 4/0 = 4 x.3197 = 1.2788; area of No. 3 is.053. 1.2788 +.053 = 1.3318 sq. in. requiring a 2 inch rigid conduit with a 40 6. Junction boxes shall be ______. a) accessible b) readily accessible c) visible d) inside removable panels ## CORRECT --> Conduit bodies, junction, pull, and outlet boxes shall be installed so that the wiring contained in them can be rendered accessible 7. The type of lampholder required in a branch circuit in excess of 20 amperes shall be ______. a) brass b) porcelain coated c) not an interchangeable type d) heavy duty ## CORRECT --> Where connected to a branch circuit having a rating in excess of 20 amperes, lampholders shall be of the heavy-duty type. 8. Unless an excepted load as specified by the Code, a conductor rated 56 amperes shall be protected by a _____ fuse. a) 50 b) 60 c) 70 d) 80 ## CORRECT --> The next larger size permitted by Code is 60 amperes. 9. In a washdown area a metallic raceway shall be spaced not less than _____ inch from the walls. a) 1/8 b) 1/4 c) 1/2 d) 3/4 ## CORRECT --> Standard practice is to keep electrical equipment 1/4 inch of the surface in indoor locations that may become wet. 10. Given: Three (3) 500 kcmil Type THHN copper conductors in a raceway at 70 degrees C. The maximum allowable current in each conductor is _____ amperes. a) 249 b) 409 c) 430 d) 705 ## CORRECT --> By Table 310-16(bottom) the derating factor for 70 degrees C in the 90 degree C. column is.58..58 x 430 A. = 249 amperes. 11. A luminaire (fixture) that weighs more than _______ lb or exceeds 400 mm (16 in.) in any dimension shall not be supported by the screw shell of a lampholder. a) 4 b) 6 c) 50 d) 70 ## CORRECT --> Luminaires and lampholders shall be securely supported. A luminaire that weighs more than 6 lb or exceeds 16 in. in any dimension shall not be supported by the screw shell of a lampholder. 12. An AC-DC general use snap switch may be used with inductive loads at _____ percent of its ampere rating at the applied voltage. a) 40 b) 50 c) 70 d) 80 ## CORRECT --> A form of general-use snap switch suitable for use on either ac or dc circuits for controlling Inductive loads not exceeding 50 percent of the ampere rating of the switch. 13. When utilized as outside branch circuits and feeders, overhea conductors for 600 volts or less, for spans up to 50 feet, shall not be less than _____ copper. a) No. 14 b) No. 12 c) No. 10 d) No. 8 ## CORRECT --> Open individual conductors shall not be smaller than the following: For 600 volts, nominal, or less, No. 10 copper or No. 8 aluminum for spans up to 50 ft (15.2 m) in length and No. 8 copper or No. 6 aluminum for a longer span, unless supported. 14. Conductors of light and power systems of 600 volts or less may occupy the same enclosure, without regard to whether the individual circuits are AC or DC, only where all the conductors are ________. a) insulated for the maximum temperature within the enclosure. insulated for the maximum voltage applied to any conductor within the enclosure b) c) insulated for the maximum of 300 volts d) none of the above 15. When utilized in overhead services, without any exceptions, conductors shall not be smaller than No. ______ copper. a) 14 b) 12 c) 10 d) 8 ## CORRECT --> The conductors shall not be smaller than No. 8 copper or No. 6 aluminum or copper-clad aluminum. 16. Made electrodes shall have a resistance to ground not to exceed ______ ohms when used alone. a) 5 b) 10 c) 25 d) 30 ## CORRECT --> A single electrode consisting of a rod, pipe, or plate that does not have a resistance to ground of 25 ohms or less shall be augmented by one additional e 17. Disregarding all exceptions, the sum of the cross-sectional area of all conductors in a metal wireway shall not exceed ______ percent of the interior cross-sectional area of the wireway. a) 20 b) 30 c) 40 d) 60 ## CORRECT --> The sum of cross-sectional areas of all contained conductors at any cross section of the wireway shall not exceed 20 percent of the interior cross- sectional area of the wireway. 18. Given: Nine (9) No. 8 AWG THHN copper conductors in a conduit at 30 degrees C. What is the maximum allowable ampacity in each conductor? a) 33.3 b) 38.5 c) 40.0 d) 55 ## CORRECT --> By Table 310.15(b)(2)(a) the derating factor for 9 conductors in a raceway is 70%..70 x 55 = 38.5 amperes. 