Chapter 115

80

For residential circuits, a good rule to follow is to never load a branch circuit to more than ___ percent of the rating.

600

For residential wiring, not less than one 15-ampere lighting branch circuit should be provided for every ___ square feet of floor area.

37.5

What is the total cubic inch capacity of three 3" × 2" × 2 1/2" device boxes ganged together?

plaster ring

When a switch is to be installed in a 4 11/16" square (2100 or 411) box, a(n) ___ must be installed on the box.

All of these: -the brakes shall be set -wheel chocks shall be used -outriggers shall be used if provided

When operating an aerial lift on an incline, ___.

manufacturer-provided anchor points on the lift

When working in an aerial lift, you are required to tie off. It is permitted to tie off to ___.

Any of these: -2-Gang 2 1/2" deep masonry box -3 1/2" deep masonry box -1 1/2" deep 4"-SQ box -1 1/4" deep 4 11/16"-SQ box

Which of the following boxes could be used for three each 10 AWG and six each 12 AWG conductors?

is not permitted

A pendant luminaire mounted in a clothes closet ___.

the two "hot"

Section 210.11(B) in the NEC® requires that loads be evenly proportioned (or balanced) among the different circuits in a panelboard. This means that when everything connected to all circuits is ON then the current in ___ feeder conductors are equal, or as close as possible.

more

Since I = E ÷ R lamp then a lamp that is operated at 130 volts will draw ___ current than when operated at 120 volts.

True

Sometimes volt-amps (VA) can be larger than watts (W) (True or False)

you have written permission from the manufacturer

Aerial lifts can be modified for the current job if ___.

2

Although not limited to 80% by the NEC®, if 20-amp residential circuits are to be loaded only up to their ratings, how many 20-ampere, 120-volt circuits will be required? The homeowner wants fifteen 150 watt light fixtures and twenty 75 watt fixtures.

5

How many number 12 AWG conductors may be installed in a 4" × 2 1/8" × 1 7/8" device box?

2

How many single receptacles can be installed in a two-gang box that is made using two single-gang boxes that are ganged together?

2 1/2"

A group of five metal switch boxes are ganged together to form a 5-gang box. The box assembly is to have three single-pole switches and two three-way switches installed. The following conductors enter the box assembly: six ungrounded conductors (includes "travelers"), five grounded conductors, three switch legs, and five grounding conductors. Also, five cable clamps are contained in the assembly. All the conductors are 12 AWG. Each of the ganged boxes will have to be 3" × 2" × ___.

2 1/2

A light switch and a fan switch are to be installed in one 2-gang box. For this box assembly, you will use two 3" x 2" metal device (switch) boxes that you will gang together to form the 2-gang box. The cables entering the box are 12 AWG with ground Type MC cables. A 12-2 feeds power to the box assembly and a 12-3 exits the box assembly to supply the fan/light. The cable clamps are external type clamps. The minimum size switch boxes you will use for this installation are 3" × 2" × ___".

4507

A piece of equipment has a fixed resistance of 9.6 ohms. How much power will the equipment deliver when connected to a 208-volt circuit?

open

A series circuit consists of a power source, circuit conductors, and a lamp. If the filament in the lamp is broken, this circuit is called a(n) ___ circuit.

arc-fault circuit interrupter

Convenience receptacles that are installed in bedrooms in a house are required to be protected by a(n) ___.

none of these: -stand on the middle safety rail -use a step as long as it is 6" or less -use a 4' step ladder

If the aerial lift is short of the desired work height, it is permissible to ___ as long as you are tied off.

There is a flexible wiring method with a separate grounding conductor.

It is permitted to make a surface extension from a cover fastened to a concealed box if which of the following conditions exist?

4

How many number 10 AWG conductors may be installed in a 3" × 2" × 2" device box?

All of these: -National Electrical Code requirements -economy - minimizing the number and length of circuits -convenience for the homeowner or other user

Residential wiring plans generally show lighting and receptacle outlet locations but not circuits. The electrician should design the installation with which of the following in mind: ___.

series

The duct heater contains two heating elements that are connected as shown. Each of the two elements is rated to deliver 1850 watts whenoperated at 125 volts. See Figure 115.317. This is a ___ circuit.

0

The duct heater contains two identically-rated heating elements that are connected as shown. See Figure 115.312. If the leads of a voltmeter were placed on T3 & T2, the meter should indicate ___ volts.

208

The duct heater contains two identically-rated heating elements that are connected as shown. See Figure 115.312. If the leads of the voltmeter were moved to T1 & T4, the meter should indicate ___ volts.

