2nd quarter exam plus add'l questions
Under the optional method of calculation for a single-family dwelling, all "other load" beyond the initial 10 kVA is to be assessed at ___ percent.
40
A 10 KVA transformer has a 120/240-volt secondary. Each of the two secondary windings can carry ___ amps without being overloaded.
41.67
The maximum number of 15-amp receptacles permitted on a freestanding office partition is ___
13
A 50 hp 230-volt, 3-phase squirrel cage motor has a full-load current of ___ amps.
130
An attachment plug and receptacle may be permitted to serve as a motor controller if the motor is portable and has a maximum rating of ___ hp.
1/ 3
Where an electric power production source is connected to the supply side of the service disconnecting means, the sum of the ratings of all overcurrent devices connected to power production sources shall not exceed this percentage of the rating of the service.
100
Branch-circuit conductors that supply a single motor used in a continuous duty application shall have an ampacity of not less than ___ of the motor's full-load current rating as determined by 430.6(A)(1).
125%
Determine the minimum size overload protection required for a 480-volt, 3-phase, 15 hp, continuous duty motor given the following information.* Design B * temperature rise - 40ºC* service factor - 1.12 * actual nameplate rating - 18
20.7 amps
Conductors that supply one or more arc welders shall be protected by an overcurrent device rated or set at not more than ___% of the conductor ampacity.
200
The minimum feeder allowance for show window lighting expressed in volt-amps per linear foot shall be ___ VA.
200
Equipment grounding conductors for PV source and PV output circuits shall be sized in accordance with ___.
250.122
A disconnecting means shall be provided for all ungrounded conductors derived from a stationary battery system with a voltage over _____ volts dc
60
What is the demand factor for five household clothes dryers?
85%
A 1Ø transformer has a power rating of 37.5 KVA with a 480-volt primary and a 120/240-volt secondary. The transformer is delivering power to a 22 KVA load at 240 volts. The transformer is supplying ___ amps of current to the load.
92
A ___ system is used for surveillance and/or recorded documentation.
CCTV
Cat ___ UTP cables are used for LANs. I.6 II.3 III.5E
I or III only
For a fire alarm system, the FACP ___ .I. requires a 120-Vac dedicated circuit as its power supply II. breaker must be marked red in color III. breaker must be labeled Fire Alarm Control Unit
I, II & III
The installation of a fire alarm system requires a riser cable to be run between floors. Which of the following cable types is acceptable? I.CMR II.CMP III.FPLR IV.FPLP
I, II, III, or IV
An ___ has no direct electrical connection between the primary and secondary windings.I. autotransformer II. isolation transformer
II only
An isolation transformer is routinely used where "clean power" is required to operate delicate electronic equipment such as computers.
True
Digital telephone networks inside a building utilize ___ to maintain connection between each telephone and the head-end.
UTP cable
A 120-volt receptacle located at ___ feet from the inside wall of a swimming pool must be GFCI protected.
all of these
A typical standby system ATS ___.
all of these
After repairs have been made to an existing fire alarm system, you should put the system back on line ___ notifications are made.
before
A(n) ___ fire alarm system groups notification devices into zones.
conventional
An optical fiber cable transmits ___.
photons
The purpose of turning on exhaust fans when fire-control equipment is activated is to ___.
remove deadly gases from the area
A dual-action fire alarm pull station ___.
requires two hand actions to operate the station
From the head-end of a CCTV system, ___.
separate cables are installed to each camera
Where interconnected electric power production sources supply, equipment containing _____ devices in circuits supplying power to a busbar or conductor supplied from multiple sources shall be marked to indicate the presence of all sources.
overcurrent
When 10/2 AWG with ground type SO cord is used to supply border lights in a theater, the cable has an ampacity of ___ amps.
30
For a touring circus, continuity of the equipment grounding conductor system shall be verified ___.
each time that portable electrical equipment is connected
Lugs for transformers can be made of ___.
either copper or aluminum
Transformers operate on the principle of ___.
electromagnetic induction
Generally, ___ cable has a higher bandwidth and can transmit larger amounts of data.
fiber optic
All electric equipment, including power supply cords, used with storable pools shall be protected by ___.
ground-fault circuit interrupters
Which of these grounding configurations is not permitted for PV systems?
high resistancel-grounded
When installing a fire alarm system, survivability cable is typically used in a ___.
hospital
Storage batteries, other than lead-acid batteries, shall be _____.
listed
Temperature rise in a transformer is the ___ without damage occurring to the windings.
