In today’s world, most gadgets that you see around are powered by electricity. So, having constant access to electricity is a necessity at this point.
To have a continuous and good power supply all over the house, it’s very important to set up the electrical system properly. For this, while building a new house you must know how many feet of wire are required in that house.
This amount greatly varies depending on the size and layout of the house. The general thumb rule is to use 1 feet of wire for every square foot of the house.
Now, in this article, I’ll be discussing everything you need to know about the wiring of a house. Go through the whole piece for gathering all the information that you need.
Understanding Electrical Wiring in a House
The typical electrical wires of a house come in mainly four different colors- black, white, copper, and red.
The black wire is known as the “hot wire” in a circuit. It carries the current from the switch panel to the electrical appliances.
Although there is no specific NEC requirement that a hot wire has to be black-colored, the black casing usually identifies a wire as live. Other wires like red, blue, or yellow wires can also be used to carry electricity in a power outlet.
White wires are identified as “neutral wires”. After a live wire starts carrying the electricity through the circuit, there must be another wire to carry the unused current back to the breaker panel. White or neutral wires fulfill this role and complete the circuit.
The copper wires are mostly used as the “ground wires”. If current ever takes an unintentional path, they safely deliver it back to the earth’s surface. They work as safety valve and prevent residents from getting electrocuted.
For the appliances that need an additional “hot wire”, three-conductor electrical wires are used. It has an additional red wire along with black, white, and copper wires. This red wire is used as a “second hot wire” in this case.
While working with the wiring of a house, you must always connect two wires of the same colors. Connecting the wrong wires together can damage the entire circuit and create a fire hazard.
Read Also: Does a Subpanel Need a Ground Rod
Factors Affecting the Amount of Wire in a House
The main factor that affects the amount of wire is the size and the number of power outlets in a house. For starters, you should buy 1 ft. of 14-2 electrical wire for each square foot of the house and consider about 25% of that for 14-3 and 12-2 wires.
But keep in mind that these are only for the main building and will not cover any separated structures like a garage or basement. The total wire requirement also changes with the story of the building.
Naturally, a two-storied building would require more wire than a single-storied house to ensure proper access to power. Also the more power outlets and switches your house has, the more wires you will need.
Moreover, which type of wire you are using also affects the total amount of required wire. Usually, buildings that have copper wiring require much fewer amount of wires compared to buildings that use aluminum wiring. So, choose the wiring material wisely depending on your budget.
Calculating the Amount of Wire in a House
The primary estimation of wiring for a house is very simple. You will need an ft. of 14-2 wire for each sq. ft. of the house and 25% of that for 14-3 and 12-2 wires.
The numbering system of a cable has two separate numbers. The first number denotes the conductor’s gauge and the second one defines the number of conductors inside the cable. A 14-2 wire means the wire is 14 gauge and has 2 conductors.
Suppose, your house is 2500 sq. ft. in size, so the standard estimation would be to purchase 2500 ft. of 14-2 and 625 ft. of 14-3 and 12-2 wires. However, this is only the initial estimation. It will keep varying depending on the house’s layout.
The more power outlets and stories a house has, the more wire it will need. So, it’s always better to overestimate a little while purchasing wires.
Tips for Planning Electrical Wiring in a House
While planning the electrical wiring of a house, you must keep the wiring sizes in mind. The most common type of wire you’ll find is the 12 gauge or the 14 gauge wire.
Other than these, there are also 10, 8, and even 6-gauge wires available in the stores. These are mostly used with larger electrical appliances. When you are adding a power outlet, match the new wire’s gauge to the existing wire’s before installing.
Apart from this, there are some other steps that you must follow while planning the electrical wiring in a house:
1. Design a Wiring Diagram
Designing a wiring diagram is the first step of the planning. This design should be detailed and thorough. The diagram should show the exact locations of the power outlets, fixtures, and breaker boxes.
This way you’ll get an idea of how much wire you might need in which place.
2. Disconnect Power
The next step should be turning off the main power supply of the house. This is the most crucial step. No matter how minor a task you are doing, always turn off the power before working with the wiring.
