BUILDING ELECTRICAL SYSTEM Flashcards
(103 cards)
1
Q
There are many possible electrical systems that can be used to distribute power in a building. (True or false)
A
True
2
Q
Typically, system design begins with selection of a _________________, which is dependent on sizes and types of the connected loads, utilities near the building, local codes and ordinances, economics, and safety.
A
building system voltage
3
Q
means a ground-mounted or roof-top distributed ______ generation system designed and installed for residential applications, which is leased by, or subject to a ______________ agreement with, the owner of a residence for the purpose of generating Electricity for that residence
A
residential systemS, solar, power purchase
4
Q
is a single building set up to has accommodate more than one family living separately. That can range from a duplex, which two dwellings within a single building, to homes or small apartment buildings with up to _____ units.
A
multifamily dwelling, four
5
Q
Multifamily dwelling units (e.g., apartments, condominiums), power is brought from a ______________ to the building service equipment. It is then divided at a main distribution panel, passes through individual meters, and is distributed to the individual dwelling units through _________.
Each dwelling unit is served by a separate __________ located in the dwelling unit. Branch circuits extend from a panelboard to feed outlets within the unit. A ___________ has branch circuits that serve common areas (e.g., corridors, laundry rooms, lobbies, and so forth).
A
utility transformer, feeders, panelboard, house panelboard
6
Q
Large commercial and industrial facilities have large and _____ power requirements that necessitate different types of systems for different building occupancies.
Essentially there are so many variations that there is no standard type of system. In a typical large building, electrical power is provided to a transformer located outside the building or it enters a transformer vault located at the ___________ in the building.
A
commercial/industrial systemS, varied, service level
7
Q
Lines serving a residential development being buried in a trench.
A
underground electrical distribution
8
Q
lines readied for connection to exterior transformer
A
underground distribution lineS
9
Q
a _______ V- _____ A, underground service entrance for a single- family residence
A
Electrical Meter, 120/240, 150
10
Q
underground service entrance for a multifamily dwelling unit
A
electrical meter for multifamily dwelling unit
11
Q
a service entrance with the electrical meter and main disconnect (below meter and above circuit breakers). Circuit breakers are properly marked on the panelboard face.
A
Electrical Meter and Main Disconnect
12
Q
_______________ are the most common conductor materials used in building electrical wiring, although other materials can be used.
A
Copper and aluminum
13
Q
As a general rule, solid copper conductors are used in small conductor sizes (up to about ___ AWG) because safety issues associated with aluminum are avoided and weight and cost are significantly affected.
A
False: not affected significantly,8
14
Q
__________________ are widely used on larger (above 30 A) circuits serving large motors, equipment, and appliances.
A
stranded aluminum conductorS
15
Q
Conductors are covered with ____________ to provide electrical isolation and physical protection of the conductor material.
The type of ___________ material determines the environment in which a wire or cable can be used safely.
A
insulation x2
16
Q
Insulators like __________ and _________ are used as a covering for electric wires.
This makes electric wires safer to handle because the insulator protects you from the current.
A
plastic and rubber
17
Q
In building electrical systems, the __________ of a conductor may need to be adjusted with correction factors when conditions related to the temperature of the surroundings and the number of conductors in a raceway (e.g., conduit or cable) fall outside normal operating ranges.
Correction factors typically applied are addressed in the following sections. The succeeding tables contain ampacities for various conductors, conductor insulations, and sheathings.
Ampacities provided in these tables are values based on a normal operating temperature of __°F (__°C).
A
ampacity, 86, 30
18
Q
Ampacity values for each conductor ______ are for different equipment ________ (where connections of wiring are made) temperatures.
A
size, terminal
19
Q
________________ is the temperature of a surrounding medium (e.g., air, soil).
In the case of electrical wiring, it is the temperature of the ______________.
A
Ambient Temperature, medium surrounding
20
Q
As ambient temperature decreases, less CURRENT GENERATED HEAT is needed to reach the temperature rating of the insulation. Therefore, ampacity is governed by contribution of ambient heat.
A
FALSE : decreases-rises
21
Q
The ________________ of a conductor refers to the normal temperature RANGE in the environment in which that conductor is to be used (e.g., the temperature of the surrounding air, water, or earth).
A
ambient temperature rating
22
Q
v Conductor ampacity is adjusted for changes in ambient temperature, including temperatures below 78°F (26°C) and above 86°F (30°C).
v A _________________ factor (Ft) for conductors is applied based on the ambient temperature of the conductor.
Example:
A
temperature correction
23
Q
When several current-carrying conductors are contained in a raceway or cable, the temperature of the conductors will increase under normal loading conditions.
