Electrical Wire And Cable And Its Types
Electrical wires are conducting wires that allow the flow of electricity through them from the power source to end user device or an outlet like switch, fan, etc.
Wires are classified into three different styles. A bare wire comes without any insulated coating, just as the name suggests. Insulated solid wires have a coating of plastic which makes the upper layer insulated. The third category is insulated standard wire.
Insulated standard wire consists of many smaller sized strands of copper and comes in protective plastic coating. It is also known as Type NM cable and is sold with standard lengths of 50′, 100′, 250′, and 1,000′ spools.
Nonmetallic sheathed cable and armored cable are the two most commonly used cable. Nonmetallic sheathed cable consists of two or more insulated conductors and a bare ground wire. All these wires are together wrapped in outer plastic coating which acts as a protective sheet. The armored cable consists of four insulated wires red, white, black and green which are covered with a flexible metal case which is known as cord. Armored cables are cut of fixed size generally but they are also available in precept length roll.
Nonmetallic sheathed cables (NM) that are used for wiring houses come with color coding. The outer cover denotes the amperage rating of the wires inside. Most of the NM wires made after 2001 are covered with distinct coloured coating which makes the identification of these wires easier for both inspectors and consumers.
The color coding of the external sheath is totally dependent on the manufacturers though most of the manufacturers follow the color coding for their wires.
- The Five Basic Colors of Nonmetallic Cable
All household wires are divided into 5 colours for distinction. These colours are gray, white, orange, yellow and black. The color black is used twice for wires with different gauges. Hence you must be aware while selecting the required wire size.
These distinct colors are basic differentiators of the wire covers that are coated above the insulated and non insulated wires.
- White-colored Nonmetallic Sheathed Cable
White color coded wire sheath consists of 14-gauges wire. These wires are ideal for 15-amp circuits in our home. They are primarily used in lighting circuits.
- Yellow-colored Nonmetallic Sheathed Cable
Yellow colour coded wire sheath consists of 12-gauge wire which can be applied in circuits with 20-amp rating. They are generally used for general power for outlets and appliances.
- Orange-colored Nonmetallic Sheathed Cable
Orange color coded wire sheath has 10-gauges wire and is able to withstand 30-amp circuit loads. It is ideal for air-conditioners, water heaters and other appliances with 30-amp load.
- Black-colored Nonmetallic Sheathed Cable
Black color coded wire sheath houses 6 and 8-gauge wires. 8-gauge wires can withstand 45-amp load whereas 6-gauges is ideal for 60-amp load. 6-gauges wires are ideal for an electric range, double oven, or feeding sub panel and depend on the amperage rating listed on the appliance being used.
- Gray-colored Nonmetallic Sheathed Cable
Gray color coded NM wire is more about the area where it is installed rather than the size of its wire. Its application consists of underground installation and is available in varying sizes. Its properties includes water resistance and are also sometimes resistant to oil and sunlight.
- Nonmetallic Sheathed Cable’s Outer Jacket Labeling
All NM sheathed cables have their outer jacket labelled with letters that indicates the number of insulated wires present within the sheath. This wire does not have the count but consists of non insulated wire which is used as ground wire. If a cable has a listing 12-2 WG, then it means that there are two insulated 12-gauge wires and a ground wire. If the cable has 12-3 label, then it means that it has 3 12-gauge conductors along with a bare copper ground wire.