19. The minimum total circuit ampacity required to supply an air conditioning motor compressor unit which consumes 8,500 volt amperes of power at a line voltage of 240 volts is ______ amperes. Select the closest answer. a) 44.3 b) 40.0 c) 35.4 d) 28.3 ## CORRECT --> I = P/E = 8500 VA/ 240 volts = 35.4 amperes. From Table 440.32 125 per cent of 35.4 = 44.3 amperes. 20. Given: An office building has a required general lighting load of 50,000 volt amperes. The general lighting load is supplied by a single phase, 230 volt feeder circuit. The minimum calculated current in the feeder circuit ungrounded (hot) conductors is _____ amperes. Select the closest answer. a) 208 b) 217 c) 227 d) 230 ## CORRECT --> I = P / E; 50,000 / 240 volts = 208 amperes.  2008 NEC Review Practice Test 3 1. Given: Three (3) 500 kcmil THHN conductors in a raceway at 70 degrees F. What is the maximum allowable current in each conductor if the terminations and equipment is rated at 90 Degrees C? a) 345 b) 380 c) 430 d) 447 ## CORRECT --> The correction factor at the bottom of Table 310-16 for 70 degrees F.is 1.04 for 90 degree rated insulation such as THHN. 1.04 x 430 amperes = 447amperes. 2. Flexible cord may be used in all of the following locations except ______. a) hoists b) cranes c) to replace fixed wiring of a structure d) pendants 3. When a conduit nipple having a maximum length not to exceed 24 inches is installed, the nipple shall be permitted to be filled to _____ percent of its total cross sectional area. a) 30 b) 40 c) 50 d) 60 ## CORRECT --> Where conduit or tubing nipples having a maximum length not to exceed 24 in. (610 mm) are installed between boxes, cabinets, and similar 4. Drums of gasoline may be stored in what type of outdoor area? a) Anywhere b) Class III, Division 2 c) Class II, Division 1 d) Unclassified areas at a bulk storage plants. ## CORRECT --> This permission is given for bulk storage plants in Table 515.3 5. The interior of paint spray booths are considered ______. a) Class 1, or Class 2, Division 1 b) Class 1, Division 2 c) Class II, Division 2 d) Class II, Division 2 ## CORRECT --> The following spaces shall be considered Class I or Class II, Division 1 locations, as applicable: The interiors of spray booths and rooms. 6. The maximum allowable fill for conduit and tubing for 3 or more conductors, not lead covered is _______. a) 30% b) 40% c) 50% d) 60% ## CORRECT --> By Table 1 in Chapter 9, 40 percent. 7. In a conduit seal used in hazardous locations, the minimum thickness of the sealing compound, except where used in cables, should in no case be less than _______. a) 1/4" b) 1/2" c) 5/8" d) 3/4" ## CORRECT --> In a completed seal, the minimum thickness of the sealing compound shall not be less than the trade size of the sealing fitting and, in no case, less than 5/8 in. 8. Given: A 30 hp, 3-phase, 460 volt, continuous duty induction motor with a service factor of 1.15 and a temperature rise of 40 degrees C. The maximum rating of the required separate overload device is ______ amperes. a) 46 b) 50 c) 56 d) 60 ## CORRECT --> 125 percent of 40 is 50 amperes, but Section 430.32 allows a 140 percent maximum overload. 9. Given: Measurements for a 3-phase squirrel cage motor at full load are 460 volts and 65 amperes. Approximate the horsepower rating using the Code? a) 30 b) 40 c) 50 d) 60 ## CORRECT --> By Table 430.150 a 50 horsepower motor has a full load amperes of 65. 10. Refer to the figure below. Given the circuit shown. What is the current in the neutral conductor? a) 25.0 amperes b) 12.5 amperes c) 6.25 amperes d) 4.2 amperes ## CORRECT --> Current through 1000 watt load = 1,000/120 =8.3 amperes; Current through 500 watt load = 500/120 = 4.17 amperes. 8.3 - 4.1 = 4.2 amperes. Z 11. Given: A 25 foot feeder tap. The ampacity of the tap must be at least ____ that of the feeder conductor or overcurrent protection from which it is tapped. a) 1/4 b) 1/3 c) 1/2 d) 3/4 ## CORRECT --> Also, the tap conductors shall terminate in a single circuit breaker or a single set of fuses that will limit the load to the ampacity of the tap conductors and shall be protected. 