ET Exam 4

What is the primary disadvantage of an automatic instantaneous demand control system for electric power? (a) The system cannot readily adapt to varying load patterns. (b) The system cannot be controlled by humans once it is brought online. (c) The system cannot be operated unless the facility it serves has at least 20% sheddable loads of at least 150 kVA. (d) The system cannot be operated as part of a larger building energy control system.

(a) The system cannot readily adapt to varying load patterns.

The advantage of using a contactor rather than a switch is that: (a) a contactor can be remote controlled (b) a contactor is less likely to fail (c) a contactor can handle higher voltages (d) a contactor can handle more current

(a) a contactor can be remote controlled

Which of the following would be a good location for an electrical closet? (a) a location where conduits can enter and leave the location vertically and horizontally (b) on an outside wall (c) adjacent to a stairwell (d) adjacent to a column

(a) a location where conduits can enter and leave the location vertically and horizontally

Use of AC cable is typically confined to: (a) dry locations (b) underground conduits (c) overhead transmission lines (d) small buildings

(a) dry locations

A "step-down" transformer: (a) has a greater number of turns in its primary coil than its secondary coil (b) has a greater number of turns in its secondary coil than its primary coil (c) changes electric current from alternating to direct current (d) changes electric current from direct to alternating current

(a) has a greater number of turns in its primary coil than its secondary coil

Which of the following is not a typical use of dc power? (a) high-voltage transmission lines (b) building controls (c) telephones (d) battery powered devices

(a) high-voltage transmission lines

In a typical building electrical power system wiring closet, dry-type transformers are typically placed between: (a) plug-in busways and 120-V panelboards (b) a plug-in switch and a 277-V panelboard (c) the building switchboard and a centralized motor control (d) the service feeder and a plug-in busway

(a) plug-in busways and 120-V panelboards

To accommodate a home office worker, master bedrooms should be provided with a minimum of: (a) six duplex 15-A or 20-A receptacles connected to at least two different circuits (b) five duplex 15-A or 20-A receptacles connected to the same circuit (c) three telephone jacks (d) a separately insulated ground wire, connected only at the service point, that connects to three or more receptacles

(a) six duplex 15-A or 20-A receptacles connected to at least two different circuits

Raceways have now become a major architectural consideration that must be addressed early in the design process because: (a) the proliferation of computers and networking equipment require the distribution channels to be much wider than before (b) building codes have become stricter (c) extensive knowledge of electrical equipment is now required to obtain an architectural registration (d) the excessive reliance on electricity to power an increasing number of devices presents a greater fire hazard

(a) the proliferation of computers and networking equipment require the distribution channels to be much wider than before

Oil-insulated transformers can be expensive to install indoors because: (a) they must be placed in a fire-resistant vault (b) the price of oil is rising (c) of their high purchase cost (d) most contractors do not understand how to install them

(a) they must be placed in a fire-resistant vault

Electrical energy cost is directly related to energy consumption, except in the case of: (a) utility demand charges (b) low-wattage bulbs (c) industrial applications (d) three-phase contactors

(a) utility demand charges

The name given to the force driving electron flow between positive and negative terminals is: (a) voltage (b) wattage (c) ohms (d) current

(a) voltage

Which building electrical sub-system includes panelboards and circuit breakers? (a) wiring and raceways (b) power-handling equipment (c) utilization equipment (d) limiters

(a) wiring and raceways

Energy is the technical term for the more common expression: (a) "power" (b) "work" (c) "electricity" (d) "voltage"

(b) "work"

Lighting tracks are generally rated at: (a) 10 A (b) 20 A (c) 40 A (d) 100 A

(b) 20 A

A power utility will most likely find overhead transmission economically feasible for voltages greater than: (a) 1000 V (b) 5000 V (c) 200,000 V (d) 500,000 V

(b) 5000 V

If a building's emergency power supply consists of batteries, the batteries must have a full-load capacity of: (a) 60 minutes (b) 90 minutes (c) 120 minutes (d) 240 minutes