A ____________________ (FN) must beapplied for _____ or more conductors in a raceway or cable installed in the same raceway or conduit or any bundled cables that are more than ____ in (_____) long.
A
bundling correction factor, four, 24 in., 0.63m
24
Q
In addition to ampacity requirements, _____________ and ___________ should be analyzed for _____________ because of adverse effect it can have on performance and operating life of appliances and equipment.
Total voltage drop in the feeders and branch circuits should not exceed __%
A
branch circuits, voltage drop, feeders, 5
25
The percentage of voltage drop is determined by the ratio of _____________ and _______________.
voltage drop , system voltage
26
Insulation Color Coding & Identification Markings
_______________ requiring color identification are marked at the _____________ with a hand-painted stripe or colored tape wrapped around the conductor insulation.
Larger conductorS, terminal endS
27
The __________ (ground) conductor insulation must be color coded _________, _________ with one or more ______ stripes, or may be a bare conductor on small conductors in cables.
grounding, green, green, yellow
28
The North American standard for color coding is _______ or any color, except white, gray, and green (ungrounded/hot); white (grounded/neutral); and green (ground).
black
29
All building wiring must be enclosed in a cable, conduit, wireway, or raceway.
TRUE
30
During installation of wirings, conductors are _____ through conduit or tubing, are _____ in a wireway, or are ________ in cables, and secured to _________ framing.
snaked, laid, contained, structural
31
Conductors that are run through a raceway must have sufficient ______________ to prevent overheating.
open-air space
32
A current-carrying conductor found in a raceway is any ungrounded conductor or grounded conductor.
___________ (bare or green colored) and shared neutral conductors are not current carrying and are not counted.
Equipment grounding
33
are favorite raceway materials used to protect conductors in all types of buildings.
Rigid conduit and tubing
examples:
rigid metal and nonmetallic conduit
IMC
EMT
ENT
34
bends of materials used in raceways must be made no smaller than the minimum radius specified by code, about __ to __ times the conduit diameter.
6, 8
35
Conduit and tubing can have up to four __° bends or the equivalent ___° total in one run.
90, 360
36
In runs requiring more bends, a _______ is added in the run to assist in pulling conductors and to allow access.
pull box
37
Three flexible conduit, offers the advantage of easier installation and can be salvaged easily when circuits are rearranged.
It is used where _________ protection is needed and easy relocation of equipment is desired.
It can have up to _____ 90° bends or the equivalent (360° total) in one run.
flexible metal conduit
liquid tight flexible metal
nonmetallic conduit
mechanical
4
38
________ should be supported to prevent wearing away against structure and to avoid stressing its end fittings.
Conduit
39
§ ______ conduit and tubing must be supported within __ ft of a box or other connection and at intervals of __ ft (about 3 m).
§ Continuous, ___________ can be used as the grounding conductor.
§ Flexible conduit must be supported every __ to __ in (1.35 m) and within __ in (300 mm) of a box, except up to __ in (about 1 m) is allowed at usage points where flexibility is required (e.g., a pump motor or air conditioner condensing unit) and __ ft (about 2 m) between a recessed light fixture and a box.
Rigid, 3, 10, metal conduit, 4, 6, 12, 36, 6
40
- ____ and ____ can be used as grounding conductor if it is continuous and properly bonded.
- It is required for flexible conduit.
- It can be bare or insulated.
Grounding Conductor, IMC and EMT
41
Cannot be use as the grounding conductor.
Manufactured from _________ that have very high rates of thermal expansion (over 6 in for a 100°F temperature change per 100 ft/over 300 mm in a 50°C temperature change per 30 m).
ü Provisions must be made if it is exposed to significant temperature changes.
Rigid nonmetallic conduit and tubing (ENT), thermoplastics
42
Permitted in single- and multifamily dwelling units and some other buildings.
ü Restriction of use in:
ü Underground
ü buildings that are more than three stories above grade or in commercial
ü garages
ü Motion picture studious
ü Theaters
ü Places of assembly
ü Elevator hoist ways
ü Other corrosive or hazardous locations
NM and NMC must be supported every 4-6(1.35 m) and within 12 in (300 mm) of a box
Non-metallic sheathed cable (NM and NMC)
43
Is for use in dry, indoor applications.
ü Restriction of use in:
ü commercial garages
ü Motion picture studious
ü Theaters
ü Places of assembly
ü Elevator hoist ways
ü Other corrosive or hazardous locations
Bends are limited to no less than ____ times the diameter.
Armored Cable ( AC)
44
§ _______ and ______ should be installed away from locations where building occupants might use it as a handhold or footstep.