Otherwise, the power can accidentally turn on at any time and create a hazardous situation. Switching it off ensures that you will not get electrocuted while working on the wiring.
3. Set up the Electrical Board
Identify the place where the electricity enters your house from the supplier. Take a screwdriver and hammer and make a hole in that place. This will allow the electrical conduit to enter the house and supply power.
Next, set up an electrical board in that spot. It is a crucial part of the electrical wiring system of a building. The electrical board gathers and distributes the power to all of the appliances and outlets.
4. Understand the Outlet Counts
From the wiring diagram, you must identify the positions of all the power outlets. You should also find out the number of switches required in each room. This will affect the amount of wire needed.
5. Add a Circuit Breaker and Electrical Box
Lastly, you will need to place a circuit breaker and an electric box in your house. The circuit breaker should be placed where it can be accessed easily. So, that in times of emergency, you can turn it off quickly.
Next, connect the electrical box to the service board of the circuit breaker. Place and connect the wires in their designated place and you will be done.
Planning the wiring of an entire house is not an easy task. So, if you are not confident enough, you should take the help of a licensed electrician. Always remember that playing with electricity is not a joke.
So, don’t take any unnecessary risks and seek the help of a professional whenever it is needed. However, if you decide to do it on your own, learn the local building codes first.
Gather knowledge about all the safety information and learn your way around the planning of a building wiring before you take up the job.
Watch this video: Wiring Mistakes Most DIYers Don’t Know
Common Electrical Wiring Mistakes to Avoid
Some of the common electrical wiring mistakes homeowners make are:
- Improper placing/bonding of the ground wire. This will prevent the ground wire from carrying the current safely back to the earth and increase the risk of electrical injuries.
- Not installing a Ground Fault Circuit Interrupter (GFCI) which leads to reducing shock protection.
- Overloading the circuits by connecting multiple appliances in the same circuit.
- Not getting a proper idea of the wires before installing the wiring system. Basic knowledge about the ground, live, and neutral wires are necessary before working on the electrical wiring of the house.
- Installing faulty, loose, or improper wires is also a very common mistake. Many homeowners often connect wires in the wrong conduit which ultimately leads to short-circuiting the entire system.
- Leaving the electrical outlets unsecured. This could potentially end up causing an electrical fire hazard.
Frequently Asked Questions (FAQs)
How Many Feet of Electrical Wiring is Used in a House?
There is no definite answer to this question. It depends on a lot of factors but especially on the size of the house. The more sq. ft. a house has, the more wire it will need.
The standard estimation is 1 ft. of electrical wire for each sq. ft. of the house. However, it also greatly depends on the number of rooms, stories, power outlets, electrical layout, and also wire material.
Other than these, you will also need to calculate the amount of wire needed for the extra spaces such as the garage, basement, or shed separately.
How Deep are Electrical Lines in a House?
Typically, electric lines are buried at least 2 feet under the ground for safety purposes. Although it varies with the local building wiring codes, the bare minimum is to bury them at least 12 inches deep.
This is done to prevent the risk of damage to the cables due to friction, digging, or landscaping work. It will also minimize the risk of the cables getting exposed and electrocuting the residents.
Which Type of Wire is Mostly Used in a House?
N-M cables or Non-Metallic cables are the most common type of wire used for residential buildings. They are also known as the Romex cables. These cables contain 3 or more conductors that are wrapped together with a plastic cover.
In second place comes the Metal-Clad cables or the Armored Cables. These are used when the N-M cables are not enough. These are most suitable in places where the wires can be exposed to possible damage like the basements of your house.
However, Armored Cables can only be used in buildings that have less than 3 stories.
Measuring the amount of wire needed for a specific house is no easy job. It can get quite tricky often. You never know when and where you might need some extra piece of wire. So, while calculating and purchasing, it is always better to overestimate rather than underestimate.
Also, seek professional help whenever you find yourself in a difficult or confusing situation. Remember that, playing with electricity is not something to take lightly. So take proper safety precautions and follow the building codes properly and you should be good to go.