electrical

Pataasin ang iyong marka sa homework at exams ngayon gamit ang Quizwiz!

An inverter or an ac module in an interactive solar photovoltaic system shall _____ upon loss of voltage from the local utility company.

automatically de-energize its output

All exposed non-current-carrying metal parts of an information technology system shall _____ or shall be double insulated.

be bonded to the equipment grounding conductor

The purpose of an intersystem bonding termination is to provide a means for connecting _____ to the grounding electrode system.

bonding conductors for communications systems

In general, a motor disconnecting means must disconnect:

both the motor and controller.

determine the minimum number of 15-ampere, 120 volt, general lighting branch-circuits required for a dwelling with 2,600 square feet of habitable space

five

What is the MINIMUM number of 120-volt, 20-ampere, general lighting branch circuits required for a dwelling unit having a calculated lighting load of 9,600 VA?

four

In an underground installed rigid polyvinyl chloride conduit (PVC) system that consist of 50 feet length between pulling points, what is the MAXIMUM number of bends this run may have?

four (4) - 90 degree

Grounding conductors and bonding jumpers shall NOT be connected by _____.

sheet metal screws

The service disconnecting means for each electrical service shall consist of NOT more than _____ switches or circuit breakers, mounted in a single enclosure or in a group of separate enclosures.

six

In a health care facility, low voltage electrical equipment that is likely to become energized that is frequently in contact with the bodies of patients, shall operate on a voltage of _____ or less if the equipment is not approved as intrinsically safe, double-insulated or moisture-resistant.

10 volts

Determine the MAXIMUM overcurrent protection permitted for size 14 THWN copper motor control circuit conductors tapped from the load side of a motor overcurrent protection device. Given: the conductors require short-circuit protection and do not extend beyond the motor control equipment enclosure.

100 amperes

Determine the allowable ampacity of each size 12 AWG 75 deg. C rated copper conductor, where three (3) current-carrying conductors are in a common raceway with an ambient temperature of 125 deg. F.

16.75 amperes

Regardless of the applied voltage, or the type of insulation, size 12 AWG copper conductors require overcurrent protection NOT in excess of _____.

20 amperes

The NEC considers the area around the motor fuel dispensing pumps of a service station to be a hazardous location. This area extends a height of 18 inches above grade, and up to a distance from the enclosure of the outdoor motor fuel dispensing pumps of ____.

20 feet

What MINIMUM size 75°C copper feeder conductors are required to supply the following listed 3-phase, continuous-duty, 240-volt ac motors? one (1) 15 hp wound-rotor one (1) 7 hp induction-type one (1) 3 hp induction-type

4 AWG THWN

Where a conduit longer than 24 inches contains two (2) ungrounded conductors, one (1) grounded conductor and one (1) equipment grounding conductor, the conduit is permitted to be filled to a MAXIMUM of_____ of its cross-sectional area.

40 percent

Underground wiring is not permitted under a permanently installed swimming pool or within _____ of the pool, unless the wiring is supplying the associated pool equipment.

5 feet

A dry-type transformer of less than 1000 volts and _____ is permitted to be installed in a hollow space of a building, such as above an accessible lift-out ceiling, provided there is adequate ventilation.

50 kVA

For capacitors of over 1000 volts, a means shall be provided to reduce the residual voltage of a capacitor to _____ after the capacitor is disconnected from the source of supply.

50 volts or less within 5 minutes

For one-family dwellings and each unit of a two-family dwelling, at least one 125-volt, single-phase, 15- or 20-ampere receptacle outlet readily accessible from grade and NOT more than _____ above grade level shall be installed at the front and back of the dwelling.

6 1/2 feet

In pull boxes or junction boxes having any dimension over _____, all conductors shall be cabled or racked up in an approved manner.

6 feet

in pull boxes or Junction boxes having any dimension over _____ , all conductors shall be cabled or racking up in an approved manner.