120

The duct heater contains twoidentically ratedheating elements that are connected as shown. See Figure 115.311. If the leads of a voltmeter were placed on T3 & T4, the meter should indicate ___ volts.

greater than

The required minimum clearances for surface-mounted incandescent or LED luminaires installed in clothes closets are ___ those for fluorescent luminaires.

5.45

This duct heater contains two heating elements that are connected as shown. The fixed or "hot" resistance of each of the two elements is 22 ohms. See Figure 115.314. What is the total current drawn by the duct heater when connected to the 240-volt circuit?

104

See Figure 115.316. The voltage dropped across each element when the boiler is connected to the 208-volt circuit is ___ volts.

Above certain electric baseboard heaters

Where are electrical receptacle outlets not permitted to be located?

Either I nor II

A shallow box is shown at I and a deep box is shown at II in Figure 115.105. One of these 3-gang masonry boxes will have several EMT conduits connected to it. The box will contain three 3-way switches.Nine 14 AWG "travelers" are pulled into the box along with four 12 AWG circuit conductors. Additionally, a 12 AWG grounding conductor is installed. All conductors are copper THHN/THWN. The box shown at ___ will have sufficient volume for this installation. Select one: -I only -II only -either I nor II -neither I nor II

1

A wire nut is used to connect a grounding conductor that enters a box to another grounding conductor that exits the box. Then a pigtail is connected under the wire nut and goes to a receptacle in the box. For calculating conductor fill, these grounding conductors count as ___ conductor(s).

It=I1=I2=I3

Current in a series circuit of three resistive elements uses which formula?

240

Each heating element has the same power and voltage ratings as the other three. Refer to the pictorial circuit shown in Figure 115.333. If the leads of a voltmeter are placed on T5 and T8, the meter should indicate ___ volts.

All lamps would go out

If lighting fixtures are connected in series, what happens if one of the lamps burns out?

45

The 3-gang masonry box shown in Figure 107.458 will have several EMT conduits connected to it. The EMT will be the equipment grounding conductor - NO ground wires will be pulled in. The box will contain three 4-way switches. Twelve "travelers" are pulled into the box along with two other circuit conductors. All conductors are 12 AWG copper THHN/THWN. The box must have a minimum volume of ___ in3.

35.6

The 4" square (1900 or Raco 232) box shown in Figure 107.433 is 21/8" deep. A 3/4" rise plaster ring (also shown) is installed on the box and will add a volume of 5.3 in 3. This volume is found stamped into the plaster ring. Using the box volume per the NEC®, the total volume of the assembly with the p-ring installed on the box is ___.

44

This duct heater contains twoheating elements that are connected as shown. The fixed or "hot" resistance of each of the two elements is 22 ohms. See Figure 115.314. What is the total resistance of the duct heater (both elements)?

increases

As more loads are added to a series circuit, the resistance of the circuit ___.

True

Installing receptacles back-to-back on opposite sides of a wall within the same "stud space" offers the advantage of making the installation easier and cheaper. However, if the wall is fire rated, back-to-back installation might violate the Code unless fire-rated "putty" or fire-rated "listed" boxes are used. (True or False)

24.75

Refer to Figure 107.456. The minimum volume required for this box is ___ in 3. Each of the three Type NM cables contains a ground. The "pigtails" to the receptacle are 12 AWG wires. As you can see, the cable connectors are external (outside the box).

9.17

Refer to the pictorial circuit shown in Figure 115.337. The current flowing through each circuit conductor is ___ amps.

3 1/2

Two 3" × 2" metal device (switch) boxes are ganged together to form a 2-gang box. A light switch and a fan switch are to be installed in this 2-gang box assembly for a ceiling fan/light kit. A 12-3 cable is run from the panel to the 2-gang box. One circuit feeds power to the switches and the other circuit is connected to a 12-2 cable that supplies power to a receptacle box on the same wall. A 12-3 cable exits the box assembly to supply the fan/light. The cable clamps are of the external type. All cables are Type AC with ground. The shallowest switch boxes you can use for the 2-gang box assembly are 3" × 2" × ___" deep.

12 watts

What is the total power used by a 12-volt circuit having two 6 watt loads connected in series?

4 11/16 x 1 1/2 square

Which of the following metal boxes could be used for one single-pole light switch (connected to 12 AWGs), six each 14 AWG conductors, four each 12 AWG conductors, and two cable clamps?

