Everything You Need To Know About Home Electrical Wiring

Ian Mutuli
Updated on
Ian Mutuli

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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People depend on electricity, but understanding its operation can be difficult. A problem with your electrical supply can be confusing and not easy to fix, with professional assistance not being available right away. Knowing the basics of electricity and some of the terms associated with electrical work comes in handy in such moments.

Whether you need to update your switches or are replacing your home transformers, having the proper knowledge will help you finish the job safely. Let’s take a closer look at what you need to know about home electrical wiring. 

What’s Involved in Home Electrical Wiring?

i. Wiring Types

Wiring Types

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It can be overwhelming when you open up your electrical panel and are faced with a tangle of various colored wires. In the light switches, you will find two or more wires. Knowing what each wire is for is the first step to understanding your electrical problem.

1) Black Wires 

    • Due to their electrical conductivity, they are known as “hot wires.” There is no switch to turn them off, so they always remain on. A black wire carries high voltage and little current.

2) Yellow Wires

    • Heavy appliances such as stoves and ovens use blue and yellow wires. A minimum amount of electricity is required to power these appliances, which is more than the electricity needed to power lights.

    • Sometimes the yellow wire can be used instead of green wire and sometimes as the live wire depending on the building or national code.

3) Green Wires

    • The grounding terminal on the outlet box is connected to these wires to ensure electricity does not pass through you during an electrical malfunction by providing an alternate path. The new destination is typically the concrete outside your home.

4) White Wires

    • This is the neutral wire, and electricity is sent back to the breaker panel through these wires.

    • TAKE NOTE: A white wire wrapped in red or black electrical tape is a hot wire.

5) Red Wires

    • Just like the black wires, the red ones are hot wires.

6) Bare Copper

    • A grounding wire is usually made from bare copper.

ii. Connections and Meters

Connections And Meters

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Residential panel electrical wiring begins with the connection point. Meters measure the monthly electricity consumption of your household and communicate this information to the power company. Electricity is distributed throughout the house by the electrical panel.

To control electricity in your home, there is a circuit breaker near the meter. Black wires run underground from your meter to your neighbor. This electrical wire also powers your home. Service entrance conductors are large copper bars connecting to your house’s panel. 

iii. Circuit Breaker Panel

Circuit Breaker Panel

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Circuit breakers connect all of the electrical wires in your home. Every breaker on the main service panel controls a different electrical circuit; between 100 and 200 breakers are usually located there. Load and line service panels are the two main types. Wires connect to the panel on the load side, while power lines enter the house on the line side. Any electrical system work should be performed on the load side. Before you begin working on these panels, you should turn off the power from the panels to the meter.

iv. Electrical Boxes

Electrical Boxes

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Most homes have plastic or metal electrical boxes. A house’s electrical system typically has many breakers and fuses that trip if the voltage is too high, as well as the various rooms’ wiring. A junction box should be in each room of the house. Color-coded wires run to these boxes. A 3-way switch will require two more white wires to come out of this junction box. 

v. Switches


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Devices are powered on or off by switches. An outdoor breaker box is usually located near the entrance to the house, or an indoor breaker box can be found near the door. Switches are often controlled manually with screws. When mounted on a wall, most switches also include an electrical box. The wires of the power lines connect directly to the lugs on the switch in such cases. Outlets and switches both come in 15- and 20-amp versions. A small triangle next to the switch number indicates an amperage load.

vi. Outlets


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The electrical outlets that supply power to your home’s appliances and devices are called receptacles. Understanding how an outlet is wired is essential. There are two types of home outlets: 15-amp and 20-amp. A 15-amp outlet has a different color code than a 20-amp outlet.

In the middle of an ordinary home outlet, there are two horizontal and two vertical slots. Wide blade plugs can be accommodated in the left slot, which is wider than the other two slots. Under the right side slot, there is a round hole for grounding but no cut-out in the middle. In some outlets, you can plug in a load up to 15 amps, while others are designed for loads up to 20 amps.