maximum temperature above the surrounding air temperature that can occur in the windings
Automatic transfer switches (ATS) for emergency systems shall be electrically operated and ___ held.
mechanically
The load to be connected to a new transformer is 88.2 KVA. The specifications require that the transformer be sized at 120% of the connected load to allow for future expansion. The minimum calculated size of the transformer is ___ kVA.
none of these
The 3 volt-ampere per square foot unit load for dwelling unit general lighting includes all 15- and 20-ampere general-use receptacles. The floor area shall ___ open porches, garages, or unused or unfinished spaces not adaptable for future use.
not include
When service-entrance conductors exceed 1100 kcmil for copper, the required grounded conductor must be sized not less than ___ percent of the area of the largest phase conductor.
12.5
Conductors supplying a fire pump motor(s), pressure maintenance pumps, and associated fire pump accessory equipment shall have a rating not less than ___% of the sum of the fire pump motor(s) and pressure maintenance motor(s) full-load current(s), and ___% of the associated fire pump accessory equipment.
125 100
The power supply to the mobile home shall be a feeder assembly consisting of not more than one listed ___-ampere mobile power-supply cord with an integrally molded or securely attached plug cap or a permanently installed feeder.
50
The turns ratio for a transformer with a primary rated voltage of 120 and a secondary rated voltage of 24 is ___:___.
5:1
No receptacle shall ever be permitted to be installed within ___ feet of the inside walls of a pool.
6
___ feet is the maximum distance that a disconnect can be located from the operator's station for a carnival ride?
6
When calculating the service-entrance conductors for a farm service, the second-largest load of the total load, shall be computed at ___%.
75
A transformer with a nameplate rating of 240/480-V pri — 120/240-V sec can be connected to a 2-pole breaker in a ___ panelboard and deliver nameplate-rated voltage to a load.I. 120/208-V 3Ø, 4-WII. 120/240-V 3Ø, 4-WIII. 277/480-V 3Ø, 4-W
II or III only
The installation of a fire alarm system requires a plenum cable to be run above the lay-in ceilings. Which of the following cable types is acceptable? I.CMR II.CMP III.FPLR IV.FPLP
II or IV only
Audible and visual signal devices on emergency system transfer equipment shall be provided where practicable for ___.
all of these
As part of a fire alarm system, a horn/strobe provides ___ to alert building occupants that a fire alarm has been activated. a. light b. sound c. both a and b
both a and b
To avoid panic in occupancies such as hospitals when a fire alarm system is activated, ___ to alert trained personnel.
chimes or other special signaling systems are utilized
Because it provides less signal loss, quad-shield coaxial cable is used for ___ TV signals.
digital
Residential audio systems generally utilize ___-ohm speakers.
8
What is the demand load for eighty receptacles located in a 15,000-square-foot office building?
15,000
Nine-foot lengths of 1/0 AWG copper THHN/THWN conductors are installed from a 120/240-V, 1-ph, 3-wire panel to the secondary terminals on a 50 KVA transformer. The maximum rating of the main breaker in the panel is ___ amps. The breaker terminals are rated at 75ºC.
150
When fully loaded, a 480-volt pri/240-volt sec 37.5 KVA 1Ø, 3-wire transformer can deliver ___ amps to a 240-volt load.
156.25
Determine the maximum current setting permitted for overload protection for a motor that has a thermal protector integral with the motor, given the following information.* 7 1/ 2 hp - wound rotor type * two-phase, 4 wire, AC * 230 volts
29.6 amps
Disregarding exceptions, what is the minimum number of overload units required by the NEC ® to protect a 3-phase motor?
3
Where fuses are used for motor overload protection and the supply system is a 3-wire, 3-phase AC with one conductor grounded, the NEC ® requires a minimum of how many fuses?
3
A code letter D is marked on a motor nameplate. What is its locked-rotor kVA per horsepower
4.0 - 4.49
A transformer has a nameplate rating of 480-volt primary - 120/240-volt secondary. If instead of rated voltage the applied primary voltage is 440 volts, a 5 KVA transformer could deliver a maximum output of ___ kVA without overloading.
4.58
A 14 AWG THHN copper conductor is used between a motor starter and a remote start/stop station. What is the maximum size circuit breaker permitted for the motor short-circuit ground-fault protection that will also protect the 14 AWG conductor?
45 amp
A transformer has a primary rated at 240 volts and a secondary rated at 120 volts. A 120-volt load connected to the secondary of the transformer is pulling 10 amps. The transformer is supplied from a 2-pole breaker in a 120/240-volt 3Ø, 4-wire panelboard. ___ amps is flowing in the circuit conductors that connect to the primary.