12. The normal current allowed on a copper bus in an Auxiliary Gutters is 1,000 amperes per square inch. The number of amperes which a 2 1/2 x 1/4 inch square copper bus may carry under these conditions is _____ amperes. a) 625 b) 750 c) 1,000 d) 1,250 ## CORRECT --> Amperes = (2.5 x.25) x 1,000= 625 amperes 13. Given: A 240 volt conductor has a total length of 500 feet and supplies a load of 10 amperes. The conductor has a resistance of 1.45 ohms per 1,000 feet. The total voltage drop in the conductor circuit conductors is _____ percent. Select the closest answer. a) 3 b) 5 c) 7 d) 12 ## CORRECT --> E=IxR; E=10 x (500/1,000)x 1.45 = 7.25 volts; percent =(7.25/240 ) x 100 = 3 percent 14. The maximum fixture weight that may be supported by the screw shell of a lampholder is _____ pounds. a) 2 b) 6 c) 10 d) 16 ## CORRECT --> A fixture that weighs more than 6 lb (2.72 kg) or exceeds 16 in. (406 mm) in any dimension shall not be supported by the screw shell of a lampholder. 15. Where a cable is installed through bored holes in wood joists, where possible, the holes shall be bored so that the edge of the hole is not less than ______ inch(es) from the nearest edge of the wood member. a) 1 b) 1 1/4 c) 1 1/2 d) 2 ## CORRECT --> If this requirement cannot be met, listed *nail plates* can be used. 16. The minimum lighting load required for the general lighting (only) of a church building having outside dimensions of 100' by 200' is ______ volt-amperes. a) 2,000 b) 4,000 c) 20,000 d) 40,000 ## CORRECT --> 100` x 200` = 20,000 sq. ft.,By Table 220.12 1 VA per square foot is required for churches. 1 x 20,000 =20,000 VA. 17. The minimum size copper equipment grounding conduct for grounding equipment having a 40 ampere automatic overcurrent device in the circuit ahead of the equipment is No. _____. a) 6 b) 8 c) 10 d) 12 ## CORRECT --> By Table 250-122 a 40 ampere OCPD requires a No. 10 copper equipment grounding conductor. 18. Given: A 240 volt, 20 ampere two wire branch circuit. If the maximum allowable voltage drop through the circuit conductors is 2.4 volts, what is the maximum allowable resistance of the circuit conductors? a) 12 ohms b) 1.2 ohms c) 0.48 ohms d) 0.12 ohms ## CORRECT --> R= E/ I; R= 2.4/ 20; R =.12 ohms. The 240 volts is used for calculating percent voltage drop which in this case is (2.4/240 )x 100 = 1 percent. 19. The combined load of two, 230 volt fixed heaters on a 30 ampere 230 volt branch circuit in a dwelling occupancy shall not exceed _____ kilowatts. Select the closest answer. a) 2.4 b) 5.5 c) 5.9 d) 24.0 ## CORRECT -->.8 x 30 = 24 amperes. 24 x 230 = 5520 watts; 5520/1000= 5.5 kw. 20. Outlet boxes mounted in combustible walls or ceilings must be mounted so that they will be set back not more than a maximum of _____ inch from the finished surface. a) 1/2 b) 1/4 c) 1/8 d) 0 (must be flush or project therefrom) ## CORRECT --> In walls and ceilings constructed of wood or other combustible material, boxes shall be flush with the finished surface or project there from.  2008 NEC Review Practice Test 4 1. Refer to the figure below. What is wrong with the grounding rod installation illustrated below (Assume the rod could not be driven because of a a rock bottom)? a) It is not 10 feet long. b) The ground rod shall be 5/8 inches in diameter c) It is not 30 inches deep d) There is nothing wrong, according to the Code ## CORRECT --> Where rock bottom is encountered, the electrode shall be driven at an oblique angle not to exceed 45 degrees from the vertical or shall be buried in a trench that is at least 2½ ft (762 mm) deep. Which of the following is not a standard fuse or inverse time circuit breaker size? 2. a) 35 b) 45 c) 50 d) 55 ## CORRECT --> 50 amperes and 60 amperes are standard fuse and circuit breaker sizes but 55 is not. 3. In general, a continuous duty motor rated at more than 1 horsepower shall be protected by a separate overload device rated at no more than ______ percent of the motor nameplate full- load current rating. a) 75 b) 100 c) 115 d) 125 4. Where direct buried conductors