(b) 90 minutes

A 120/208-V single-phase, three-wire system would be used primarily to serve: (a) a load that does not exceed 20 A (b) a single-family residence or small commercial building (c) a load that involves many three-phase motors (d) resistive loads

(b) a single-family residence or small commercial building

A "drawout" switchboard is: (a) a type of switchboard that has a breaker that trips when a current of more than 3000 A is drawn (b) a type of switchboard that has circuit breakers mounted in a movable drawer (c) a type of switchboard that can be easily removed from its mounting and transported (d) a switchboard that has been recovered from a demolished building and repaired to meet the needs of its current building

(b) a type of switchboard that has circuit breakers mounted in a movable drawer

In a series circuit, voltages and resistances are: (a) subtracted (b) added (c) divided (d) multiplied

(b) added

To avoid the risk of electric shock, it is recommended that appliance housings be grounded to a: (a) junction box (b) cold-water pipe (c) raceway (d) another appliance

(b) cold-water pipe

Devices that carry the description "energy management" have a primary function of controlling: (a) demand (b) energy use (c) resistance (d) voltage

(b) energy use

Which type of interior wiring system is typically only used in industrial applications? (a) exposed insulated cables (b) insulated cables in open raceways (c) insulated conductors in closed raceways (d) combined conductor and enclosure

(b) insulated cables in open raceways

A busway or busduct is ideally used when ______. (a) outdoor temperatures drop below 0oC (32oF) (b) it is necessary to carry large amounts of current (c) it is necessary to carry high voltages (d) direct connection to service feeders must be achieved indoors

(b) it is necessary to carry large amounts of current

The most popular form of exterior transformer installation for individual buildings is: (a) mounted on a pole (b) mounted on a concrete pad (c) underground (d) incorporated into the building façade

(b) mounted on a concrete pad

The "ohm" is a unit of measurement for: (a) voltage (b) resistance (c) current (d) frequency

(b) resistance

A "ratchet" clause in a utility billing plan is disadvantageous for which type of user? (a) users with consistent energy demand (b) users with a low yearly load factor (c) users with a high yearly load factor (d) infrequent power consumers

(b) users with a low yearly load factor

Which of the following is not a valid electrical switch class? (a) 250 V (b) 600 V (c) 1.5 kV (d) 5 kV

(c) 1.5 kV

Which of the following volt-amperage values would be logical for a 15-A residential circuit operating at 25% expansion? (a) 1440 V-A (b) 1920 V-A (c) 1150 V-A (d) 1520 V-A

(c) 1150 V-A

For the purpose of predicting overall building electrical load, continuous loads should be calculated at ___ of their actual value. (a) 50% (b) 80% (c) 125% (d) 175%

(c) 125%

Which of the following would be a typical dimension of a single-phase uninterruptible power supply (UPS) unit? (a) 6 in. x 6 in. x 12 in. (152 x 152 x 305 mm) (b) 18 in. x 10 in. x 24 in. (457 x 254 x 610 mm) (c) 36 in. x 12 in. x 36 in. (915 x 305 x 915 mm) (d) 60 in. x 24 in. x 36 in. (1525 x 610 x 915 mm)

(c) 36 in. x 12 in. x 36 in. (915 x 305 x 915 mm)

To protect against all types of weather conditions, one should specify an equipment enclosure of type: (a) 3R (b) 3S (c) 4 (d) 4R

(c) 4

In commercial spaces, an electrical closet might be preferable to a stand-alone panelboard for a building of ___ or more stories. (a) 2 (b) 4 (c) 6 (d) 10

(c) 6

Which of the following is not a maxim for the safe grounding of a secondary wiring system? (a) The neutral wire in a secondary system must never be interrupted by switches or other devices. (b) The neutral wire must be connected to the ground only at one point— the service entrance. (c) The neutral wire must be color-coded yellow on any insulation color other than blue, along at least half the conductor length. (d) The neutral must be color-coded white, natural gray, or by three continuous white stripes on any insulation color other than green, along the entire conductor length.

