chapter 24 Flashcards
What do electrical prints include?
Electrical prints include pictorial drawing, electrical layouts, schematic diagrams, and line diagrams.
A drawing that shows the length, height, and depth of an object in one view. These drawings indicate details such as holes and shoulders of an object as seen by the eye.
Pictorial drawings
A drawing that indicates the connections of all devices and components in a residential electrical system.
electrical layout
An electrical layout typically indicates the devices and components of a system with _______.
rectangles or circles
An assembly of conductors (wires), electrical devices (switches and receptacles), and components (lights and motors) through which current flows.
electrical circuit
What stops current from following in a circuit?
a broken wire, a loose connection, or a switch in the OFF position stops current from flowing in a circuit.
What are the five basic parts of a residential and electrical circuit?
- A component (load) that converts electrical energy into some other usable form of energy such as light heat, motion.
- a source of electricity.
- Conductors to connect the individual devices and components.
- a method of controlling the flow of electricity (switch)5. Protection devices (fuses or circuit breakers) to ensure that the circuit operates safely within electrical limits.
All residential circuits use the ___ as the power source for the dwelling.
service panel
the wires pulled through conduit or metallic and nonmetallic cables.
Conductors
What are some examples of control devices?
Single pole switches, three-way switches, motion detectors, timers, or thermostats.
What are typical loads found in a residence?
lamps, motors, televisions, radios, and appliances
What is the typical overcurrent device used to protect a residential electrical circuit?
Circuit breaker
Flipping a single-pole switch to the ON position allows current to pass from the ________, through the closed contacts of the wall switch, through the lamp, and on through the _________, forming a complete (path) or ____.
hot conductor
common conductor
circuit
What is used to control a sump pump?
A float or pressure switch
Current must flow from the power source, through the load, and ___________, making a complete circuit.
back to the power source
These automatically detect the absence of light and respond by sending commands to loads (lights). A ____ responds to the absence of light by turning lights inside and outside a dwelling on and off.
Photo cell
How is a photocell controller mounted?
to standard octagon electrical boxes or directly to controlled lighting.
is a drawing and list that indicates the devices to be used, the location of the electrical devices, and wiring methods.
electrical plan
Electrical plans indicate the use of switches, lights, and receptacle with ______.
Symbols
Understanding _____ is the key to understanding electrical plans.
electrical device symbols
What does a good electrical plan include?
the location of all major electrical devices and connections
These are also used to determine the number of openings in walls and ceilings and to estimate the amount of wire and conduit that is required for the job.
Electrical plans
A complete electrical plan or set of plans is developed into two main parts:
Component plans and wiring plans
Is a group of schedules that state the required locations for receptacles, lights, and switches according to the NEC and local codes.
Component plan
Is a list of electrical equipment indicating manufacturer, specifications, and the number of room or area.
component list
A partial component list is a _____.
component schedule
a drawing that indicates the placement of all electrical devices and components and the wiring required to connect all the equipment into circuits.
Wiring plan
What is the purpose of a wiring plan?
The purpose of a wiring plan is to group individual electrical devices into specific circuits.
Are the basis for all electrical work performed at a residence.
electrical plan
A wiring plan is essential when determining the number of components per circuit (load) and the best route for ___.
wire
Time spent studying a wiring plan aids in anticipating problems and reducing__________.
The amount of materials required.
What do slash marks indicate?
Slash marks indicate the number of conducting wires in cables or conduit.
What does an arrow symbolize?
The circuit connection to the service panel
Indicate the size of wire that must be used and the amount of overload protection that must be provided. The specifications set by manufacturers must agree with or surpass the standards of NEC.
Manufacturer specs
Electrical components are installed in locations typically shown on the ______.
Floor plans
Can help to clarify the approximate location of all switches, receptacles, and light fixtures.
Isometric drawing (construction layout)
Component layouts are directly coordinated to the _______________ which includes the stud and walls and electrical boxes.
actual construction layout
Is a drawing that indicates how the component parts of a circuit will be connected to one another and where the wires will be run.
Electrical layouts
In many cases, wire runs shown at right angles on the wiring layout could have been run diagonally in the room to ______, which results in _______.
conserve wire
lower insulation costs
Provide key points for the construction of an electrical circuit by providing detailed representations of how each component is actually wired into the system.
Exploded views
When component wiring is duplicated, the component can be given a _________ to indicate the device is wired exactly the same way.
letter designation
Although it is assumed that conduit is being used in most construction layouts, all circuits can be wired with _______ or ______.
metallic sheathed cable
non metallic cable
Electrical connections must be what?
mechanically and electrically secure
What solder is commonly used in electrical work?
an alloy of 60% and 40% lead.
