Basic Wiring : Chapter 3
Basic Wiring
In this module, we will teach you how to cut, strip, bend, and connect wires. Skip to quiz!
Cutting Wire
When you buy wire, it normally comes in a large round spool. A spool is a very long wire that is wrapped in a coil. You can see an example of a spool in the image to the right.
To begin wiring, we need to make sure that we cut the wire to the correct length. A short wire may not be able to connect two components. A long wire may leave extra room and be unorganized.
To cut wire, we will use a tool called linesman pliers. The bottom part of the plier jaw has two sharp blades that can cut wire.
Before cutting any wire, make sure that you wear safety glasses and gloves. Straighten the wire outside the spool, so you can measure the length. You can use a tape measure to determine the length.
Mark the point that you want to cut the wire at. Insert the wire into the bottom part of the linesman jaws. Close the handles and the wire will be cut.
Stripping Wire
Recall that all wires have a conductive inside. They also have an insulator wrapped around the conductor.
To wire a component, we need to expose some of the conductor. An insulated wire end will not allow current to flow into the next component.
Removing the insulation on a wire is called “stripping” a wire. Stripping the end of a wire allows us to:
Join two wires together, and
Connect a wire to a terminal
We use a wire stripper to remove the insulation from a wire. Wire strippers have several holes in their jaws. Each hole is designed to strip a specific gauge of wire.
For example, look at the wire stripper in the image to the right. If you want to strip a ten gauge wire, you would place the wire in the hole marked “10”.
To strip the wire, place the sheathed wire into the correct hole in the jaws. Close the handles, so the jaws are tightly gripping the wire. Pull the wire and jaws away from each other.
The insulation should be cut and pulled off of the wire. The wire should now have an exposed conductor, like copper.
Bending Wire
You may need to bend a wire into a specific shape. For example, it is common to bend the exposed copper into a hook shape. You can see an example in the image to the right.
You can bend wire with many different types of pliers. Needle nose pliers or linesman pliers are commonly used to bend wire. Recall, needle nose pliers have a long and thin jaw.
To bend a wire, hold the sheathed part of the wire with your non-dominant hand. Place the exposed wire into the tip of the plier jaws.
Close the handles to tightly grip the exposed wire. Rotate the plier handles. This should bend the wire into the correct shape.
Connectors
Sometimes we need to connect two wires together. For example, you may need to connect a wire from one component to a wire from another component. To connect these wires, we use a connector.
There are a few types of connectors which include:
Wire nuts,
Crimp-ons, and
A butt splice
All of these connectors allow us to combine wires.
Wire nuts are one of the most common ways to connect two wires. You can see a wire nut in the image to the right. Wire nuts are used to connect higher voltage wires, for example, 120V wires.
Wire nuts are rotated onto the ends of multiple exposed wires. As the wire nut is rotated on, it locks the exposed wires in place.
To use a wire nut, we need to make sure the wires have been stripped. We should strip about an inch of insulation from the end of each wire.
Next, we need to hold the exposed end of both wires next to each other. Using pliers, we can twist the exposed end of the wires together.
Insert the twisted wire into the wire nut. Twist the wire nut until it is securely on the wire. These two wires are now connected.
Crimp-on’s are another type of common connector. Crimp-on terminals are also called sta-kons. Crimp-on terminals can connect one or multiple wires together.
Crimp-on terminals can produce reliable and long lasting joints. Crimp-on terminals can also be used to terminate a wire.
Terminating a wire means to connect a wire to a device. For example, you may terminate a wire by connecting it to a relay. The image shows crimp-on’s that have been terminated into a contactor.
To use a crimp-on, we need to select the correct type. Crimp-on connectors come with several different head types. Each head is used to connect to a different component terminal.
Next, you need to strip the end of the wires. Once the wires are stripped, you can insert them into the crimp-on.
Slowly push the wire into the terminal. You should be able to see a small amount of conductor on the opposite side.
Next, you will use a crimping tool on the plastic segment of the crimp-on. Once you have crimped the connector, pull the wire and the crimp-on in opposite directions. You should not be able to pull the wire out of the crimp-on.
A butt splice can also be used to attach two wires together. A butt splice has a plastic sheathing, and a metal connector in the middle. Butt splices are commonly used for lower voltage connections, for example, 24V.
To use a butt splice, start by stripping the ends of two wires. Place the exposed end of one wire into one side of the butt splice. The copper should be pressed against the metal bar in the middle.
Next, use your crimping tool on the center of the butt splice to create a secure connection.
Repeat this process on the opposite side of the butt splice with the other wire.
Gently pull both wires in opposite directions. The wires should not come out of the butt splice.
If the wire comes out of the butt splice, you will need to restart with a new splice. Butt splices can only be used once. In some cases, you will apply heat to a butt splice to create a strong connection.
In this module, you learned about:
Cutting wire,
Stripping wire,
Bending wire, and
Connecting wire
Contactors & Relays
In this module, we will teach you how to:
- Wire components in series,
- Wire components in parallel,
- Wire a contactor, and
- Wire a relay Skip to quiz!