or cables emerge from the ground they shall be protected by enclosures or raceways. In no case shall the protection be required to exceed ______ inches below finished grade. a) 12 b) 18 c) 24 d) 30 ## CORRECT --> Direct-buried conductors and cables emerging from the ground shall be protected by to a point at least 8 ft above finished grade. In no case shall the protection be required 5. Given: Three resistors (R1, R2, and R3) are installed in a series circuit. The power used by R1 is 100 watts and the power used by R2 is 75 watts. The total power used by the circuit is 225 watts. Then the power used by resistor R3 is _____ watts. a) 24 b) 50 c) 75 d) 175 ## CORRECT --> 225 - 75 - 100 = 50 watts 6. Refer to the figure below. The total resistance Rt is ______ ohms. Select the closest answer. a) 9.4 b) 10.5 c) 15 d) 40 ## CORRECT --> Basic electrical theory. Rt = (R1 x R2)/ (R1 + R2); RT = (25 x 15) / (25 +15) = 9.4 ohms 7. Given: A free standing electric range is rated 120/240 volts and requires a neutral connection for the 120 volt timer and lights. The range is equipped with 3 wire cord with No. 8 copper conductors and a 3 prone plug for two hot leads and neutral. The range frame shall be permitted to be _______. grounded by running a ground from the range frame to the outlet box, wrapping the a) ground around the cord and then grounding it to the outlet box. b) ungrounded grounded by a 4-wire cord containing the two hot leads, the neutral, and a green c) grounding conductor. (the range requires a 4-wire cord) d) grounded at the range by bonding the grounded conductor to the range frame. ## CORRECT --> A new change no longer allows ranges to be grounded with he grounded conductor in new installations. 8. In dwelling units a multi-wire branch circuit supplying more than one device on the same yoke shall be protected by _______. a) two (2) single pole circuit breakers, operating independently b) two (2) single pole circuit breakers, tied together c) one (1) non-fused single pole disconnect only d) one (1) fuse only ## CORRECT --> In dwelling units, a multiwire branch circuit supplying more than one device or equipment on the same yoke shall be provided with a means to disconnect simultaneously all ungrounded conductors at the panelboard where th 9. The Code requires at least two small appliance branch circuits for dwellings. These small appliance circuits shall be assigned a load of _______ volt-amperes each when calculating feeders and service entrance requirements. a) 750 b) 1000 c) 1500 d) 2000 ## CORRECT --> In each dwelling unit, the load shall be computed at 1500 volt- amperes for each 2-wire small-appliance branch circuit required by Sections 210.11(C)(1) and 220.52(A) 10. Which of the following receptacles may be connected to the small appliance circuits? a) receptacles for electric clocks in the kitchen b) garage ceiling receptacles for garage door openers c) hallway receptacles which are close to the kitchen d) living room receptacles ## CORRECT --> Also the small appliance branch circuits can supply Receptacles installed to provide power for supplemental equipment and lighting on gas-fired ranges, ovens, or counter-mounted cooking units. 11. A metal underground water pipe in direct contact with the earth for at least 10 feet has traditionally been a preferred grounding electrode. For all new construction, a metal underground water pipe is _______. a) still the preferred grounding electrode, by itself, when available. still an acceptable grounding electrode, but it must be supplemented by at least one b) additional grounding electrode. c) no longer accepted as a grounding electrode accepted as the only grounding electrode when buried at least three(3) feet below the d) surface. ## CORRECT --> Because plumbers keep replacing metal pipe with plastic pipe the metal underground water pipe is no longer a reliable underground grounding electrode. 