What is the Ground Wire?

Harriette Halepis

A ground wire, sometimes also referred to as a “grounded” wire, is an electrical wire that neutralizes and protects devices, appliances, and buildings from current problems and shocks. Originally the term applied only to wires that were actually connected to the Earth, and in many cases this is still true. Electricity running to homes and office buildings almost always has this in-ground feature. The phrasing has become pervasive, however, and is often used in contexts where there is no actual contact with the literal ground. Cell phones, for instance, may be said to have ground wiring; many small appliances also have wires with this name. In these cases the “grounding” that is happening is really mostly about stabilization.

In many cases, the ground wire is connected in the circuit box.
In many cases, the ground wire is connected in the circuit box.

Importance of Neutrality

Electrical conductivity is somewhat complex, but in almost all cases signals are carried across at least three wires. One is considered hot, one neutral, and one grounded. Hot wires carry signals to something, while neutral ones carry it away. Neutrality is really important here because electricity can’t just run to something in an unchecked way; if it did, it could cause shocks, sparks, and fires. Devices, appliances, and fixtures need to get just enough current to perform their function. Once that threshold is met, the current needs an outlet, which is normally the role of the neutral wire.

In addition to a hot and neutral, most wiring also has a ground wire.
In addition to a hot and neutral, most wiring also has a ground wire.

Ground wires are, essentially, a type of insurance. When a neutral wire does not function, the grounded aspect will ensure that an appliance does not give off a dangerous electrical shock. In homes this wire usually works alongside circuit breakers to prevent electrical fires and other dangers. Most of the time they’re silent or still, but when needed they play an essential role.

In Buildings

Most modern homes and buildings are built with an expansive inner electrical circuitry that feeds outlets and wall sockets. Most of the conductivity happens within the walls or under the floorboards, but usually all connects back to a central circuit breaker that, in most cases, is actually grounded to the physical Earth beneath the structure. Most electricity comes up out of the ground as it is, and the Earth is widely believed to have a stabilizing, essentially constant current.

Red and black wires are usually hot, while white wires are neutral. Grounded wires may connect to sockets in homes and buildings, but not always. When they do they’re often green or yellow. When a white wire is broken, stray current is no longer carried away from the socket and, by extension, whatever is plugged into it. The same thing happens when outlets are overloaded. In both of these cases neutralization is not possible unless there’s a ground wire. It is this wire that will assume the deflected charge and trip the corresponding circuit breaker, stopping any electrical current.

In Appliances

Appliances will operate normally without the help of ground wires, though most will nonetheless include them. In fact, if one is broken or missing, most people will not be able to tell the difference. If a large amount of high voltage has come in contact with the appliance, however, users may get a hefty electrical shock.

The term “ground wire” has become somewhat standard, even for devices that don’t stay plugged in to operate. Mobile phones are one example. It’s common for electricians and engineers to name one of the wires in a phone’s internal circuitry as the “grounded” wire, mostly by analogy. This wire works the same way and has the same function as one actually connected to the Earth — namely, to neutralize currents in case of fault or overload and to provide a return path for unneeded charge — but it is usually sourced a bit differently.

Dangers and Precautions

These sorts of wires aren’t normally dangerous when they aren’t being used, but since they are volatile or “live” when they’re carrying a current it’s best to use caution when handling them. People who are working with electrical wires, whether installing or repairing, usually have to be very careful to identify everything before rearranging or snipping. It is usually very difficult to know if the backup wire is actually carrying a current just by looking at it, which makes erring on the side of caution the best bet in most cases.

There are also a few important things for people to keep in mind when buying a home. Most experts say it’s crucial for buyers to ask a home inspector or electrician to inspect a home's electrical network, paying special attention to circuit breaker boxes and grounded wires. While some homes may appear to be in good condition, faulty wiring can lead to shock and fires. Nearly every country has an electrical standard that includes electrical grounding that all homeowners must adhere to, and these rules exist in order to prevent fires and other dangerous incidents.

Circuit breaker boxes and ground wires work together to protect appliances and the home.
Circuit breaker boxes and ground wires work together to protect appliances and the home.

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Discussion Comments


The way that the nerves are in your palms work is that they contract when an electrical current is touched. Meanwhile, the backs of your palms, when touching electricity, will push away your hand from the current due to the nervous system of the body, so you should always ensure that your palms are up when reaching an electrical enclosure.


I have a dimmable uplighter floor lamp with a missing plug. When I went to rewire it (in the UK) to a new plug, I found a brown wire, a blue wire and a yellow wire (not green and yellow which would normally be the ground in the UK). Can someone help me with rewiring this plug? Because the casing of the lamp is metal, obviously it is important that I get the grounding wire right before I switch it on, or it will be my eyes that light up instead!


Why should you reach into an electrical enclosure with your palm up?


Do ground wires hooked to electrical poles need to be marked? I see some with yellow coating but some are not and are very hard to see.


No you would not get shocked if you touched the ground wire as long as the neutral was still drawing away from the device.


@GlassAxe- I am not a professional electrician so I may not be accounting for all variables, but you can be shocked by either prong in a normal 110V AC plug if you touch the bare metal and it is seated in the socket. Your body is not isolated form the ground, so you become the path for the current to reach the ground. If you were insulated from the ground, which is possible, and you were only touching one prong, you would not be shocked. It would be the same idea as a bird on a wire. That being said, I cannot tell you which prong will shock you since the outlet is an alternating current. There is no dedicated hot or neutral wire if I am correct (I could very well be wrong because I am not an electrician).

I also know that you can be shocked if you are plugging in the device and your hand slips, touching the ground and one of the lead connectors. At this point, you are connecting the alternating hot prong to the ground, completing the circuit to the ground. I hope this explanation of a ground wire connection all made sense. In essence, you could have touched just one prong, two prongs, or a prong and the ground prong. It has happened to me before and it feels like a kick in the arm.


What a straightforward, informative article on ground wires. I am not that knowledgeable about electricity and the inner workings of my gadgets, but this explains the idea in simple terms.

I do have a question though. What happens if I touch a ground wire while an item is plugged in? I once got a painful shock from a television I was unplugging from the wall. I do not know which prong is which, but I touched one (maybe more) of the prongs as I was unplugging the device. Within an instant, I smelled the scent of burning flesh, and my arm was throbbing. Did I touch the electrical ground wire?

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