Wiring Series & Parallel Components
Recall that you can wire components in two ways:
Series, and
Parallel
Components in series have one path for current to flow. The current flows from the exit of one component directly to the entrance of the next component.
Let’s look at how to wire components in series. To wire in series, we need to connect a hot wire from the exit of one component to the entrance of the next.
For example, look at the wiring diagram to the right. You can see the wire going from the HPS to the DTS. There is only one path for current. The HPS and DTS are in series.
Components in parallel have more than one path for current to flow. The current flows from the exit of one component and branches into the entrance of multiple components.
Wiring components in parallel is more complicated than wiring in series. To wire components in parallel, we need to combine the wires coming from each component.
For example look at the circuit to the right. The two switches are connected in parallel with each other.
The black wires in this circuit are hot wires. We need to combine the hot wire from the outlet to the two hot wires at the switches. To do this, we combine the three wires with a wire nut.
We also combine the hot wires from the switches to the light bulb. Finally, we combine the ground wires from the outlet and switches. Notice that the switches are now connected in parallel with each other.
Wiring a Contactor
Now that you are familiar with the basics of wiring, we will teach you how to wire several components.
The components we will cover are:
A contactor, and
A relay
Recall that all components have a hot, ground, and neutral wire.
Recall that a contactor is a type of switch used in high voltage circuits. A contactor is a common component in electrical systems.
There are several types of contactors like 1 pole, 2 pole, and 3 pole contactors. In this module, we will be wiring a one pole contactor.
A contactor has 3 parts:
The incoming power terminals,
The exit terminals, and
The 24V terminals
All of these components are labeled in the diagram to the right.
To know where to connect each wire, you will need to refer to the wiring diagram. Wiring diagrams will label each port on the contactor.
For example, you will notice that the wiring diagram labels the contactor “21”. You can find a “21” marking on the contactor.You use this number to know which wire to insert into each port.
To begin wiring the contactor, we need to turn the power off. Before handling any wires, you must use your multimeter to confirm there is 0V in the wire.
Recall that L1 and L2 bring power into the system. The incoming power terminals are ports for L1 and L2 to connect into.
Next, we need to insert the 24V wire into the two terminals. In this case, the 24V comes from the thermostat.
Finally, we need to connect wires into the output terminals. The wires leaving the output terminals will connect to other components.
Let's look at an example of how to wire a contactor. We will use the same wiring diagram that we have been using. The contactor has been highlighted in the image.
We need to start by turning the power off to the circuit. Once the power is off, connect L1 into terminal “11” on the contactor. L2 connects into terminal “23” on the contactor.
Once we have inserted L1 and L2, we need to connect the 24V wires from the thermostat.
Finally, we need to wire the contactor outputs. The wiring diagram shows multiple wires going from terminal “21” to other components. We will use a crimp-on connector to terminate multiple wires.
In the schematic, you can see that wires go from terminal “21” to the SR, COMP, and OFM. To achieve this, we need to insert three wires into the crimp-on that terminates into terminal “21”.
Each of the three wires in the crimp-on will go to a component. We will repeat this process for terminal “23” which connects to the COMP and ST.
Once these connections are complete, the contactor has been wired!
Wiring a Relay
Recall that a relay is another type of switch. Relays can be used with multiple voltage levels.
A relay can have several terminals. This module will focus on a relay with three terminals.
You can see an example in the image to the right.
On a diagram, you can see that each of the relay’s terminals are labeled. Each circle within the relay represents a terminal. Each number next to a circle is the label for the terminal.
In this example, we are looking at a start relay on an HVAC unit. You can see that there are 3 terminals labeled 1,2, and 5. Each terminal of the relay will have one of these numbers.
Always start by turning off the power before handling any wires. Notice that a wire goes from terminal 1 to the start capacitor. The wire should be brown to follow the wiring diagram.
A wire goes from terminal 2 to the H terminal on the dual run capacitor. The wire should be blue to follow the wiring diagram.
A wire also goes from terminal 5 to the “21” terminal on the contactor. The wire should be black to follow the wiring diagram.
To connect each wire to the relay, you will use a crimp-on. Once you connect all three terminals, the relay has been wired!
In this module, you learned how to:
Wire components in series,
Wire components in parallel,
Wire a contactor, and
Wire a relay
Switches, Capacitors and Motors
In this module, we will teach you how to wire a:
- Switch
- Capacitor, and
- Single phase motor Skip to quiz!
Wiring a Switch
A switch is a device used to connect or disconnect the flow of current in a circuit. The light switch in your house is a type of switch.
A switch has three terminals:
A ground terminal, and
Two hot terminals
Each terminal has a screw that can be tightened or loosened.
To wire a switch, we bend the exposed copper wire into a hook shape. The hook shape allows us to attach the wire to a terminal. The hook goes underneath each screw.
To wire the switch, we start by loosening each screw on the switch. Once the screw is loosened, we hook the wire underneath the screw head.
Once the hook is under the screw head, we tighten the screw again. The screw holds the hook in place and makes a strong connection.
We connect the ground wire to the green terminal of the switch. We will connect a hot wire into each of the hot terminals.
