Basic Wiring : Chapter 1
Wire Types
In this module, we will introduce you to wires. We will cover:
How wires work, and Types of wires you will see in the field. Skip to quiz!
Overview
Recall that a circuit works by pulling current from a power source. As the electrons move from the power source to a load, like a lightbulb, the load receives power.
Wires connect together each component in a circuit. Wires give electrons a path to move from the power source to components.
You can think of a wire as a road for electricity. We use a road to move from place to place.
A wire is used to move electrons from place to place.
Recall that a wire has two components:
A conductive inside, and
An insulating sheath
The conductive inside allows electrons to move through the wire with low resistance. The insulating sheath is non-conductive. It prevents current from moving between two touching wires.
Hot, Ground & Neutral Wires
We describe wires as a:
Hot wire,
Neutral wire, and
Ground wire
The terms hot, ground, and neutral explain what the wire is doing in a circuit. Hot, ground, and neutral wires have a conductor and non-conductive insulation.
The hot wire carries electricity into a component. Typically, the hot wire will be black or red.
In the image to the right, the hot wire is highlighted. The hot wire is carrying electricity from the battery to the light bulb.
There can be multiple hot wires in an electrical system. The hot wire carries power to each component in the system.
The hot wires are highlighted in the circuit to the right. There is a hot wire from the outlet to the switches. There is another hot wire from the switches to the light bulb.
The neutral wire connects the last component in a circuit back to the power source. The neutral wire creates a complete path for the current to flow. A neutral wire usually has white insulation.
The neutral wire has been highlighted. The neutral wire runs from the exit of the light bulb to the power outlet.
Unlike a hot wire, there is only one neutral wire in a system. It goes from the last component of the circuit back to the power source.
To recap, the hot wire carries electricity into a component. The neutral wire returns electricity from the last component to the power source.
Recall that circuits have a ground wire. Recall that there are two types of voltage, AC and DC.
The ground wire works different on an AC and DC circuit.
A short circuit is an unintended, low resistance, path for current to flow. A short circuit can cause the metal parts of a component to become charged. A short circuit can shock you or damage components.
A short circuit can shock you or damage components. Short circuits can happen in AC and DC circuits. The ground wire is designed to protect the system from short circuits.
For an AC circuit, the ground wire connects the circuit to the earth. It reduces the chance of you being shocked. It also protects components from being damaged.
The ground wire has a very low resistance, which draws a lot of current. When a short circuit happens, the current will flow through the ground wire.
The excess current goes deep into the ground where no one will be harmed. The excess current will also trip a breaker or fuse that removes power to the circuit.
In a DC circuit, the ground wire does not connect the circuit to the earth. The ground wire in a DC circuit acts as a 0V reference for the system.
The ground wire in a DC circuit is called a “floating” ground. The ground wire acts as a return path for current to the negative terminal of the power supply.
Wire Sizes
All wires come in a variety of thicknesses. We measure the thickness of a wire by “gauges”.
For example, you may see a 10 gauge wire.
The lower the gauge, the thicker the wire is. For example, a 4 gauge wire will be much thicker than a 10 gauge wire.
A gauge tool is used to measure wire size. A gauge tool has slots around the entire circle. You determine the wire size by placing the conductive part of the wire in a slot.
The amperage rating is the maximum amount of current the wire can carry without overheating. The larger the wire, the higher the amperage rating.
The more power a component needs, the larger the wire you will need to use. For example, a low voltage light may only use an 18 gauge wire. An air conditioner may use a 10 gauge wire.
In the chart to the right, you can see the maximum amperage of several types of wires. Always use a wire that can handle the current in the system. If a wire receives too much current, it will melt or cause a fire.
The specific component you are working on will have a maximum current rating. You can find the maximum current rating in the component manual.
You must choose a wire that can handle the expected current load. Using too large of a wire can cause too much current to flow and damage the component. Using too small of a wire reduces the voltage the component will receive.