(c) The neutral wire must be color-coded yellow on any insulation color other than blue, along at least half the conductor length.

Which of the following transmission line methods is the most expensive? (a) overhead (b) direct burial (c) Type I burial (d) Type II burial

(c) Type I burial

A conductor's current-carrying capacity is referred to as its: (a) American Wire Gauge (AWG) (b) wattage (c) ampacity (d) capacitation

(c) ampacity

Which of the following occupancy types exhibits the highest air-conditioning load? (a) art gallery (b) cafeteria (c) auditorium (d) school classroom

(c) auditorium

In a transformer, ___ remains constant. (a) voltage (b) current (c) power capacity (d) resistance

(c) power capacity

The unit of electric current is: (a) the volt (b) the watt (c) the ampere (d) the hertz

(c) the ampere

The use of nonflammable liquid coolants has largely been discontinued in transformers because: (a) this was the most expensive and least efficient way to cool the devices (b) of their tendency to explode (c) the coolants contain PCBs, which are banned in new installations (d) they presented a higher than normal risk of electrocution

(c) the coolants contain PCBs, which are banned in new installations

The current rating of an electrical service item is determined by: (a) the wattage of all devices that are to be connected to the item (b) the voltage rating of all devices that are to be connected to the item (c) the maximum temperature at which its components can operate at full load (d) the maximum operating voltage at which its components can operate at full load

(c) the maximum temperature at which its components can operate at full load

The overall load factor is: (a) the maximum load generated by a residential household (b) the average load generated by all electrical customers in a given area (c) the ratio between the average and maximum power demands of a building (d) the maximum dc load plus the maximum ac load

(c) the ratio between the average and maximum power demands of a building

In a parallel circuit, current at each load depends upon: (a) the current in each successive load (b) the resistance of all loads (c) the resistance of each load (d) the current in a series circuit

(c) the resistance of each load

A load center pad-mounted unit substation would typically have a primary voltage range of: (a) 120-600 V (b) 2.5-34.5 kV (c) 2.5-67 kV (d) 2.5-15 kV

(d) 2.5-15 kV

The best distribution system for a large, multistory building that principally uses fluorescent or HID lamps is: (a) 120 V, single-phase, 2-wire (b) 120/240 V, single-phase, 3-wire (c) 120/208 V, single-phase, 3-wire (d) 277/480 V, 3-phase, 4-wire

(d) 277/480 V, 3-phase, 4-wire

Direct current can be defined as a condition where: (a) the flow of current is periodically varying in time and direction (b) the current travels directly from the power generation source to an outlet (c) an electrically powered generating source generates the current (d) a flow of current takes place at a constant rate in the same direction around a circuit

(d) a flow of current takes place at a constant rate in the same direction around a circuit

Almost all indoor unit substations use ____ transformers. (a) oil-filled (b) nonflammable fluid-filled (c) liquid-insulated (d) dry-type

(d) dry-type

In the design procedure for wiring a building, one would compute panel loads before: (a) data-processing and signal apparatuses are located (b) lighting is designed (c) the electrical rating of all building equipment is determined (d) feeder and protective equipment ratings are computed

(d) feeder and protective equipment ratings are computed

A single conductor of No. 8 AWG standard (a) is heavier than a No. 7 conductor (b) is referred to as a "cable" (c) is the largest AWG designation (d) is referred to as a "wire"

(d) is referred to as a "wire"

The advantage of using a cablebus over a busduct is that: (a) it is less bulky (b) it can be run for longer distances (c) it generates less heat (d) it has a higher amperes-per-dollar first-cost

(d) it has a higher amperes-per-dollar first-cost

In a two-level underfloor duct system, ducts are run near the center of a bay in a depressed-slab system: (a) to avoid running into walls (b) so as not to become a trip hazard (c) to avoid intersection with water pipes (d) to avoid the steel in beams or joists near columns

(d) to avoid the steel in beams or joists near columns