12. Thermal insulation shall not be installed within _____ inches of a recessed light fixture enclosure unless the recessed light fixture is identified as suitable for direct contact with insulation. a) 2 b) 3 c) 4 d) 5 ## CORRECT --> Thermal insulation shall not be installed above a recessed fixture or within 3 in. (76 mm) of the recessed fixture*s enclosure, wiring compartment, or ballast unless it is identified for contact with insulation, Type IC. 13. The No. 12 or 14 grounded conductor of a branch circuit shall be identified by a ______ wire. white or gray color or three continuous white stripes on other than green insulation. a) b) green color or bare copper c) yellow color d) black color ## CORRECT --> An insulated grounded conductor of No. 6 or smaller shall be identified by a continuous white or natural gray outer finish or by three continuous white stripes on other than green insulation along its entire length. 14. The Code defines "continuous load" as a load where the maximum current is expected to continue for at least _______. a) one hour or more b) two hours or more c) three hours or more d) twenty four hours a day ## CORRECT --> Continuous Load: A load where the maximum current is expected to continue for 3 hours or more. 15. For calculating the maximum number of conductors allowed in an outlet box the volume required for each No. 12 conductor is _____ cubic inches. a) 2 b) 2.25 c) 2.5 d) 3 ## CORRECT --> No. 2 requires 2.25 cubic inches per Table 314.16(B) 16. Outlet boxes mounted in non-combustible walls or ceilings must be mounted so that they will be set back not more than a maximum of _____ inch from the finished surface. a) 1/8 b) 1/4 c) 1/2 d) 3/4 17. Screw-shell lampholders shall be wired so that the ______ conductor is connected to the screw-shell. a) grounding b) grounded c) ungrounded d) bare ## CORRECT --> For devices with screw shells, the terminal for the grounded conductor shall be the one connected to the screw shell. 18. Metal enclosures for overcurrent devices in damp or wet locations shall be mounted so there is at least ______ inch air space between the wall or other support surface. a) 1/8 b) 1/4 c) 3/8 d) 1/2 19. Are least ______ inches of free conductor shall be left at each outlet and switch point for splices or for the connection of fixtures or devices. a) 5 b) 6 c) 7 d) 8 ## CORRECT --> At least 6 in. (152 mm) 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 for splices or the connection of fixtures or devices. 20. In determining load on the volt-ampere per square foot basis the _______the building shall be used for each floor. a) outside dimensions of b) inside dimensions of c) height of d) number of rooms in ## CORRECT --> The floor area for each floor shall be computed from the outside dimensions of the building, dwelling unit, or other area involved.  2008 NEC Review Practice Test 5 1. The circuit conductor that is defined as being intentionally grounded is the _______ conductor. a) grounding b) grounded c) equipment grounding d) grounding electrode ## CORRECT --> Grounded Conductor. A system or circuit conductor that is intentionally grounded. 2. Class II location are those that are hazardous because of the presence of ________. a) ignitable vapors b) ignitable fibers c) combustible dust d) combustible liquids ## CORRECT --> Class II locations are those that are hazardous because of the presence of combustible dust. 3. If three resistors with values 5, 10, and 15 ohms respectively are connected in parallel, the combined total resistance is ____ ohms. Select the closest answer. a) 0.4 b) 2.3 c) 2.7 d) 30.0 ## CORRECT --> For the 5 and 10: (5 x 10) / (5 + 10)= 3.3: 3 in parallel with 15 is (15 x 3.3) / 15 + 3.3) = 2.7 ohms 4. The wiring in a 200 foot long branch circuit measures a total resistance of 0.5 ohms. What is the resistance per 1,000 feet? a) 0.5 ohms b) 1.0 ohms c) 2.5 ohms d) 5.0 ohms ## CORRECT --> 1000 is 5 times 200 so resistance is 5 x.5 = 2.5 ohms 5. The maximum total voltage drop on both feeders and branch circuits to the farthest outlet should not exceed ____ percent of the supply voltage. a) 2 b) 3 c) 4 d) 5 ## CORRECT --> 5 percent total: 2 percent for feeders or 3 percent for branch circuits. 