5
Luminaires located over a spa or within 5 feet from the inside walls of the spa shall be permitted to be not less than ___ feet above the maximum water level where protected by a GFCI.
7 1/2
The load to be connected to a new transformer is 62.5 KVA. The specifications require that the transformer be sized at 115% of the connected load to allow for future expansion. The minimum calculated size of the transformer is ___ kVA.
71.875
The demand factor for six residential clothes dryers in a multifamily dwelling unit is ___.
75%
Where fixed multioutlet assemblies are employed, each ___ feet or fraction thereof of each separate and continuous length shall be considered as one outlet of not less than 180 volt-amperes where the connected appliances are unlikely to be used simultaneously.
8
A transformer has a primary rated voltage of 120 and a secondary rated voltage of 24. If you measure an output on the secondary of 16 volts, ___ volts has been applied to the primary.
80
Photovoltaic systems operating at _____ volts dc or greater between any two conductors shall be protected by a listed PV arc-fault circuit interrupter or other system components listed to provide equivalent protection.
80
When installing coaxial cable, the tension applied when pulling can not exceed ___ pounds.
90
A 7.5 KVA, 240-Volt, 1Ø transformer loaded at 105% is delivering ___ amps to the connected loads.
32.81
A 480 primary to 120/240-volt secondary single-phase transformer is actually supplied by 496 volts. If no tap changes are made, what line-to-neutral output voltage will be available?
124
Individual appliances that are continuously loaded shall have the branch-circuit rating sized no less than ___ percent of the appliance's marked ampere rating.
125
Overcurrent protection for feeders and branch circuits supplying electric vehicle supply equipment shall have a rating of not less than ___% of the maximum load of the electric vehicle supply equipment.
125
A 120/240-volt, 1Ø, 3-wire panelboard is to be fed from a transformer. The minimum calculated (NOT STD) size of the transformer is ___ kVA where the following loads are connected:Circuit 3-5: 12.1 amp 240-volt swimming pool motorCircuit 2-4: 14 kW 240-volt heaterCircuit 6-8: 5.2 amp 240-volt motor
18.152
Communications wires and cables shall be separated at least ___ inches from conductors of any electric light, power, Class 1, non-power-limited fire alarm, or medium-power network-powered broadband communications circuits.
2
Outdoor mobile home disconnecting means shall be installed so the bottom of the enclosure containing the disconnecting means is not less than ___ above finished grade or the working platform.
2 ft
The disconnecting means for shore power to a boat shall be readily accessible, located not more than ___ from the receptacle it controls, and shall be located in the supply circuit ahead of the receptacle.
30 inches
Determine the minimum ampacity of conductors serving a continuous duty, Design B, 3-phase, 208-volt, 10 hp, induction-type motor.
38.5 amps
The minimum number of 120-volt, 15-amp lighting branch circuits required for a dwelling that has 70 x 30 ft. of livable space is ___.
4
An RV campground has 150 campsites with electrical power. Twenty-five of the campsites are reserved as tent sites. How many sites are required to have a 30-amp, 125-volt receptacle?
88
For an addressable fire alarm system, the SLCs and devices addresses are supervised by verifying the address of each device. The device address data is polled by the fire alarm panel Central Processing Unit (CPU) at least every ___.
90 seconds
A 120/240-volt, 1-ph, 3-wire panel is fed from a 50 KVA 1Ø transformer that has Z = 2.3% on its nameplate. If the two ungrounded conductors are connected together using a 4/0 AWG THHN/THWN copper jumper, ___ amps of current will flow through the 4/0.
9058
A 120/240-volt, 1-ph, 3-wire panel is fed from a 50 KVA 1Ø transformer that has Z = 2.3% on its nameplate. The transformer is supplied power from a 2-pole breaker in a 277/480-volt, 3-ph, 4-wire panel. If X1 and X4 are connected together using a 4/0 AWG THHN/THWN copper jumper, ___ amps of current will flow through the 4/0.
9058
A device installed in a PV source circuit or PV output circuit that can provide an output dc voltage and current at a higher or lower value than the input dc voltage and current is known as a(n) _____.
DC-to-DC converter
A Square D transformer with a nameplate rating of 240/480-V pri — 120/240-V sec can be connected to a 2-pole breaker in a ___ panelboard and deliver nameplate-rated voltage to a load.I. 120/208-V 3Ø, 4-W II. 480/277-V 3Ø, 4-W
II only
