Electrical Systems Ch. 19

The system ground must be connected to an underground metal water(not gas) pipe in direct contact with the earth for no less than _____ feet.

10

The common connected Load (VA) for a dishwasher is ________ (VA), and should have overcurrent protection of ____ amps (A).

1000, 20

The __________ system is the most basic system voltage used.

120 V AC, 1Φ-2W

The ____________ is the most common residential electrical service in use today.

120/240 V AC, 1 Φ-3W

When determining a circuit rating, most loads deemed continuous must have a circuit rating calculated at ____% of the circuits connected load.

125

Heat generated at the equipment terminals can damage the conductors if it is not properly dissipated. Unless equipment terminals are marked otherwise, circuit conductors are to be sized according to ______°F for equipment rated 100A and less, and equipment rated over 100A must be sized to ______°F.

140, 167

A minimum of ___ types of conductors is required to deliver alternating current in a building electrical system.

2

The system ground must be connected to an electrode made of a grounding ring of bare copper wire no smaller than No. 2 AWG that encircles the building at a depth no less than ____ feet below grade.

2.5

The system ground must be connected to an electrode made of at least ___ feet of electrically conductive steel reinforcing bars (No. 4 AWG or greater) or bare copper wire no smaller than No. 2 AWG that is encased in at least ____ inches of concrete that is part of a foundation or footing indirect contact with the earth.

20, 2

The __________ is an older electrical service found in small commercial buildings and high-rise buildings where three-phase motors and equipment such as large air conditioners are used.

208 Y/120 V AC, 3Φ-4W

Each hall over ___ ft^2 in floor space should have at least one receptacle.

25

Based on a power factor of 1.0, a connected load of 3,000 VA on a 120 volt circuit would carry ____ amps.

25.00

A continuous load is a load that operates for ___ hour or more at any time.

3

The NEC is revised every ___ years

3

Utilizing the standard connected loads, voltages, and requirements for appliances and equipment in laundry spaces, a Clothes dryer (electric household) should have ____ No. 10 Conductors Excluding Grounding.

3

Convenience receptacles in bathrooms are normally mounted approximately ___ inches AFF.

44

Switches are normally mounted approximately _____ inches AFF.

48

In most commercial and industrial installations, several disconnects may be used. Commonly, a maximum of ____ service disconnects per service is allowed.

6

Convenience receptacles in living rooms, bedrooms, dining areas, and other habitable spaces should be placed so that no point along the floor line in any usable wall space is more than ___ feet from an outlet in that space, and any wall ____ feet or more in length must have a convenience receptacle.

6, 2

To prevent stretching of conductors as they are pulled through the conduit or tube, bends must be made no smaller than the minimum radius specified by code, about ___ to ___ times the conduit diameter.

6, 8

A wall-switched or timer-operated, built-in ventilating fan capable of a minimum of ___ to ___ air changes per hour per water closet should be provided where no natural ventilation through windows is included

8, 10

This is the type of branch circuit that supplies energy to one or more outlets to which appliances are to be connected. They supply fixed electric equipment such as refrigerators, washers, and other large appliances and electrical devices.

Appliance branch

A(n) _____________________ product meets minimum safety standards as determined by extensive testing by an independent testing company or organization.

Approved

NM cable must have 194°F conductor insulation rating, which is designated by a "___" on the cable sheath.

B

Using the commonly used, but not mandatory color sequence of conductors serving single-phase circuiting, a four wire system with a white ground will have what colors as the ungrounded conductor?

Blue, red, black

A(n) _________________ is that portion of a building wiring system that extends beyond the final overcurrent protection device that is protecting a circuit.

Branch circuit

Medium-and large-gauge stranded aluminum cable (above No. 8 AWG) is safely used on circuits as long as the terminals or connectors on the circuit are rated ___________ and an antioxidant paste is used on properly tightened connections.

CU-AL

The _______________ on a branch circuit is the sum of all loads connected in a circuit. It is found by totaling the connected volt-amp (VA) load at each outlet connected to the circuit.

Connected load

An emergency system of feeders and branch circuits intended to provide power to task illumination, special power circuits, and selected receptacles serving areas and functions related to patient care. It must automatically connect to an alternate power source such as a generator when the normal power sources is interrupted.

Critical branch circuit

__________________ refers to a grounding conductor or grounding path that connects the noncurrent-carrying metal components of equipment.

Equipment ground

A NMA or TEL mark on a product indicates that the device or piece of equipment has met minimum safety standards as determined by extensive testing.

False, a UL or ETL

The branch circuit rating is determined by the rating of the individual circuits.

False, it is determined by the rating of the overcurrent protection device (fuse or circuit breaker) used to protect the wiring in the circuit from excessive current flow

NM and NMC cable is permitted in underground installations, and in buildings that are more than three stories above grade or in commercial garages.

False, it is not permitted for underground use in buildings that are more than three stories above grade or in commercial garages, motion picture studios, theaters, places of assembly, elevator hoist ways, and other corrosive or hazardous locations

Grounded and neutral conductors should not be wired so a circuit breaker, fuse, or switch does not interrupt them.