I only

Which of the pictorial drawings, shown below, shows all four elements connected in series through the terminal strip? Select one: -I only -II only -Both I & II -Neither I nor II

is not

Using a wire nut, a neutral that enters a box is connected to another neutral that exits the box. A pigtail is also connected under the wire nut and goes to a receptacle in the box. This pigtail ___ counted in the box fill calculation per 314.16(B)(1).

160.8

Where a piece of equipment is connected to a 2-pole breaker in a 120/240-volt 3Ø, 4-wire panel, each circuit conductor to the equipment will have to carry ___ amps of current. The equipment has a nameplate rating of 38.6 KVA @ 240 volts 1-ph.

13

At 180 VA per outlet, how many outlets can be installed on a 20-ampere circuit (120 volt) if the circuit loading is to remain within its ratings?

offers the advantage that all power in a room will not go out if the overcurrent protective device trips

Many electricians wire the lights and receptacles in a room on different circuits because this ___.

No

Refer to partial circuit plan shown in Figure 115.103. You are required to size the box that will contain a split-wired receptacle. If the cables entering this box were all #12 MC cables, could a 3" × 2" × 3½" deep metal device (switch) box be used here? The MC cables will be connected to the box using external connectors. There are NO cable clamps within this box. Hint: don't forget to count the wires for the device and the ground(s) that are in the MC cable.

RT=R1+R2+R3

Resistance in a series circuit of three resistive elements uses which formula?

314.16(B)(4)

Section ___ of the NEC® states that for each yoke or strap, containing one or more devices or equipment, a double volume allowance shall be made.

1 1/2

Refer to partial circuit plan shown in Figure 115.103. You are required to size the box that will contain a split-wired receptacle. If the cables entering this box were all #12 MC cables, what is the smallest 4" square (1900) metal box that could be used here? The box will have a 1"-rise plaster ring installed that adds a volume of 6.1 in3 to the total volume. The MC cables will be connected to the box using externalconnectors. There are NO cable clamps within this box. Hint: don't forget to count the wires for the device and the ground(s) that are in the MC cable.

314.24

Calculating and providing the proper volume of a box is not always enough. Section ___ of the NEC® states outlet and device boxes shall be deep enough so that conductors will not be damaged when installing wiring devices or equipment.

60

Calculations should not include any power requirements for the blower motor in the FBU. The nameplate on the FBU indicates that it will deliver a total of 11.2 kW of heat when the supply circuit is 250 volts. Refer to the illustration of the FBU and the information shown with Figure 115.342.Whenthe supply circuit is exactly240volts, the voltage applied to Element 4 (E4) is ___ volts.

30.0

Refer to Figure 115.104. The minimum volume required for this box is ___ in3. The Type NM cables each contain grounds. You will install asecond receptacle in this box. A flat (0.0 in3 volume) p-ring is used. The "pigtails" to both of the receptacles are #12 wires. As you can see, the cable connectors are external (outside the box).

does not

The NEC® ___ specify the maximum number of lighting fixtures that can be connected to a 120-volt branch circuit in a dwelling.

an unspecified number of

The NEC® allows ___ receptacle outlets to be connected on a 120-volt residential lighting or small-appliance branch circuit.

25

The minimum cubic inch capacity of the j-box (shown in Figure 129.110) you could use where circuits A17-19 (2 "hots" + a neutral") enter the box is ___ in 3. The circuits are tapped and continue to feed other equipment or outlets. The wiring method is 10 AWG MC cable with a 10 AWG grounding conductor. All cable connectors are of the type that have locknuts to secure the connector to the box. The Equipment Grounding Conductor is NOT shown on the drawing.

the same as

The required minimum clearances for a recessed-mounted fluorescent luminaire installed in clothes closets are ___ those for a recessed-mounted incandescent or LED luminaire with a trim ring that has a glass lens.

II only

Top Picture: The heating elements are equally rated (same power and voltage). Bottom Picture: The schematic drawing, shown below at ___, is equal to the pictorial drawing shown in Figure 115.322. Select one: -I only -II only -both I & II -Neither I nor II

104

Two identical (same voltage and power ratings) heating elements are connected to a 2-pole 208-volt circuit breaker as shown. Refer to the pictorial circuit shown in Figure 115.315. If the leads of a voltmeter were placed on L1 and L2 on the lower element, the meter should indicate ___ volts.

208

Two identical (same voltage and power ratings) heating elements are connected to a 2-pole 208-volt circuit breaker as shown. Refer to the pictorial circuit shown in Figure 115.315. If the two voltmeter leads were placed on the breaker lugs, the meter should indicate ___ volts.