We use electricity every day to charge our phones and tablets, to power our appliances, and to give us light! So, how are we able to use electricity as safely as we do with so few problems? That’s where ground wires come into play!
These little copper wires keep millions of houses and buildings safe from dangerous electrical mishaps.
Without them, the chances of fires and electrical shocks would be much, much higher.
But what does a ground wire do?
Well, I’m so glad you asked, because in this article you’ll learn everything you need to know about them and how to check if your outlets have ground wires.
Let’s get into it!
1. What is a Ground Wire?
A ground wire is a copper wire that is connected to outlets, electrical cords, and circuit breakers.
In the case of a ground fault, which occurs when electricity’s normal flow is obstructed due to wires that are malfunctioning or exposed, the ground wire acts as an alternative route.
Ground wires are a safety measure to ensure electricity doesn’t leak or run through the surface of appliances, preventing people from getting shocked.
They also ensure electricity doesn’t leak onto flammable objects within a house or building, preventing electrical fires.
But where does the ground come into the picture?
Ground wires are also used to protect from surges of electricity.
Breaker panels will have a ground wire that connects to a ground rod placed into the earth.
During an electrical surge, the excess electricity will go down the ground wire to the rod and into the ground, keeping your appliances and house safe.
But how exactly does the process work?
2. How Does a Ground Wire Work?
Electricity runs on a circuit.
That means the electricity flows to the outlets in a home or a building and then flows back to the power sources (referred to as a transformer).
Electricity is brought in by the hot wire and comes back by the neutral wire.
This process works great as long as nothing happens to either of these wires.
But if something does happen, the ground wire is there to save the day.
For example, if you have a minifridge, and its wire becomes exposed and touches the surface of the appliance, the electricity will run across the surface in order to get back to the neutral wire to complete the circuit.
Electricity is attracted to materials that provide the least amount of resistance to travel as quickly as possible, and metal is an excellent conductor of electricity.
The problem is that touching the minifridge would then electrocute you because the electrical current is running through it.
But if there is a ground wire, the electrical current will choose to use it to complete its circuit because copper has an extremely low resistance.
The minifridge would then be safe to touch.
However, because copper is such a great conductor, the electrical current will increase drastically, which will cause the breaker to trip–cutting off power to the outlet.
3. How Does Ground Rod Work?
We can’t fully answer the question of what does a ground wire do without talking about ground rods.
When a house is grounded, it will have a ground wire that is run from the main circuit breaker panel to a rod inserted into the ground.
The ground rod, just like a ground wire, is made of copper.
When the electricity from power surges makes its way down to the rod, it’s then safely discarded into the earth.
4. Does A Ground Wire Have Electricity?
Ground wires do not carry electricity unless there is a ground fault or a power surge.
Unlike hot and neutral wires (the two wires used to bring electricity to an outlet and back to the power source), this wire is not a part of the normal electrical circuit.
It is only used in the case of a mishap, whether it be an exposed or deteriorating wire, or a sudden increase in power.
Even when used, electricity will only run through them for a short amount of time.
The increase of the electrical current should quickly flip the breaker, or the power surge will immediately be redirected down to the ground rod.
5. Is A Ground Wire Necessary?
Having a ground wire is not necessary to obtain electricity from an outlet.
But it is necessary to keep you, your appliances, and your household safe.
So, although it might not be required to operate a device, it is a very important feature to use.
Some devices and applications do require a ground wire, which you can detect if the plug has a bottom D-shaped hole.
Yep, the third prong of a plug is directly related to the ground wire and is not used to harness electricity– you learn something new every day!
6. What Happens if You Touch a Ground Wire?
As long as everything in your home’s electrical system is functioning properly, nothing should happen when you touch the ground wire.
They only carry electricity during a malfunction.
So, touching it in normal circumstances would not result in electrocution.
Do I recommend you give this a try?
Absolutely not!
It can be difficult to fully investigate your electrical system, and if something were to go wrong unexpectedly, you might be in for quite the shock.
If you need to handle any wires that electricity may or may not be running through, the safest method would be to manually flip the breaker. That will shut off power to the source you need to access, and you can be assured that you are safe.
Keep in mind that a poorly installed ground wire could also cause problems, so choose an experienced electrician to do your electrical work.
7. Why Is the Ground Wire Bare?
If you’ve ever looked for the ground wire in your home or an appliance, you may have noticed it’s not insulated.
Well, although sometimes insulated (more on that below), the reason the wire is usually kept bare is to make it as conductive as possible to attract the electrical current.
When there’s an issue with a wire and electricity leaks out, it will then look for a conductor with the least amount of resistance in order to complete its circuit back to the power source (transformer).
Because copper has extremely low resistance levels, electricity will choose it instead of other materials. That is how the ground wire controls electrical currents from spreading to flammable objects and prevents unsuspecting humans or animals from getting shocked.
8. Can You Put Electrical Tape on Ground Wire?
You can put electrical tape on the ground wires.
The great thing about electrical tape is that it has low conductivity, meaning electricity doesn’t like to travel through it.
With that being said, applying electrical tape is by no means necessary.
Even if your ground wire is exposed, it’s nothing to worry about!
It only carries an electrical current if an issue occurs, which, in most cases, would result in the breaker being flipped.
But if you want to apply electrical tape, go for it!
It will help you identify which wires are which and prevent confusion if you need to do any electrical work.