6. The working space in front of enclosed equipment operating at a voltage of 480 volts must have a width of a least ______ inches. a) 42 b) 30 c) 36 d) 20 ## CORRECT --> In general the work space shall be at least 30 inches wide, 3 feet deep and 6 1/2 feet high 7. For dwelling units, the Code requires a minimum of _______ for the kitchen small appliance load. a) one 15 ampere b) two 15 ampere circuits c) one 20 ampere circuit d) two 20 ampere circuits ## CORRECT --> In addition to the number of branch circuits required by other parts of this section, two or more 20-ampere small-appliance branch circuits shall be provided. 8. Generally, equipment grounding conductors No. 6 and smaller shall be identified by ______. (select best answer) a) green color unless it is bare b) green color with one or more yellow stripes unless it is bare c) bare conductor bare or Individually covered or insulated equipment grounding conductors shall have a d) continuous outer finish that is either green or green with one or more yellow stripes except as permitted in this section. e) All of the above 9. Rod and pipe grounding electrodes shall not be less than ____ feet in length. a) 6 b) 7 c) 8 d) 10 ## CORRECT --> Rod and pipe electrodes shall not be less than 8 ft (2.44 m) in length 10. Every dining room of a dwelling unit requires receptacle outlets to be installed so that no point along the floor line in any wall space more than _____ feet, measured horizontally, from an outlet. a) 6 b) 7 c) 8 d) 10 ## CORRECT --> In every kitchen, family, dining, recreation, living room, parlor, library, den, sunroom, bedroom, receptacle outlets shall be installed so that no point along the floor line in any wall space is more than 6 feet from an receptacle. 11. Open runs of Listed liquidtight flexible nonmetallic conduit installed in lengths longer then ____ feet shall be secured every ____ feet. a) 6, 3 b) 6, 4 1/2 c) 6, 66 d) 10, 10 ## CORRECT --> Liquid tight flexible nonmetallic conduit shall be securely fastened at intervals not exceeding 3 ft (914 mm) and within 12 in. (305 mm) on each side of every outlet box, junction box, cabinet, or fitting. 12. Generally, noncurrent-carrying metal parts of electrical equipment should be kept at least ____ feet away from lightning rod conductors in air and 3 feet from lightning conductors in concrete, or shall be bonded to the lightning conductors. a) 3 b) 4 c) 5 d) 6 ## CORRECT --> Separation from lightning protection conductors is typically 6 ft (1.83 m) through air or 3 ft (0.92 m) through dense materials such as concrete, brick, or wood. 13. Branch-circuit conductors supplying a single motor which operates under continuous duty shall have an ampacity not less than ____ percent of the motor full-load current rating. a) 100 b) 115 c) 125 d) 140 ## CORRECT --> Branch-circuit conductors that supply a single motor used in a continuous duty application shall have an ampacity of not less than 125 percent of the motor’s full-load current rating as determined by Section 430.6(A). 14. The maximum number of overcurrent devices (other than those provided in the mains) in a single cabinet of a lighting and appliance panelboard ___________. (select the best answer) a) is 30 b) is 36 is no longer limited. The quantity of overcurrent devices is limited to design and c) listing of the panel board. is 42 ## CORRECT --> Aside from the second exception to 408.36, the maximum of 42 overcurrent devices was deleted for the 2008 Code. Now the quantity of overcurrent devices is limited to design and listing of the panel board. 15. Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum branch-circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity not less than the noncontinuous load plus ______ percent of the continuous load. a) 65 b) 80 c) 125 d) 200 ## CORRECT --> There is an exception: Where the assembly, including the overcurrent devices protecting the branch circuit(s), is listed for operation at 100 percent of its rating, the allowable ampacity of the branch circuit conductors shall be permitted to be not less than the sum of the continuous load plus the noncontinuous load. 16. Liquid-tight flexible metal conduit may be used in _____. a) areas that are both exposed and concealed b) areas that are subject to physical damage c) 4 1/2 inch trade size d) 5 inch trade size ## CORRECT --> Liquid tight flexible metal conduit shall not be used as follows: Where subject to physical damage Where any combination of ambient and conductor temperature will produce an operating temperature in excess of that for which the material is approved. 