Colors And Letters Of Electrical Wiring
All About Electrical Wiring Types, Sizes, and Installation
Much of what you need to know for electrical repairs and remodeling involves wiring—how to identify it, how to buy it, and how to install it with proper connections. If you’re planning any electrical project, learning the basics of wiring materials and installation is the best place to start. Understanding basic wiring terminology and identifying the most common types of wire and cable will help when investigating wiring problems and when choosing the wiring for new installation and remodeling projects.
Understanding Wire Sizing
The proper wire size is critical to any electrical wire installation. Wire sizing indicates the diameter of the metal conductor of the wire and is based on the American Wire Gauge (AWG) system. The gauge of a wire relates to the wire’s current-carrying capacity, or how much amperage the wire can safely handle. When choosing the right size of the wire, you must consider the gauge of the wire, the wire capacity, and what the wire will be used for.
Non-Metallic (NM) Sheathed Cable
Most interior wiring is done with non-metallic, or NM, cable—also known by the popular brand name “Romex.” NM cable is made of three or more wires wrapped inside a flexible plastic jacket, or sheathing. It is used for most interior circuits, such as those for outlets, switches, light fixtures, and appliances. Learn the basics of NM cable to choose the right type for your next electrical project.
Electrical Wire Color Coding
Color coding is used both on the outer sheathing of bundled electrical cables and on the individual conduction wires within cables or inside conduit. Understanding this color coding can help you identify what the wiring is used for and helps maintain consistency within an electrical system.
Understanding Electrical Wiring Labeling
Electrical wires and cable have markings stamped or printed on their insulation or outer sheathing. These markings provide important information about the wiring and insulation, including the wire size and material, the type of insulation, the number of wires contained (inside a cable), and any special ratings or characteristics of the wire.
How to Choose Electrical Wires and Insulation
Resources and description
In this video you will learn about the different kinds of insulation and conductors, and how to choose your own.
The different steps of this short tutorial will show you how to choose the right conductor size, how to determine the conductor’s core and then how to choose the insulation. By learning these three elements, you’ll be able to choose the right conductors and insulation for yourself!
Electrical Wire and Cable Buying Guide
First, understand the difference between wire and cable:
A wire is one conductor that carries an electrical current through a circuit.
A cable is a collection of wires sheathed together.
The American Wire Gauge (AWG) system provides the sizing of wires. The higher the number of the gauge, the smaller the size of the wires. The National Electrical Code (NEC) mandates the regulations for wires and cables that can be used for electrical applications.
Warning
Follow the manufacturer’s instructions for installation and safety. Check to see if you need a permit. Observe applicable building and electrical codes. Contact a licensed electrician if you have any doubts or questions about the connections or if your home’s wiring doesn’t appear compatible with the changes you’re making.
How to Identify Wires and Cables
Each jacket will have information printed on it to help you choose the correct product for your job. A letter code provides the attributes of the wire, along with material, gauge and voltage rating.
Naming and Taxonomy
The NEC provides a system with letters to quickly identify what a wire’s capabilities are. Some common lettering for wire includes THHN, XHHW, THW, etc.
ELECTRICAL TECHNOLOGY
How to Find The Suitable Size of Cable & Wire for Electrical Wiring Installation?
Whenever current flows through a conductor, a voltage drop occurs in that conductor. Generally, voltage drop may neglect for small length of conductors but in case of a lower diameter and long length conductors, we have to take into account the considerable voltage drops for proper wiring installation and future load managment.
In electrical wiring circuits, voltage drops also occur from the distribution board to the different sub circuit and final sub circuits, but for sub circuits and final sub circuits, the value of voltage drop should be half of that allowable voltage drops (i.e. 2.75V of 5.5V as calculated above)
Normally, Voltage drop in tables is described in Ampere per meter (A/m) e.g. what would be the voltage drop in a one meter cable which carrying one Ampere current? There are two methods to define the voltage drop in a cable which we will discuses below.
To find voltage drop in a cable, follow the simple steps given below.
First of all, find the maximum allowable voltage drop
Now, Find load current
Now, according to load current, select a proper cable (which current rating should be nearest to the calculated load current) from table 1
From Table 1, find the voltage drop in meter or 100 feet (what system you prefer) according its rated current
Wire Types and Sizing
When wiring a house, there are many types wire to choose from, some copper, others aluminum, some rated for outdoors, others indoors. In general however, there are only a couple varieties used for wiring a residential home.
Romex Cables
Romex (shown in yellow above) is the trade name for a type of electrical conductor with non-metallic sheathing that is commonly used as residential branch wiring. In fact, Romex will be the most common cable you’ll use in wiring a house
The following are a few basic facts about Romex wiring:
Romex ™ is a common type of residential wiring that is categorized by the National Electrical Code (NEC) as underground feeder (UF) or non-metallic sheathed cable (NM and NMC).
NM and NMC conductors are composed of two or more insulated conductors contained in a non-metallic sheath. The coating on NMC cable is non-conducting, flame-resistant and moisture-resistant. Unlike other cables commonly found in homes, they are permitted in damp environments, such as basements.
Underground feeder conductors appear similar to NM and NMC cables except that UF cables contain a solid plastic core and cannot be “rolled” between fingers.
The following NEC regulations apply to Romex conductors:
They must be protected, secured and clamped to device boxes, junction boxes and fixtures.
Support devices that may damage the cables, such as bent nails and overdriven staples, are not permitted.
NM and NMC cables should be secured at intervals that do not exceed 4½ feet, and they should be secured within 12 inches of junction boxes and panels to which they are attached. Cables that do not comply with this rule can sag and are vulnerable to damage.
They are intended as permanent wiring in homes and should not be used as a substitute for appliance wiring or extension cords.
Romex is used for most lighting and outlet circuits in your home. Romex will be labeled with “12-2” or “12-3”. The first number indicates the gauge of the wire. You choices are typically 10, 12, or 14 gauge. The second number indicates the number of conductors. A 12-2 Romex will have a black(hot) and a white(neutral) wire as well as an unsheathed copper wire for ground. A 12-3 Romex will have a black(hot), red(hot), white(neutral), and bare copper. The red on a 12-3 is used for three-way light switches which are covered later