6 feet

Household-type appliances with surface heating elements having a MAXIMUM demand of more than _____ shall have its power supply subdivided into two (2) or more circuits.

60 amperes

What is the MAXIMUM overcurrent protection allowed for the protection of resistance-type electric space heating equipment?

60 amperes

household-type appliances with surface heating elements have a maximum demand of more than _______ shall have its power supply subdivided into two or more circuits.

60 amperes

when exceptions are not to be taken into consideration, what are the smallest size copper conductors permitted for use as overhead service-drop conductors?

8 awg

A ground rod is required to be driven a MINIMUM depth of _____ into the earth.

8 feet

Direct-buried conductors emerging from grade shall be protected by raceways or covers up to at LEAST _____ above finished grade.

8 feet

In general, overhead (aerial) communications wires and cables shall have a vertical clearance of NOT less than _____ from all points above roofs which they pass.

8 feet

When a conductor has a computed ampacity of 75 amperes, the MAXIMUM standard ampere rating of the overcurrent protection device the NEC permits to protect this circuit is rated _____ if this is not a motor circuit or part of a branch circuit supplying multiple receptacles.

80 amperes

when a conductor has a computed ampacity of 75 amperes, the maximum standard ampere rating of the overcurrent protection device the nec permits to protect this circuit is rated ___________ if this is not a motor circuit or part of a branch circuit supplying multiple receptacles

80 amperes

Given: You are to install a back-up generator with a rating of 18 kW, 120/240-volts, single-phase, at a farm house. Where the design and operation of the generator does not prevent overloading, the ampacity of the conductors from the generator terminals to the first overcurrent protective device must be at LEAST _____.

86 amperes

In industrial establishments, where sizes 1/0 AWG through 4/0 AWG single conductor cables are installed in ladder type cable tray, the MAXIMUM allowable rung spacing for the cable tray shall be _____ .

9 inches

When determining the required ampacity of the branch-circuit conductors to supply a 3-phase, continuous-duty ac motor, current values given on _____ shall be used.

Table 430.250 of the NEC

A listed _____ shall be installed in or on all emergency systems switchboards and panelboards.

surge protective device (SPD)

The connection between the grounded circuit conductor and the supply-side bonding jumper, or the equipment grounding conductor, or both, at a separately derived system is defined as the _____ in the NEC.

system bonding jumper

The lightning protection system ground terminals shall be bonded to _____.

the building or structure grounding electrode system

A premises wiring system supplied by a grounded ac electrical service, shall have a grounding electrode conductor connected to _____ .

the grounded service conductor

Where fuses are used for motor overload protection, if the supply system is a 3-wire, 3-phase, ac with one conductor grounded, the NEC requires a MINIMUM of _____ fuse(s).

three

In guest rooms of hotels, motels, and sleeping rooms of dorms a MINIMUM of _____ general purpose receptacles installed in the room is/are required to be readily accessible.

two

Determine the MINIMUM trade size electrical metallic tubing (EMT) required to enclose eight (8) size 6 AWG copper conductors with THHW insulation when installed in a 50 ft. conduit run.

1 1/4 in.

When installing Type NM cable through bored holes in wooden studs, the holes shall be bored so that the edge of the hole is NOT less than _____ from the nearest edge of the wood member, unless the cable is protected by a steel plate.

1 1/4 in.

Determine the MINIMUM number of 20-ampere, 120-volt general lighting branch circuits required for a 12 unit apartment building that is 12,000 sq. ft. in size. The apartment building is not designed for permanent residents and does not contain cooking facilities.

10

What is the MAXIMUM allowable voltage between branch-circuit conductors supplying luminaires in a residence or guest rooms of hotels and motels?

120 volts

Wiring located above heated ceilings, where installed less than two (2) inches above the heated ceiling, shall be considered as operating at an ambient temperature of _____ .