The amount of __ determines the strength of the solder and the amount of __ determine the melting point of the solder.
lead
Is added to solder to clean metal surfaces and ensure the solder adheres to the metal surface. Removes oxides and other small impurities from metal surfaces to improve connection.
Flux
What are the two most common types of solder?
Rosin core and Acid core
Is preferred on small electrical applications because the flux is contained within the solder.
Rosin core solder
Must never be used on electrical connections because it corrodes electrical connections.
acid core
Plastic tape, which insulates against voltages up to ___ per wrap, is typically used for residential wiring.
600 V
Are designed to hold several electrical wires firmly together and to provide an insulating cover for the connection.
Wire nuts
What determines the size of a wire nut?
The size of a wire nut is determined by the number and size of wires (conductors) to be connected.
What is used to indicate the maximum number of conductors allowed per connection?
color coding
Is a preprinted peel-off sticker designed to adhere to insulation when wrapped around a conductor. Resist moisture, dirt, and oil and are used to identify conductors that have the same color but different uses.
Wire marker
The joining of two or more electrical conductors by mechanically twisting the conductors together or by using a special splicing device. Must be able to withstand any reasonable mechanical strain that might be placed on the connection.
Splices
A measurement of the amount of current a wire can carry safely.
Wire amperage
What are typical residential wire splices?
pigtail, western union, T-tap, and portable cord splices
Splice is made by twisting two ends of wire together.
pigtail splice
What must be done when a pigtail splice is taped?
The ends must be bent over so the sharp wire points do not penetrate the tape.
Is a splice that is used when the connection must be strong enough to support long lengths of heavy wire.
Western Union splice
In the 1800s, western union splices were used to repair what?
telephone wires
Is a splice that allows a connection to be made without cutting the main wire. One of the most difficult splices to perform correctly.
T-tap splices
is a weak splice because there is no connector to hold the conductors together. Electrified tape cannot be used so the splice must retain the insulation and outer covering properties of the portable cable.
Portable cord splice
Portable cords with stranded wires can be spliced if the conductors are ______ or larger.
14 AWG
Is required to protect splices from oxidation and to insulate individuals against electrical shock. Provides insulative protection up to 600V
Taping
Once the decision to solder an electrical splice has been made and the insulation has been stripped of wire, the splice should be soldered as soon as possible. Why?
The longer the metal conductor is exposed to dirt and air, the greater the oxidation present on the wire, and the less chance an individual has of achieving a properly soldered connection.
How are metal surfaces of conductors normally cleaned?
With light sandpaper, emery loth, or by applying flux surfaces.
Solder is typically in what form?
Wire form
What is typically used to solder?
Soldering gun, soldering iron, or propane torch
Is used to solder large wires or when there is no electricity at the jobsite.
Propane torch
Individuals must apply sold to the splice on the ____ of the point where heat is being applied.
side opposite
Is a device used to join wires firmly without the use of solder.
solderless connector
Split-bolt connectors, screw terminals, back-wired connectors, wire nuts, and crimp connectors.
solderless connectors
Is a solderless mechanical connection used for joining large cables.
Split-bolt connector
Must be made of the same material as the conductors to prevent corrosion.
Split-bolt connector
When dealing with screw terminals since wiring is always attached to electrical equipment with right-handed screws, the wire should be bent around the screw in a _____.
clockwise direction
Is a mechanical connection method used to secure wires to the backs of switches and receptacles.
Quick connectors
How do you remove a wire from a back-wired quick connector?
A screw driver must be inserted into the spring opening next to the connection.
For the most effective use of wire nuts the wires must be twisted together in what direction?
clockwise
How are stranded and solid wires connected together?
When solid and stranded wires are joined together, the solid wire is bent over the stranded wire.
Is an electrical device that is used to join wires together or to serve as terminal ends for screw connections.
crimp connector
Are less expensive and are used where there is no danger of shorting the connector or metal surface.
Non insulated crimp connector
When working with crimp connectors, identification can be a problem, to avoid confusion what is done?
a wire marker is used to identify each conductor
What are the three requirements for solder to adhere properly?
The parts to be solder must be cleaned, fluxed, and hot enough to melt solder for the solder to properly adhere.
Are typically caused by insufficient heat during soldering or the parts being moved after the solder is applied before cooling.
cold solder joints
What is a heat sink or alligator clip?
Is placed between the soldered connection point and component that requires protection. Semi-conductors components such as transistors, and ICs, are very sensitive to heat. This prevents damage.