17. The maximum size of flexible metallic tubing that may be used in any construction or installation is _____. a) 3/8" b) 1/2" c) 3/4" d) 1" ## CORRECT --> This seems very small, but it is what the Code says. The Minimum Bend Radii is 17 1/2 inches! 18. Where conductors of less than 600 volts emerge from the ground they shall be protected by enclosures or raceways that extend from below grade to a point at least ____ feet above finished grade. a) 4 b) 6 c) 8 d) 10 19. The total number of quarter bends allowed in one run of rigid nonmetallic conduit shall not exceed ____. a) 2 b) 3 c) 4 d) 5 ## CORRECT --> The standard for almost any raceway is no more than 4 quarter bends or the equivalent in degrees (360 degrees) between outlets. A quarter bend = 90 degrees. 20. Where ungrounded conductors of minimum size No. _____ or larger enter a raceway in a cabinet, the conductors shall be protected by an insulated fitting. a) 3 b) 4 c) 6 d) 5 ## CORRECT --> Where raceways containing ungrounded conductors No. 4 or larger enter a cabinet, box enclosure, or raceway, the conductors shall be protected.  2008 NEC Review Practice Test 6 1. Fountains that have water common to a swimming pool do not need to comply with all of the swimming pool requirements. a) True b) False 2. At swimming pools an intentional bond of a minimum conductive surface area of 9 square inches shall be installed in contact with the pool water. This bond shall be permitted to consist of parts that are required to be bonded in 680.26(B). a) True b) False 3. Metal parts of forming shells for Wet-Niche swimming pool luminaires in contact with pool water are not permitted to be made of brass. a) True b) False 4. The minimum depth for any underwater lighting fixture is 18 inches below water unless listed otherwise. a) True b) False ## CORRECT --> Wall-Mounted Luminaires (Fixtures). Luminaires (lighting fixtures) mounted in walls shall be installed with the top of the luminaire (fixture) lens not less than 450 mm (18 in.) below the normal water level of the pool, unless the luminaire (lighting fixture) is listed and identified for use at lesser depths. No luminaire (fixture) shall be installed less than 100 mm (4 in.) below the normal water level of the pool. 5. GFCI protection is required for any branch circuit that supplies underwater fixtures operating at over 15- volts. a) True b) False 6. Receptacles located within 20 feet of the inside walls of a swimming pool require GFCI protection. a) True b) False 7. A storable swimming pool must not have any dimension over 12 feet. a) True b) False 8. In a data-processing room the control for the disconnecting means shall be grouped and identified and shall be readily accessible at the principal exit doors. a) True b) False 9. A disconnecting means must be provided for all data-processing equipment in a information technology equipment room. a) True b) False 10 Type NM cables are permitted to connect data-processing equipment by under floor wiring.. a) True b) False 11 The bottom of a sign must be at least 12 feet above an area accessible to vehicles.. a) True b) False 12 Electric signs using incandescent lamps must be marked with the number of lampholders.. a) True b) False 13 A lighting fixture is permitted in a clothes closet if an 18-inch clearance is maintained from the storage. area. a) True b) False 14 An AC general use snap switch must not be used to control a tungsten-filament lamp loads.. a) True b) False 15 Junction boxes must be accessible.. a) True b) False 16 A duplex receptacle in a box reduces the number of allowed conductors by two.. a) True b) False 17 Edison-base fuses are acceptable for new installations.. a) True b) False  Flexible metallic tubing may not be used in lengths over 5 feet. 18. a) True b) False 19. EMT installed in the ground in cinder concrete must have a protective layer of noncinder concrete at least 2 inches thick. a) True b) False 20 The largest size NM cable has No. 2 copper conductors or No. 2 aluminum conductors.. a) True b) False  2008 NEC Review Practice Test 7 1. Type MV cable is rated 2,001-volts or higher. a) True b) False ## CORRECT --> Type MV cable is a single or multiconductor solid dielectric insulated cable rated 2001 volts or higher. 