False, should be wired

Switches do not have to be selected for the load they control, as long as the wires will fit in the screw slots.

False, switches must be selected to match the load they control

Wall switches should be located so as to be readily accessible while standing in the tub or shower stall.

False, the should not be readily accessible from the tub or shower. It could cause electrical shock. Generally more than 3'.

Feeder conductors need to be sized to carry the total connected load served by the feeder.

False, they do not need to be sized for the total load because not all loads should be on at the same time

Most municipalities do not require that a permit be issued before any electrical installations may be made on a project.

False, they require one to be issued

Bonding jumpers are not required in instances when flexible conduit is used.

False. they are definitely required

A branch circuit supplies two or more outlets for lighting and appliances. This type of circuit may be referred to as a lighting circuit; this is a carryover from the days when electricity was first used in buildings and its predominant purpose was lighting.

General purpose

A(n) ____________allows outdated electrical installations to remain in use if they are not regarded as hazardous.

Grandfather clause

The equipment-grounding conductor is a bare conductor or a __________-colored, insulated conductor that connects (bonds) the outlet boxes, metallic raceways, other enclosures and frames on motors, appliances, and other electrical equipment.

Green

A _________________ is required to complete a single phase circuit by connecting the ungrounded (hot) conductor to ground

Grounded conductor

This type of branch circuit serves only one receptacle or piece of equipment such as for a range, clothes dryer, large copy machine, or other piece of machinery.

Individual branch

An emergency system of feeders and branch circuits that provides adequate power to patients and personnel.

Life safety branch circuit

______________ is the highest voltage to which a wiring device can be exposed.

Maximum voltage

A branch circuit consisting of two or more grounded (hot) conductors having a voltage between them and a common neutral (grounded) conductor that is shared between the ungrounded conductors such as in a 120/240V three-wire circuit. In this circuit, all conductors must originate from the same panelboard.

Multiwire branch circuits

What is the leading trade association in the United States representing the interests of electrical manufacturers?

NEMA

NEC stands for what?

National Electrical Code

On delta-connected systems, Phase Y has a higher voltage to ground than the other legs. Code requires that this phase be marked by the color _____________.

Orange

Power is delivered by the utility company to the user as

Supply voltages

________________ voltage is target voltage entering the service panel.

System

_______________ grounding is that part of a building electrical system that provides protection against electrical shock, lightning, and fires.

System ground

Although there are no size limitations for an individual circuit rating, appliances and equipment rated at above 25 Amps must be placed on a separate individual circuit because of the 50% maximum single load limitation in general purpose circuiting.

True

Amperage determines conductor size, and higher voltages mean lower amperage, which allows use of smaller conductors.

True

An outdated installation must be changed only if it is part of a renovation project.

True

Constant exposure to high temperatures increases the deterioration rate of insulation, so a conductor exposed to higher temperatures will have a lower ampacity than on that is operating in the normal temperature range.

True

If properly bonded, a metal raceway (conduit) or armored cable system can serve as a means of equipment grounding so an equipment-grounding conductor is not actually needed.

True

In service equipment panelboards, the neutral and equipment grounding conductors are bonded (connected) together. In subpanelboards, the neutral is isolated from ground; that is, there are separate neutral/grounded grounding buses.

True

Junction boxes must be mounted so that the blank cover plate is visible and readily accessible.

True

Most municipalities have ordinances (local laws) that require that any person who wishes to engage in the business of installing electrical systems must be licensed (usually by the state or province).

True

On a two-wire branch circuit, the grounded conductor carries current equal to the load.

True

One or more lighting outlets should be located at or near all exterior entrances.

True

The grounding conductor is a continuous conductor that connects the ground to the neutral bus bar and the grounding conductor bus bar in the service equipment/main panelboard.

True

The grounding conductor is not normally a current-carrying conductor, but is energized only on a temporary, emergency basis when there is a fault between an ungrounded (hot) conductor and any metal associated to the electrical equipment.

True

The voltage rating of a fuse or circuit breaker must be equal to or greater than the voltage of the circuit in which the fuse is applied.

True

You must have conduit that is buried in concrete inspected before concrete is placed over it.

True

List the two(2) testing organizations that can test and approve equipment safe.

Underwrites Laboratory, Inc. (UL) ETL Testing Laboratories

The _____ is the initial current carrying conductor in an AC system.

Ungrounded

______________ accounts for anticipated voltage drops on branch circuit conductors. A voltage drop occurs as current flows from the service equipment through the branch circuit conductors to the outlet.

Utilization voltage

A ________________ is a set of conductors that carry a comparatively large amount of power from the service equipment to a second panelboard, called a subpanelboard.

feeder

A(n) ____________________ performs the function of a grounded conductor for at least two ungrounded (hot) conductors that have sources from different voltage phases, such as on a multiwire branch circuit, multiwire feeder, and the electrical service.

neutral conductor