9. Does a Ground Wire Need to Be Green?
A ground wire comes with a few rules.
A majority of ground wires are bare, but if the wire is going to be insulated, it has to be green or yellow.
That means you cannot fully wrap black electrical tape around the wire.
I’m not just making that up.
The rule comes from the National Electrical Code (NEC)!
Unless you are installing a ground wire yourself, you really don’t need to worry about it.
All reputable electricians will follow the necessary codes.
If they don’t, well, they’ll go out of business faster than a ground wire flips a breaker–did you enjoy that electricity joke?
10. Can a Ground Wire Cause a Fire?
If you asked an electrician what does a ground wire do, they would say it helps prevent electrical fires.
But can it cause a fire?
It’s unlikely, but yes, it is possible that a ground wire could cause a fire.
But before you categorize it as a double-edged sword, let’s talk about why this would happen.
A ground wire that is not properly installed could lead to increased heat (resistance) and result in a fire. Furthermore, if it were to make contact with another electrical source, it could cause sparks, resulting in a fire.
But don’t let that scare you.
Its purpose is to prevent fires; it’s highly unlikely that they would be the cause of one.
If you were to uninstall the ground wires from your home, the chances of an electrical fire would be much higher.
So, just make sure the person doing the wiring in your home is experienced and follows all codes.
11. Can A Ground Wire Touch Other Wires?
Ground wires touching exposed hot and neutral wires could lead to problems. But if they only touch properly insulated wires, it’s nothing to worry about.
Because a ground wire has such low resistance, touching it to other exposed wires could disrupt the flow of power.
It can touch another ground wire–the electricity would be able to complete its circuit safely.
If you are ever uncertain about your home’s electrical setup, call in an electrician to verify everything looks correct.
12. How Do I Know If My Ground Wire is Working?
To check if your ground wires are working, you first need to identify that your outlets have them.
You can verify this if it is a three-prong outlet.
If it has slots for three prongs, it has a ground wire; if it has two, it doesn’t.
Now let’s go through the steps to test your outlets, including the hot, neutral, and ground wires (you will need a multimeter to do this).
First, insert the red lead into the right slot (the smaller slot) and insert the black lead into the left slot (the bigger slot).
The device should show a reading between 110 to 120 volts, indicating a properly functioning outlet.
To check the ground wire, keep the red lead inserted and remove the black lead.
Insert the black lead into the bottom D-shaped slot.
The device should again show a reading between 110 to 120 volts, indicating a properly functioning ground wire.
If the reading from your test is outside of the 110 to 120 range, contact an electrician to diagnose the issue.
Electrical problems can be dangerous, so don’t wait!
13. What Happens if a House Isn’t Grounded?
A house that isn’t grounded is vulnerable.
It’s possible that an ungrounded house will never run into any problems, but it’s a roll of the dice.
If your house or power source is struck by lightning, a power surge could damage appliances plugged into sockets or cause electrical fires.
An ungrounded house will also be threatened by damaged or deteriorating wires that cause the electrical currents to find new routes, which could lead to electrocution or fires.
A ground wire is the best protection against electrical emergencies, and although it’s unlikely for serious issues to occur, they can happen, and it’s best to be prepared.
The good news is that houses in the United States are required to be grounded.
So, unless you live in a house older than 80 years with out-of-date electrical work, you should be in the clear.
14. What Appliances Need to Be Grounded?
Not every appliance needs to be grounded.
Now that we know that appliances with a three-prong plug mean it has a ground wire, what does that mean for appliances that only have a two-prong plug?
When an appliance only has a two-prong plug, that indicates it was designed in a way to prevent users from getting shocked.
The latest appliances now use double insulated cords, which give the wires a second layer of protection.
Even if the primary layer of insulation wears down, the wire will still not be exposed, preventing electricity from leaking out.
Let’s take a look at appliances that commonly have a ground wire and those that don’t.
Appliances That Have One
TV’s
Computers
Power tools
Outdoor equipment
Washers and dyers
Other high-end appliances
Appliances That Don’t
Lamps
Kitchen appliances (blenders, coffee makers, etc.)
Phone chargers
Vacuum cleaners
Bathroom appliances
Final Thoughts
The next time you’re at a dinner party and someone asks what does a ground wire do, oh, you will be ready to give them quite the answer!
A ground wire is a wonderful safety tool that has been preventing fires and damage to appliances for decades.
It’s important to ensure your home is properly grounded to keep yourself and your family safe from real danger caused by electricity.
So, test your outlets and have an electrician do an overall inspection; you’ll thank yourself later!
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Disclaimer: we are not lawyers, accountants or financial advisors and the information in this article is for informational purposes only. This article is based on our own research and experience and we do our best to keep it accurate and up-to-date, but it may contain errors. Please be sure to consult a legal or financial professional before making any investment decisions.
Prior to starting Gokce Capital, Erika received a Bachelor of Architecture from the University of Southern California and a graduate degree in Urban Policy from Columbia University. She worked as both an architectural designer and engineer in New York before joining the New York City Department of Housing Preservation and Development.
Erika currently lives in the New York Metropolitan area with her spouse, daughter and cat. She is originally from Chicago and still considers herself a midwesterner at heart.
Erika also loves to read, write and travel (fun fact, she has visited all 50 states and more than 30 countries!). Her new book, Land Investing Mistakes: 11 True Stories You Need To Know Before Buying Land, is now available on Amazon.