Chapter 25 Flashcards
An electrical device used to stop, start, or redirect the flow of current in an electrical circuit.
Switch
The information provided on the back of a switch can be in what form?
color coding
abbreviations
What colors are use to identify screw terminals on switches?
bronze, silver, and green
Power will always come into a switch by the _____and leave the switch by the _____.
common
traveler terminal
What color is the common screw on a switch?
It is usually black or a darker color
What color is the traveler terminal on a switch?
The traveler terminal is usually bronze or silver
What color is the ground terminal on a switch?
The ground terminal is usually green
What inscribe information is on the back of a switch?
- wire to be used
- voltage
- current ratings
A stamped or printed icon that indicates that a device or material has been approved for consumer use.
UL or underwriters laboratories stamp
Underwriters laboratories inc. was created by?
National Board of Fire Underwriters
Indicates the minimum safety requirements and is not meant to serve as a quality comparison between manufacturers.
UL label
What is a CSA label?
is a marking that indicates that extensive tests have been conducted on a device by the Canadian standards association.
Is an electrical symbol that represents copper and aluminum respectively.
Conductor symbol
When a device is marked ___, the device can be used with copper or aluminum wire.
CU/AL
What happens aluminum wire is used with copper connectors?
The typical result is overheating, but electrical fires due to the chemical reaction between the dissimilar metals are also possible.
What is the maximum current rating of a switch for residential use?
the maximum current rating of a residential switch is 15A or 20A.
What is the maximum voltage rating for a residential switch?
120V
What does AC mean?
Alternating Current
Switches used to control loads with a tungsten filament (such as standard incandescent lamps) must be marked with ____.
a letter T
is a special switch information that indicates a switch is capable of handling the severe overloading created by a tungsten load as the switch is closed.
T rating
What happens to the resistance of Tungsten when it is cold?
it is low
What happens to the resistance of tungsten when it is heated?
it increases
At the moment a switch is closed, the low resistance of a tungsten load causes draw to be _____ time the normal operating current.
8 to 10
Once a switch is closed, the tungsten filament (load) heats up and the current flow _____.
drops immediately
The process of heating up a tungsten filament takes how long?
1/240 of a second
Failure to observe the T rating of a switch will do what to the switch?
reduce it’s life expectancy
Where is a strip gauge located on a switch?
on the back rear portion a back-wired switch
A short groove that indicates the amount of insulation that must be removed from a wire so the wire can be properly inserted into a switch.
Strip gauge
When too much insulation is removed, bare wire is left exposed and can cause _____.
A short
What are the common switches use din residences?
single pole, three-way, four-way, and double-pole switches
Is set to the times that the switch is turned ON and OFF.
Timer switch
Allows a sequence of events to be established, such as turning lights ON when no one is home.
programmable switch
Are used as security devices or energy savers.
motion sensor switches.
Is a control device used to turn lights or appliances ON and OFF for a single location.
Single pole switch
What is the hot side of a circuit referred to?
leg
As a general rule, neutral conductors (white wires) are not used as what?
a leg in a switch loop
Not switching the neutral conductor is an easy rule to follow for conduit systems but does not apply to what systems?
Armored and nonmetallic sheathed cable
When armored or nonmetallic cable is used, an identified white conductor can be used as the feeder conductor from the switch. This is approved by who?
The NEC
When using armored or nonmetallic cable a load lamp must be ____.
controlled from two locations
Used in pairs to control light or load from two locations.
Three-way switches
What are the terminals of a three-way switch identified as?
common, traveler A, traveler B
The single terminal at one end of a switch is the ____ terminal.
common
Is easily identified because the terminal is darker than the other terminals or is black.
The common terminal
The positive or hot wire of a circuit is always connected to the ______.
darker terminal
What do the connecting point for the two traveler wires do?
connect paired switches together
A three-way switch is really _______ switches. When the handle is down, contact is made with terminal 1. When the handle is up, contact is made with terminal 2.
two-position switches
Have no ON and OFF markings.
Three-way switches
What is a four-way switch?
A four-way switch is used in combination with two three-way switches to allow control of a load from three locations. One or more four-way switches are used with two three-way switches to provide control of a load from three or more locations.
What is the most popular type of four-way switch?
The through-wired type
Any number of four-way switches can be connected to a circuit, but what rule must be followed?
All four way switched must be connected between two three-way switches.
Two four-way switches can be used and two three-way switches may be used to control a light from four locations, but what rule must be followed?
The two four-way switches must always be wired between the two three-way switches.
What is a double pole switch?
A double-pole switch is a device that consists of two switches in one package for controlling two separate loads.
These switches are designed to disconnect, or connect (open or close) at the same time.
Double pole switches
When are double-pole switches common?
Double-pole switches are common for 230 V circuit where both conductors are hot conductors.
Double-pole switches look similar to four-way switches but they have one distinct difference which is what?
They have ON and OFF markings.
Is a contact device installed for the connection of plugs and flexible cords to supply current to portable electrical equipment.
Receptacles
What does the shape and position of a receptacles slots mean?
The shape and position of a receptacles slots differentiate between 15 A, 125 V receptacle and a 15 A, 250 V receptacle.
This receptacle has connection slots that are vertical and typically different lengths.
A 125 V receptacle
This receptacle has connection slots that are horizontal and the same size.
A 250V receptacle
What is a 125 V receptacle with different sized slots called?
Polarized receptacle
Is a receptacle in which the size of the connection slot determines the plug connection. The short connection slot is the hot connection and the long connection slot is the common connection.
polarized receptacle
What determines the number of contacts and the configuration in which the slots are positioned on a receptacle?
Ratings
What type of plugs are receptacle designed for?
Straight blade or locking type plugs
These receptacles are more common in commercial and industrial applications than residential work.
Locking type receptacles
A silver colored screw on a receptacle indicates what?
neutral terminal
A bronze colored screw indicates what on a receptacle?
not terminal
A green colored screw indicates what on a receptacle?
ground
Receptacles marked with 20 A, 125 V are typically required for ____________.
laundry and kitchen circuits
Typical residential receptacles are marked _____.
15A 120V
Receptacles marked CU are only used for what?
solid copper wire
Receptacle marked CU-CLAD are used with what type of wire?
copper-collated aluminum wire
Receptacles marked with CO/ALR are used with _____.
solid aluminum wire
What are the typical receptacles found in a residence?
standard, isolated ground, split-wired, and GFCI
Include a long neutral slot, a short hot clot, and a U-shaped ground hole.
Standard receptacles
A _____ between the two hot and two neutral screw terminals provides electrical connection between the terminals.
Connecting tab
How do you wire a 120V duplex receptacle?
When wiring a 120 V duplex receptacle, the black or red (hot) wire is connected to the brass-colored screw, and the white wire is connected to the steel-colored screw, and the green or bare wire is connected to the green screw.
Is a standard receptacle that has the tab between the two brass-colored (hot) terminal screws removed. The tab between the two steel-colored neutral screws is not removed.
Split-wired receptacles
What is the purpose of a split wired receptacle?
To provide a standard and switched circuit or two separate circuits at the same duplex outlet.
Is a special receptacle that minimizes electrical noise by providing a separate grounding path for each connected device. These receptacles are identified with an orange color.
isolated-ground receptacles
Is a fast-acting receptacle that detects low levels of leakage current to ground and opens the circuit in response to the leakage.
GFCI receptacles
Any current above the level that is required for a dangerous shock.
ground fault
To properly trim out a switch or receptacle it must be properly covered with a ______.
receptacle cover