2. Open wiring on insulators above 6 feet from the floor does not require protection. a) True b) False ## CORRECT --> Conductors within 7 ft (2.13 m) from the floor shall be considered exposed to physical damage. 3. Cable tray systems must not be used in hoist ways. a) True b) False ## WRONG --> Cable tray systems shall not be used in hoist ways or where subject to severe physical damage. 4. Flexible metal conduit may be used to protect conductors emerging from the ground and run on a pole. a) True b) False ## CORRECT --> Direct-buried conductors and cables emerging from the ground shall be protected by enclosures or raceways extending from the minimum cover distance required by Section 300.5(D)(1) below grade to a point at least 8 ft (2.44 m) above finished grade. 5. Under normal conditions, direct buried cables must be buried at least 24 inches. a) True b) False ## CORRECT --> In general the requirement is 24 inches with many other depths given. 6. A No. 6 copper conductor in a vertical raceway must be supported at least every 80 feet. a) True b) False 7. Conductors of size No. 1 for general use may not be run in parallel. a) True b) False ## CORRECT --> Aluminum, copper-clad aluminum, or copper conductors of size No. 1/0 and larger, comprising each phase, neutral, or grounded circuit conductor, shall be permitted to be connected in parallel (electrically joined at both ends to form a single conductor). 8. A connection of a No. 8 conductor to a terminal can be by means of a pressure connector or solder lug. a) True b) False ## CORRECT --> Connection of conductors to terminal parts shall ensure a thoroughly good connection without damaging the conductors and shall be made by means of pressure connectors (including set- screw type), solder lugs, or splices to flexible leads. Connection by means of wire-binding screws or studs and nuts that have upturned lugs or the equivalent shall be permitted for 10 AWG or smaller conductors. 9. At least 4 Inches of free conductor must be left at each outlet to connect luminaires. a) True b) False ## CORRECT --> 6 inches, not 4 inches. 10. Holes in studs for cables must be in the center and not less than 1 inch from the nearest edge of the stud. a) True b) False ## CORRECT --> By Section 300.4(A)(1) the edge of holes must be 1 1/4 inches from nearest edge. 11. The smallest fixture wire permitted by the Code is size No. 18. a) True b) False 12. Flexible cords may not be used if they are concealed behind building walls, ceilings or floors. a) True b) False 13. When six current-carrying conductors are installed in a raceway, the maximum load current of each must be reduced to 70 per cent. a) True  b) False ## CORRECT --> 80 percent, not 70 percent. See the Table. 14. A No. 14 grounded conductor in a circuit must have a white or gray color. a) True b) False ## CORRECT --> There are other rules, too. 15. A feeder tap less then 25 feet long requires overcurrent protection if the ampacity of the tap conductors is at least one-third of the ampacity of the feeder conductors. a) True b) False 16. A conductor in a general circuit with an ampacity of 735-amperes may be protected by an 800-ampere fuse. a) True b) False 17. A three-phase air conditioner must be directly connected to a recognized wiring method and not by flexible cord. a) True b) False ## CORRECT --> A room air conditioner that is rated three phase or rated over 250 volts shall be directly connected to a wiring method recognized in Chapter 3, and provisions of Art 440 Part G shall not apply. 18. An attachment plug and receptacle may disconnect cord-connected household refrigerating equipment. a) True b) False 19. Type AC cable must not be used to connect motors to their supply. a) True b) False 20. The frames of stationary motors supplied by metal-enclosed wiring must be grounded. a) True b) False