§ __________ should be provided at the lowest point in a conduit run.
§ ________ and ________ burrs should be carefully removed to prevent damage to conductor insulation.
§ It must be supported every __ to __ in (1.35 m) and within ___ in (300 mm) of a box, except up to ___ in (600 mm) is allowed at points of usage where flexibility is required (i.e., at a pump motor).
§ AC can be embedded in masonry, concrete, or plaster.
Cable and conduit
drain holeS
drilling and culling
4,6,12,24
false, can-cannot
45
§ All electrical connections must be made in a protective ____________ such as panelboard, junction, or device box, fixture, or appliance.
§ Every switch, outlet, and connection must be contained in an __________ and every lighting fixture must be mounted in a box.
§ All wirings must begin or terminate at a panelboard or in a box that is housing switch, luminaire connection, receptacle, conductor junction, or some similar terminal fitting.
§ ____________ must be mounted so that the blank cover plate is visible and readily accessible.
§ All electrical boxes must be adequately secure to the building structure.
enclosure, electrical box, junction boxes
46
Any box can be used for any purpose.
§ There are no requirements that specify that a certain type of ______________ be installed for a specific purpose.
§ Typical trade practice:
ü ________ and __________ boxes for lighting outlets
o Normally installed overhead for lightning installation.
ü ______________ and ____________ for switches and receptacle outlets
electric box
round, octagonal
rectangular, square
47
The _____ and ________ of conductors to be installed in a box influences selection of type of box and box size.
§ The more conductors and/or the conductor size, the bigger the box must be.
§ The capacity of a box, in cubic inches, is determined by its length, width, and depth.
§ An increase in one or more o these dimensions increases box capacity.
ü Some boxes are designed so they can be ganged together to increase box capacity.
§ By convention, a conductor that runs through the box is counted as one conductor and each conductor that terminates in the box counts as one.
§ Fixture wires and conductors that do not leave the box, such as an internal grounding wire, are NOT COUNTED.
§ One conductor is _________ for one or more grounding conductors that enter the box.
§ __________ in an electrical box must have air space to prevent sufficient open overheating.
size, number, deducted, conductors
48
A building electrical system consists of several circuits that extend out from the switchboard or panel board. A __________ is that portion of the building wiring system that extends _____ the final over current protection device that is protecting the circuit.
Branch Circuiting, branch circuit, beyond
49
BRANCH CIRCUITING
§ It provides power from a circuit breaker or fuse in the panel board to single or multiple points of use called outlets.
§ An ________ is a point in a wiring system where current is taken to supply an appliance, piece of equipment, or lighting installation.
§ A branch circuit is composed of an ________________ (fuse or circuit breaker), wiring, and one or more outlets.
outlet, overcurrent protection device
50
This of branch circuit serves ONE RECEPTACLE or piece of equipment such as for a range, clothes dryer, large copy machine, or other piece of machinery. These circuits usually lead directly from the distribution panel to the appliance and do not serve any other electrical devices. The ______________ is sometimes known in the trade as a dedicated or __________________.
individual branch circuit x2, special pupose circuit
51
A branch circuit supplies two or more outlets for _______ 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. There are usually a number of __________ branch circuits supplying lights and outlets in different rooms around a residence, commercial or industrial building.
General Purpose Branch Circuit, lighting
52
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 do not supply lighting fixtures. Appliance branch circuits cannot exceed 20 A
Appliance Branch Circuit
53
A branch circuit consisting of two or more UNDERGROUNDED (hot) CONDUCTOR having a voltage between them and a common neutral (grounded) conductor that is shared between the ungrounded conductors such as in a 120/240 V three-wire circuit. Other branch circuits specific to a particular occupancy may also be required. For example, the following branches are required in health care facilities such as hospitals, nursing homes, and dental facilities.
Multiwire Branch Circuit
54
An EMERGENCY of feeders and branch circuit that provides adequate power to patients and personnel. It must automatically connect to an alternate power source such as a generator when the normal power source is interrupted.
Life Safety Branch Circuit
55
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 source is interrupted.
Critical Branch Circuit
56
__________ duplex receptacles are fed with a 120/240 V circuit having two ungrounded (hot) conductors, a grounded neutral conductor, and a grounding conductor.
- One grounded (hot) conductor feeds power to _______ outlet and the and the other ungrounded (hot) conductor feeds the ______ outlet.
- The ____________ (neutral) conductor is shared between both circuits.