Wire Types
There are also several types of wire, including:
Romex,
BX cable,
MC cable, and
UF cable
Romex wiring is commonly used in residential wiring. Romex has plastic insulation around the conductor. Romex is also called NM Wire in the field.
BX Cable Wire is another common type of wire. BX Cable has a metallic sheathing around the conductor. BX cable is used to connect garbage disposals or equipment that vibrates a lot.
MC cable is another type of wire with a metal insulation. MC stands for metal clad. The metal insulation is resistant to corrosion. The metal will not rust in damp and wet places.
UF cable stands for underground feeder cables. They are sunlight and moisture resistant. UF cables are great for burying underground or using outside.
In this module, you learned what a wire is and how to select the correct wire size. You also learned about common types of wiring like Romex, BX cable, and MC cable.
Wire Materials
In this module, we will introduce you to common wire materials.Skip to quiz!
Overview
Recall that there are several types of wire, including:
Romex,
BX cable,
MC cable, and
NM wire
All types of wire are made up of different materials.
A wire can have different:
Conducting material, and
Insulating material
We will cover common types of conducting and insulating materials. Note that there are even more materials than what we will cover.
Conducting Materials
Recall that conductors are a material that allows electrons to move freely from one atom to another. The movement of electrons creates what we know as electricity.
Electrons can freely move in a conductor since the conductor has a very low resistance. Recall that resistance measures a material's opposition to current flow.
Some common types of metal conductors are:
Copper,
Aluminum,
Gold, and
Silver
For wiring, we only use copper and silver.
The most common conductor is copper. Almost all wires use copper as a conductor. Copper is good for wiring since it is cheap to make.
Another common conductor is silver. Silver is not used in wiring since it is much more expensive than copper. You may find silver in small spots on relays or contactors.
Insulating Materials
Recall that insulation is a covering that goes around a conductor. The insulation protects you and the equipment from the charge on the conductor.
Insulators have a very high resistance. The high resistance prevents current from passing through the insulator. Electrical wires are almost always covered with an insulator.
There are several types of insulators that are used with wires.
For example, you may see insulators made of:
Plastic,
Rubber, and
PVC
Insulation prevents the conductors of wires from touching. If two conductors unintentionally touch, then you create a short circuit. Short circuits can damage electrical equipment.
The insulation also protects you from electrical shock. If you accidentally touch a live wire, the insulation will prevent the electricity from flowing into you.
In this module, you learned about common types of insulators and conductors. Conductors allow us to carry electricity through materials. Insulators prevent current from flowing.
Question #1: Wires have two parts. A conductive inside and an insulating sheath.
True
False
Scroll down for the answer...
Answer: True
True, a wire has a conductive inside and an insulating sheath around the conductor.
Question #2: The hot wire in a circuit
Carries power between components
Returns power to the source
Connects power to the ground
All of the above
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Answer: Carries power between components
The hot wire carries electricity to each component.
Question #3: The neutral wire
Carries power between components
Returns power to the source
Connects power to the ground
All of the above
Scroll down for the answer...
Answer: Returns power to the source
The neutral wire is the last wire in a circuit. It returns electricity back to the source. For example, a battery.
Question #4: A 4 gauge wire is smaller than a 12 gauge wire.
True
False
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Answer: False
Electricity causes speakers to vibrate so that they make sound.
Question #5: Most wiring will use a ____ conductor:
Plastic
Cotton
Copper
All of the above
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Answer: Copper
Most conductors are made of metal. Copper is the most common type of conductive material.
Question #6: Why are wires insulated?
To prevent conductors from touching
To protect you from shock
All of the above
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Answer: All of the above
Wire insulation is used for all of these purposes. It helps to prevent conductors from touching, protect you from shock, and protect the conductor.
Question #7: What is insulation usually made up of:
Plastic
Rubber
PVC
All of the above
Scroll down for the answer...
Answer: All of the above
Plastic, rubber, and PVC are common materials for insulating wires.