122 deg. F

Branch-circuit conductors supplying a fixed storage-type electric water heater with a capacity of 120 gallons or less, shall have an ampacity of NOT less than _____ of the full-load current of the water heater.

125 percent

Luminaires mounted in walls of permanently installed swimming pools, shall be installed with the top of the luminaire lens NOT less than _____ below the normal water level of the pool, unless the luminaire is listed and identified for use at lesser depths.

18 inches

Where compressed natural gas vehicles are repaired in a major repair garage, the area within _____ of the ceiling shall be considered unclassified where adequate ventilation is provided.

18 inches

where conduits enter a floor-standing switchboard or panel board at the bottom, the conduits, including their end fittings, shall not rise more than _________ above the bottom of the enclosure.

3 inches

where am AC service is supplied with four parallel sets of size 500 kcmil aluminum conductors, what is the minimum six copper grounding electrode conductor required, when connected to a metal underground water line used as the grounding electrode system?

3/0 AWG

Shore power for boats shall be provided by single receptacles rated NOT less than ______ .

30 amperes

The MAXIMUM ampacity of an individual branch circuit in a flat conductor cable (FCC) assembly shall be _____ .

30 amperes

Where exceptions are not applicable, when a feeder supplies a continuous load of 240 amperes, the overcurrent protection device protecting this circuit shall have a rating of at LEAST _____.

300 amperes

What is the MAXIMUM distance allowed between supports when installing nonmetallic sheathed cable (NM)?

4 1/2 feet

When terminating conductor sizes 14 AWG through 1 AWG on circuit breakers, the conductors shall be considered to have a temperature rating of ______, unless the circuit breakers are listed and marked otherwise.

60 deg. C

Conduit nipples not over 24 inches in length may be filled to a MAXIMUM of _____ of their cross-sectional area.

60 percent

in regards to electric space heating equipment, heating cables shall be furnished complete with factory-assembled nonheating leads at least ________ in length.

7

A 20-ampere, 120-volt load is located 150 ft. from a panelboard and is supplied with size 10 AWG copper branch-circuit conductors with THWN-2 insulation. What is the approximate voltage drop on the conductors? (K = 12.9)

7.5 volts

Where an 80-ampere, 240-volt, single-phase load is located 200 feet from a panelboard and is supplied with size 3 AWG copper conductors with THWN insulation, what is the approximate voltage-drop on the circuit?(K = 12.9)

7.84 volts

Generally, at the location of all ground- and pole-mounted photovoltaic arrays and as close as practicable to roof-mounted PV arrays a/an _____ is required to be installed.I. auxiliary grounding electrode systemII. single-phase, 125-volt, 15- or 20-ampere, GFCI protected receptacle

I only

Class _____ locations are those that are hazardous because of the presence of easily ignitible fibers or where materials producing combustible flyings are handled, but in which such fibers/flyings are not likely to be in suspension in the air in quantities sufficient to produce ignitible mixtures.

III

the continuity of the grounding system for portable electrical carnival equipment shall be verified

each time the equipment is connected

A concrete-encased grounding electrode shall consist of at LEAST _____ in one continuous 20 foot length. I. size 4 AWG bare copper conductor II. 1/2 in. diameter steel reinforcing rod

either I or II

Three-way and four-way switches shall be wired so that all switching is done

only in the ungrounded circuit conducror

On a 4-wire, delta-connected electrical system, the conductor having the higher voltage to ground, (high-leg), shall be identified as _____ in color, if the grounded conductor is also present to supply lighting or similar loads.

orange

Receptacles incorporating an isolated grounding conductor connection intended for the reduction of electrical noise, shall be identified by a/an _____ located on the face of the receptacle.

orange triangle

Where the motor controller also serves as a disconnecting means, it shall open all _____ conductors to the motor.

ungrounded

For solar photovoltaic systems, locating the system grounding connection point as close as practicable to the photovoltaic source better protects the system from _____.

voltage surges due to lightning


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