- _____________ allows power to be drawn from two separate circuits on one duplex receptacle.
split wired, upper, lower, grounded (neutral), split wiring
57
BRANCH CIRCUIT RATINGS AND LOADINGS
v The branch circuit rating is determined by the rating of the ______________________ (fuse or circuit breaker) used to protect the wiring in the circuit from excessive current flow.
v The wiring in the circuit must safely deliver current to the connected load and the over current protection device protects this wiring, so the circuit rating matches the rating of the over current protection device.
v 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.
v Design of a building electrical installations computations with power (P), expressed in Watts (W); voltage (E), in volts (V); amperage (I), in amps (A) and volt-amps (VA) in volts and amperes.
v All electric-resistant appliance or pieces of equipment such as an oven, water-heater and space- heater (no blower) and lights generally have power (wattage) ratings _____ to their connected loading (VA rating).
v In contrast, all _________________ (having a motor) appliances or pieces of equipment generally will have a VA rating ______ than the power (P) rating.
Design of a branch circuit involves _______ conductors and over current protection (fuse or circuit breaker) that match the _______________.
overcurrent protection device, connected load,equal, electromechanical, larger, sizing, circuit rating
58
_____________________ feed more than one outlet for lighting or other purpose. According to requirements, the rating of general purpose branch circuits must be 15 A, 20 A, 30 A, 40 A, or 50 A. Maximum connected loads, voltages, and other requirements for general purpose circuit ratings are shown in Table 19.11.
_______________ typically provide power to convenience receptacles and lighting outlets with ratings of __ A and __ A because of their ease of running and pulling the ______ conductors required (No. 12 AWG and No. 14 AWG copper, respectively).
General purpose circuits, 20, 15, slender
59
General purpose circuits are typically limited according to what will be connected to them:
Ø When a general purpose circuit feeds fixed appliances and luminaires or portable appliances, the total of the fixed appliances should be no more than ___% of the branch circuit rating.
Ø When portable appliances will be used on a general purpose circuit, the limit for any one portable appliance is ___1% of the branch circuit rating.
In commercial applications, convenience receptacles are computed at a load of _____ A per receptacle and are limited to ____ % of the rating. This limits a branch circuit serving only receptacles to its rating divided by 11/2 A.
When the load on the circuit will be a CONTINOUS OPERATING LOAD, the total load should not exceed ____ of the circuit rating.
50, 80, 1.5, 80
60
These circuits provide power to a single outlet such as a receptacle serving a range, clothes dryer, or copy machine. Although there are no size limitations for an __________ rating, appliances and equipment rated at above 25 A must be placed on a separate individual circuit because of the __% maximum single load limitation in general purpose circuiting. Usually connected loads above 20 A are placed on an individual circuit. It is good practice to provide individual circuits for loads above 1500 W. Motors above 1/8 hp should also be placed on an individual circuit.
individual circuitS, 50
61
These circuits serve two or more outlets to which ONLY APPLIANCES are connected. In dwelling units, two or more 20 A small appliance circuits for convenience receptacle outlets in the kitchen, dining room, pantry, and breakfast room are required. These are in addition to the other outlets required. Small appliance circuits can supply any refrigerators and freezers, but not an electric range or oven.
appliance circuits
62
o A ____________ is a connected load thatoperates for 3 hr or more at any time. Many electrical loads fit within this category such as circuits serving office and classroom lighting installations. When determining a circuit rating, most loads deemed continuous must have a circuit rating calculated at ____% of the circuit's connected load.
The intent behind the _____% factor is from the inability of the overcurrent protection device to handle a continuous load without overheating; that is, most circuit breakers trip if they carry their rated load for any significant time period.
Another way of looking at this is that the connected load on a continuous load circuit should not exceed ____% of the individual circuit rating. Thus, the maximum continuous load on a 20 A circuit of 16 A.
continuous load, 125, 80,
63
Branch Circuit Conductor Size
On a branch circuit, conductor ____ is tied to circuit rating.
size
64
Residential Branch Circuit Wiring
Type ________ cable (e.g., Romex®) is the most widely used wiring method in residential dwellings. ___ cable must have 194°F (90°C) conductor insulation rating, which is designated by a "B" on the cable sheath. Typically, AWG No. __, and AWG No. 14 are used for receptacle and lighting circuits.
NMB, NM,
65
REQUIREMENTS FOR SWITCHES
01. ___________ must be selected to match the load they control.
02. A panelboard-like enclosure called ____________ is used in large lighting installations that require many switches.
03. ____________ must be selected to match the appliance or equipment they serve.
04. Ordinary convenience receptacles and switches are general ____________ and there are no specific height requirements for switches and receptacles.