If you have no home electrical experience, it’s crucial that you learn the basics before doing your own electrical work. If you are nervous about attempting simple electrical tasks, it’s always best to bring in a professional electrician. 

vii. Local Building Codes

Local Building Codes

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There are different buildings with different wiring circuits that you need to know about before making any changes. Furthermore, knowing about the national electrical code is even better, as that is the first thing you need to know about.

Consult your building manager if you are in an apartment or your local electrician to know if there is any underground feeder cable or any connection you might not know about.

Frequently Asked Questions About Home Electrical Wiring

Frequently Asked Questions About Home Electrical Wiring

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a) What type of wiring is used at home?

The standard for residential and household wiring is the Romex, which is an electrical conductor with a non-metallic sheathing. The wiring is also known as NM cable, where NM stands for non-metallic. Romex is just a brand that is commonly used and has become synonymous with the NM cable.

When shopping for the NM cable, you will find the NMB cable, which is an NM cable rated at 90 degrees Celsius (194 degrees Fahrenheit).

b) Is house wiring AC or DC?

House wiring is AC. After all, AC can be transmitted over long distances, making it more convenient to use in households over DC. AC can also be stepped up or down to a lower current using a transformer, making the current safer for appliances in the house. Hence, the outlets in the house are always AC.

Anything in your house that is powered uses AC, whether is the screen, the dishwasher, or the fridge.

Here is a tip; if you are moving to a different country with a gadget, ensure you know how many volts it uses, as some countries have different standards for transformers stepping down the AC. For instance, in the US, the mains are 120V, while in the UK, it is 240V. If you are moving to the UK from the US, you would need a step-down transformer to lower the AC for your 120V appliances to avoid “frying them.” If you are wondering why your phone is always fine when you move between countries, it is because the charger is basically a step-down transformer.

c) What are the three types of wires?

The three wires are hot, neutral, and ground wires. The wires are identified by different colors.

    • Black- Hot wires

    • Red- Hot wires

    • Blue- Neutral wires

    • Green- Earth wire

d) Are household wires stranded or solid?

Household wires can either be stranded or solid. You will get a bare copper wire, an aluminum wiring option, or a copper-sheathed aluminum wiring, with the sheathed options being stranded and bare wires being solid.

e) Why is the copper ground wire bare?

Having a bare copper ground wire makes it more effective compared to having wire insulation over it. A bare wire is mostly used on ground wires, as using them on neutral or hot wires might be potentially hazardous. Additionally, having wires other than the ground stay bare goes against the National Electrical Code.

f) What mm wires are required for home wiring?

Electrical wires have different sizes and purposes. For instance, the hot wire does not have a similar cross-sectional area as the earth wire, and so on. The hot wires serving different purposes also have different cross-sectional areas. Here are the sizes and the different purposes they serve;

    • 6 sq. mm- Air conditioners

    • 4 sq. mm- Electrical induction stoves, heaters, geysers, and any appliance requiring 15 Amp

    • 2.5 sq. mm- Distribution Board to mainboards

    • 1.5 sq. mm- Switch box to light fixtures or fan points

    • 1 sq. mm- Earthing

g) Which is more dangerous between AC and DC?

AC is more dangerous than DCand causes more severe muscle contractions if you touch it. Furthermore, the current causes sweating, which worsens the situation.
Note that a DC can also cause a harmful shock. So, take all precautions when working on an electrical project or interacting with an electrical cable in a light fixture or anywhere else.

h) What happens when there is no ground wire?

Appliances can operate normally without the ground wire. The ground wire and ground fault circuit interrupters are meant to protect you and your appliances in case of any power surges.

Final Thoughts

Final Thoughts

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You interact with the home electrical wiring more than you notice, from the light switch to your phone charger, and it is good to know just enough about electricity to be appropriate when handling appliances. Furthermore, simple information can save you an appliance or, better yet, a life.

Ian Mutuli

About the author

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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