One hot wire comes from the previous component in the circuit. The other hot wire goes to the next component in a circuit.
Wiring a Capacitor
Recall that a capacitor is used to store electrical energy within a circuit. Capacitors are rated in farads. For example, you may work on a 5 microfarad capacitor.
You will learn to wire two types of capacitors:
Run capacitors, and
Dual run capacitors.
Run capacitors only have two terminals. Dual run capacitors have three terminals.
To wire a capacitor, we need to connect wires from each terminal to the correct component. For example, you may run a wire from the FAN terminal to the fan motor.
To connect wires to a capacitor, we will use crimp on connectors. Recall that crimp-on connectors have one or more wires with a terminal on the opposite end.
In the diagram to the right, you can see a run capacitor. The run capacitor has two terminals on it.
One wire goes from a terminal on the run capacitor to the COM terminal on a dual run capacitor. You can see this wire highlighted in the schematic.
Another wire goes from the start capacitor to terminal 1 of the start relay. This wire connection has been highlighted in the graphic.
Once these two connections are made, the capacitor has been wired.
Wiring a dual run capacitor is similar to a run capacitor. You can see an example of a dual run capacitor in the image to the right.
Each terminal of the capacitor can connect to multiple components. For example, the HERM terminal has two wires connected to it.
These two wires are connected by a crimp-on terminal. The crimp-on allows multiple wires to connect and terminate into one component. In this case, the wires terminate at the H terminal.
Wiring a Motor
Recall that a motor turns electricity into mechanical energy. A motor can be used to turn a belt, fan, and many other objects.
There are two types of motors:
Single phase, and
Three phase
For this module, we will focus on wiring a single phase motor.
There are many types of motors, but each of them has a:
Start winding,
Run winding, and
Start capacitor
Some motors will also have a run capacitor.
Recall that factory wiring is done by the manufacturer of the product. A motor will have five wires installed by the manufacturer.
The motor will have a:
Ground wire,
Two wires for the run capacitor,
Line wire, and
Common wire
Each of these wires needs to be connected to the correct component. We will reference the wiring diagram to determine the connections.
Let us look at a concrete example. We will walk through wiring the outdoor fan motor (OFM) in an HVAC unit. The OFM has been highlighted in the schematic diagram to the right.
The hot wire goes from terminal 21 of the contactor to the motor. You will use a wire nut to connect the two hot wires. This connection has been highlighted in the diagram.
The neutral wire goes from the OFM to L2. These two wires will be connected with a wire nut.
This connection has been highlighted in the image to the right.
Next, we will connect the brown wire from the motor to the F terminal on the capacitor. We will use a crimp-on connector for this. The connection has been highlighted in the image.
Finally, we must connect the green wire to ground. You can see the ground symbol in the schematic to the right.
The OFM for an HVAC unit has now been wired!
In this module, you learned how to wire a:
Switch
Capacitor, and
Single phase motor
Question #1: To cut wire, you will use:
Linesman pliers
A hammer
Needlenose pliers
A saw
Scroll down for the answer...
Answer: Linesman pliers
To cut wire, you will use linesman pliers. The bottom segment of the jaw cuts through wire.
Question #2: To remove insulation, you will use:
Linesman pliers
Crimpers
Wire strippers
Crescent wrenches
Scroll down for the answer...
Answer: Wire strippers
To remove insulation, you will use wire strippers. Wire strippers have several holes in its jaw. Each hole is used to strip a specific gauge of wire.
Question #3: Which of the following is a wire connector:
Wire nut
Butt Splice
Crimp-On
All of the above
Scroll down for the answer...
Answer: All of the above
Wire nuts, butt splices, and crimp ons are used to connect wires. Crimp ons are also great for terminating wires into a component.
Question #4: To wire components in parallel, you must:
Connect the hot wires of each component
Connect the ground wires of each component
All of the above
Scroll down for the answer...
Answer: All of the above
To wire components in parallel, you will connect the hot wires together with a wire nut. You will also connect the ground wires together with a wire nut.
Question #5: To wire a contactor you must:
Wire the input terminals for L1 and L2
Wire the 24V power from the thermostat
Wire the outgoing terminals
All of the above
Scroll down for the answer...
Answer: All of the above
A contactor has six terminals. Two are for L1 and L2. Two are for the 24V power from a thermostat or other device. Two are for the outgoing terminals. All of them must be wired for a contactor to work.
Question #6: The wiring diagram will you show ___ about a relay:
The label of each terminal
What wire connects into each terminal
All of the above
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Answer: All of the above
The wiring diagram will show you the labels for each terminal. For example, terminals one, two, and five. It will also show you what wires connect into each terminal.
Question #7: A dual run capacitor has ____ terminals:
One
Two
Three
All of the above
Scroll down for the answer...
Answer: Three
A dual run capacitor has three terminals. HERM, COM, and FAN. A run capacitor only has two terminals.
Question #8: A single phase motor comes with what factory wiring:
A hot wire
A neutral wire
A ground wire
Wires for the capacitor
All of the above
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Answer: All of the above
A single phase motor has five factory wires. They are a hot wire, neutral wire, ground wire, and two wires for a capacitor.