05. Normally, switches are mounted approximately ____ in. (1.2 m) above finished floor (AFF), convenience receptacles at __ in. (400 mm) AFF and convenience receptacles in bathrooms and restrooms at __ in. (1.1 m) AFF, unless otherwise specified.
06. Receptacles are customarily installed with the _______ slot oriented ________.
07. Unless the receptacle is controlled by a switch, the receptacle is frequently aligned with the grounding slot ________.
08. Ordinary convenience receptacles and switches are general wall mounted and there are no specific height requirements for switches and receptacles.
09. In contrast to historical practice, it is recommended that receptacles be installed with the grounding slot oriented ______ to improve safety.
10. By orienting the grounding slot upward, the __________ would be the first blade to contact the object, which would not create a short-circuit.
1. Switches
2. lighting control panel
3. ReceptacleS
4. wall mounted
5. 48, 16, 44
6. grounding, downward
7. upward
9. upward
10. grounding pin
66
o An overcurrent protection (OCP) device, a fuse, or circuit breaker serves to LIMIT current levels in a conductor by interrupting power when current limitations are exceeded. It prevents excessive heat from damaging conductors and related equipment.
true
67
The ____________ of a fuse or circuit breaker must be equal to or greater than the voltage of the circuit in which the fuse is applied.
voltage rating
68
The current carried (amperage) by the electrical circuit or system protected by an OCP device must exceed the maximum current rating of the circuit breaker.
false, it must not exceed
69
The __________________ (AIC) rating for circuit breakers should be at least _______ A and ___________ A for fuses.
amperes interruption current, 5000 , 10000
70
The fuse or circuit breaker must be installed at a location in the circuit where the conductors ________ power (generally at the panelboard).
receive
71
The OCP device must protect the ____________ conductors in a circuit to ensure that power to the circuit is interrupted by the OCP device.
ungrounded
72
Lastly, the __________ (grounded) and ________ conductors are not protected by overcurrent protection
neutral, grounding
73
A _______ is a set of conductors that carry a comparatively large amount of power from the service equipment to a second panelboard, called a __________, where branch circuits further distributes the power.
Feeders must be designed to provide sufficient power to the ________________ they supply so feeder conductor size is based on the maximum load to be supplied by the ________.
Feeders should be capable of carrying the amount of of current required by the _____, plus any current that may be required in the future.
It is not likely that all connected loads on a feeder will be in operation at a specific time. Thus feeder conductors do not need to be sized carry the total __________ served by the feeder.
Additional capacity may be warranted for future
feeder, subpanelboard,
branch circuits, feeder
load
connected load
74
Switchboards and panelboards can be used as _________ equipment, at a point __________ from the service entrance equipment.
Ø Panelboards feeding lighting and convenience receptacles and having at least ___% of the circuits rated at 30 A or less are identified as lighting and appliance panelboards.
Ø ______________ panelboards feed other panelboards (called subpanelboards), motors, and transformers, but not circuits powering lights and convenience receptacles.
Ø In a single panelboard, not more than ___overcurrent protection devices may be used for protecting lighting and appliance branch circuits.
SWITCHBOARD AND PANELBOARD REQUIREMENTS
distribution, downstream
10
power distribution
42
75
-When locating overcurrent protection in a panelboard, it is important to ________ the anticipated load so that both _________ are carrying a similar load.
-In service equipment panelboards, the neutral and equipment grounding conductors are _________ together. In subpanelboards, the neutral is ________ from ground.
-In general, a fuse or circuit breaker must be installed at a location in the circuit where the conductors receive power.
-Generally, this location is in the _________ or load center before the conductors leave to convey current to the outlets in the circuit.
SWITCHBOARD and PANELBOARD REQUIREMENTS
balance, bus bars
bonded, isolated
panelboard
76
Large enough to supply the compute load of the building or area of the building being served.
Service Equipment
77
- The most common sizes of _________ service equipment are 100, 125, 150, and 200.
residential
78
- All ______________ and electrical panels shall have a clear area __ in (0.75 m) wide and __ in (0.9 m) deep in front.
- The required clearance can be found in the Code. Typically, minimum vertical clearances of ___ ft (5.5 m) above roadways, ___ ft above driveways, and __ft above sidewalks are the required minimum.
service equipment,30, 36, 18, 12, 10
79
Commonly used aluminum conductors.
RHW, THWN, THIN, XHHW, and USE.
80
SERVICE EQUIPMENT REQUIREMENTS
· An ___ ft (2.4 m) clearance is required above low- sloped (less than 4 in 12 slope) rooflines. A __ ft (0.9 m) clearance is required for steep- sloped roofs.
· It is also necessary to bury underground conductors sufficiently below grade to reduce the hazard of unintentional contact.
· The required depth of burial can be found in the Code.
· Minimum earth cover varies from __ to __ in (150 to 600 mm).
8, 3, 6, 24
81
01. Transformer combinations, such as wye-wye (Y- Y), delta-delta (-), delta-wye (-Y), and wye-delta (Y-) are available for use in buildings.
02. The _____ symbol (Y or ) indicates the duration of the primary wirings and the ______ the configuration of the secondary windings.
03. A ______ V primary, ____ VY/____ V secondary, three- phase transformer is a popular unit used in large commercial buildings and industrial facilities.
04. From a four-wire 480/277 V supply, 277 V lighting and 480 V heavy equipment can be powered before being stepped down to a 208 Y/120 V, three-phase, four-wire system for convenience receptacles and light-duty equipment and appliances.
Primary and secondary conductors are sized to carry ______% of the ampere rating of the overcurrent protection.
The equipment-grounding conductor size is based on the ampacity of the __________ conductors.
first, second
480, 208,120
100
phase
82
OCCUPANT PROTECTION REQUIREMENTS
· The NEC has required tamper-resistant receptacles be installed in all ___-V, __- and __-A electrical receptacles in hospital pediatric areas for nearly three decades. Recently, the NEC introduced requirements. for all 125-V, 15- and 20-A electrical receptacles in new residential construction to be tamper-resistant receptacles.
· Products such as plastic plug-in inserts and ______________ with contact shutters are available for tamper resistance, but do not meet these requirements.
· There are many other settings where children may be at risk, including; day care centers, children's play areas, elementary and nursery schools, doctor's offices and lobbies, and retail establishments featuring children's attire or toys.
· All tamper-resistant receptacles must have either the words "______________" or the letters "TR" (minimum ____ in or __ mm high) on the device as a clear indication that this is a tamper-resistant receptacle.
125, 15-20, wall plates, tamper resistant, 3/16, 5
83
GROUND FAULT CIRCUIT PROTECTION
· The NEC introduced requirements for use of GFCI in residences in ______ when it required GFCI protection of outdoor convenience receptacles within __________ (2 m) of grade level. In residential Installations, GFCI protection is required at all _____V, single phase 15 A and 20 A outlets in the locations listed below.
The requirements do not apply to equipment rated at _____ V (e.g. baseboard heater, room air conditioners, welding receptacles, or other outlets that are not rated at 125 V)
1973, 6.5 ft, 125
240
84
The NEC introduced these requirements beginning in the years listed:
§ Outdoor convenience outlets within 6 & 1/2 ft or (2 m) of grade level (________ edition) and revised to include all exterior convenience outlets (______ edition)
§ Bathroom convenience outlets (______ edition)
§ Readily accessible convenience outlets in garages (_____ edition), except where not readily accessible such as outlets dedicated to an overhead door opener or freezer
§ Convenience outlets within ___ ft (1.8 m) of kitchen sink (______ edition) and revised to include all kitchen convenience outlets that serve countertops, including islands (1996 edition) but not those serving fixed kitchen appliances (e.g. range and oven) and the refrigerator or freezer
§ Convenience outlets in unfinished basements and crawl spaces, except laundry (_______ edition)
§ Convenience outlets within 6 ft (1.8 m) of laundry, utility room, or wet bar sink (______ edition)
1973, 1993
1975
1978
7, 1987
1990
1993
85
Some types of equipment (e.g., appliances with large motors) have inherent leakage current levels that exceed the standard trip setting of a GFCI. This will cause _____________ of GFCI devices.
GFCI circuit ___________ may be added in panel boards of older buildings to replace ordinary circuit breakers. For homes protected by _________, the _________________ or portable-type GFCI protection is highly recommended.
nuisance tripping
breakerS, fuseS, convenience receptacle
86
ARC FAULT CIRCUIT PROTECTION
§ Future editions of the Code will likely expand coverage to include commercial and industrial applications such as use in fire station sleeping areas, military housing, hospitals, outpatient clinics, rest homes, retirement homes, and in other locations where ___________ or cord- connected equipment may be used and where the _____________ may be at risk from arc faults.
§ Buildings wired with solid _________ conductors used in the late 1960s and early 1970s are prone to poor connections. Such building electrical systems can also be retrofitted with AFCI protection to identify faulty connections.
extension chords, general occupancy
aluminum
87
PRELIMINARY DESIGN GUIDELINES
§ Ideally, the ________________ should be involved in the of the project from the very beginning.
§ The _______________ is the person who could best discuss the electrical component of project planning with the power company.
§ Checking of all of the utilities (whether sewer, water storm sewer, natural gas lines, and so forth) is needed early in the design stage.
electrical designer
88
Before actually beginning the design layout of the project, the designer will need to accumulate certain information:
01. Determine whether electrical service is available at the site, and what type of _____________ is available (e.g., 120/240 V AC, 10-3W, 208 Y/120 V AC, 3 -4W, and so forth).
02. Obtain a list from the owner of all the types and locations of equipment and appliances to be used in the building that will require electricity.
03. Work with the ___________________ to best locate all of the electrical equipment and appliances on the floor plan.
04. Review with the architect where the basic mechanical equipment (e.g., HVAC and plumbing), the service entrance equipment, the power and lighting panels, and the conduit or cable will be located.
05. Discuss with the owners any future plans for changing or expanding the facilities (e.g., remodeling, constructing additions or other buildings, future equipment requirements) and anything else that could potentially affect the size and location of the electrical service.
1. system voltage
2.
3. architectural designer
4.
89
Basic Design Considerations
_________ guides the designer to a solution that best suits the need of the building occupant. The designer achieves a solution by:
Ø Observing and evaluating existing installations and adapting them to meet the project requirements
Ø Applying electrical systems theory
Ø Applying ______ requirements
Design of an electrical system begins with the layout of all _________ or outlet connections.
Experience, code, outlets
90
Design Guidelines for Common Spaces
ü The number and type of _______________ should be fitted to the various seeing tasks.
ü All convenience receptacles on ___ A and ___ A general purpose circuits should be of the __________ type, minimizing the hazard of shock from short circuits.
ü GFCI protection should be provided on convenience receptacles where required by occupant is exposed to ________).
ü AFCI protection should be used on convenience receptacles where required by __________ (e.g., in bedroom circuits).
All rooms that have more than one entrance should be equipped with ____________________ (e.g., two-way or three-way switching) at each principal entrance. If this recommendation would result in the placing of switches controlling the same lighting installation within ___ ft (2.5 m) of each other, multiple-switch controls may not be required.
ü ___________ should be located at the lockset or latch side of doors or at the traffic side of arches, and within the room or area where the lighting outlets are located.
ü 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 ___ ft (1.8 m) from an outlet in that space. The intent is to eliminate cords having to pass over hot or conductive surfaces wherever possible.
lighting outlets, 15, 20, grounding, water, local code, multiple-switch controls, 8, wall switches, 6
91
BUILDING EXTERIOR
ü One or more ____________ should be located at or near all exterior entrances. Outlets should be switched or automatically controlled.
ü For each single-family dwelling, at least one ______________ shall be installed outdoors to be readily available from ground level.
ü One or more outlets may be required for exterior equipment (e.g., swimming pool pump, well pump, and so on).
lighting outlets, duplex receptacle
92
Common Areas and Living Rooms
ü Outlets for ambient and task lighting should be provided. General illumination outlets should be ___________ controlled.
ü Convenience receptacles in living areas should be placed so that no point along the floor line in any usable wall space is more than ___ ft (0.6 m) from a receptacle outlet in that space.
ü One or more receptacles for entertainment equipment should be provided at bookcases, shelves, or other suitable locations.
ü When general illumination is to be provided from ___________, then at least two separate wall- switched plug-in positions should be provided.
ü An outlet for a fireplace may be required.
ü A smoke detector/alarm on a _____, V circuit should be considered.
wallswitch, 6, portable lamps, 120
93
Food Preparation/Kitchen/Cooking Areas
ü Lighting design should provide for ________ and local/task illumination of the work areas, sink, range, counters, and tables.
ü __________________________ should be provided for all fixed appliances (e.g., range, built-in microwave, exhaust hood, dishwasher, trash disposal unit, waste disposal, and so on).
ü At least two ___ A small appliance circuits for kitchen countertops should be provided. Outlets on these circuits should serve only the kitchen, pantry, and/or dining room areas.
ü Convenience receptacles serving countertop areas (e.g., except behind refrigerator and those serving fixed appliances) should be GFCI protected. It is recommended that receptacles serving countertop areas be ___________.
ü A smoke detector/alarm on a ____ V circuit should be considered.
ambient
special purpose receptacles
20
splitwired
120
94
Sleeping Areas/Bedrooms
ü General illumination should be provided from either ceiling or wall outlets, controlled by one or more ____________.
ü A convenience receptacle should be placed on each side and within __ ft (1.8 m) of the centerline of each probable individual bed location.
ü All _____ V branch circuits that supply outlets in dwelling unit bedrooms must be protected by an AFCI device.
ü A smoke detector/alarm must be provided on a 120 V circuit and should be AFCI protected.
ü In master bedrooms, outlets should be considered for a television and entertainment equipment (e.g., DVD/VCR player).
ü In master bedrooms, an outlet for a fireplace may be required.
wall switcheS
6
120
95
Bathrooms/Restrooms
ü Lighting sources at the ________ should be capable of illuminating both sides of the face.
ü At least one GFCI-protected receptacle within ___ ft of the outside edge of each lavatory basin should be provided.The circuit serving bathrooms should have no other outlets. Where the ___ A circuit supplies only a single bathroom, it can supply power to outlets for other equipment within the same bathroom (i.e., lighting outlets or an exhaust fan).
ü A wall-switched or timer-operated, built-in ventilating fan capable of providing a minimum of __ to ___ air changes per hour per water closet (50 cfm/water closet) should be provided where no natural ventilation through windows is included
ü _______________ should be located so as not to be readily accessible while standing in the tub or shower stall.
mirror
3, 20
8,10
wall switcheS
96
Laundry Areas
ü Outlets for ____________ should be installed to provide illumination of work areas, such as laundry tubs, sorting tables, washing, ironing, and drying centers. Lighting outlets should be wall-switched controlled.
ü In the laundry area, one __ A receptacle for the clothes washer and a special receptacle for the clothes dryer are required.
ü One outlet and one switch for a _____________ should be provided.
ü A smoke detector/alarm on a 120 V circuit should be considered.
fixed lightS
20
ventilation fan
97
Halls/Corridors
ü ________________ should be installed for proper illumination of the entire area with particular attention paid to irregularly shaped spaces.
ü Convenience receptacles in hallways within a dwelling unit should be placed so that no point in the hallway shall be more than __ ft (1.0 m) from a duplex receptacle. Each hall over __ ft2 (2.3 m2) in floor space should have at least one receptacle.
ü In _______________, convenience receptacles should be placed so that no point along the floor line in any usable wall space is more than ___ ft (3.1 m) from a receptacle in that space.
Ceiling fixtures, 10, 25, entrance foyerS, 10
98
Stairways
ü _____________ or _______________ should be installed to provide adequate illumination of each stair flight
ü Outlets should be so arranged that the stair system can be fully illuminated from either floor.
ü A smoke detector/alarm on a 120 V circuit should be considered at the top of the stairs.
fixed wall, ceiling lighting outlets
99
Utility Rooms Lighting
ü outlets should be placed to illuminate the ______________ area and ___________. At least one lighting outlet should be wall-switch controlled.
ü Convenience receptacles should be provided.
ü ___________ should be provided for each piece of ___________ equipment requiring electrical connections such as the boiler, chiller, furnace, water pump, or compressor.
ü A ________________ may be required for an electric-resistance water heater, and/or an electric-resistance furnace.
furnace/boiler, work area, outlets, mechanical, special purpose outlet
100
Shops/Garages
ü Lighting outlets should be placed to illuminate the work areas. ___________ should be provided above ___________. Lighting outlet should be wall-switch controlled
ü At least one ______________ should be provided for each space in a garage or carport.
ü Convenience outlets should be provided at workbenches. In garages or near water, these outlets should be GFCI protected.
ü Outlets should be provided for automatic _______ (garage door operators in the ceiling above each bay
ü Special purpose outlets should be provided for special equipment such as air compressors, welding equipment, tire changer, dust collection equipment, machining equipment and so on. Check with owner on equipment voltage requirements, load, and placement.
ü A smoke detector/alarm on a 120 V circuit should be considered
work-benches
task lighting
duplex receptacle
overhear
101
Storage Rooms/Closets
ü Generally, one lighting outlet for each large closet or storage room should be provided.
ü Wall switches or automatic door switches are preferred, but _____ switches are acceptable.
pull
102
Electrical/Telecommunications Closet
ü Lighting outlets should be placed to illuminate the area
ü A minimum of ____ dedicated convenience receptacles on separate circuits is required. Additional duplex convenience receptacles should be placed at __ ft (1.8 m) intervals around the perimeter.
ü Rooms should be located away from sources of _________________.g., transformers, motors, x-ray equipment, induction heaters, arc welders, radios, radar systems, and so forth).
ü ______________ should be considered and supplied.
ü A smoke detector/alarm on a 120 V circuit should be considered.
two, 6
electromagnetic interference
emergency power
103
ü _______________ involve computing the demand load for a building system or a distribution system extending from a panelboard.
ü This load includes the total of all general lighting, appliance, and equipment loads in the building.
ü The _________ allowed by the code takes into account that all of the electrical connections will not be in use at one time
Load computations
demand load
