Growing up, my dad was the one that took on any of the electrical projects around the house. He taught me a few things about wiring, including putting a new plug casing on an appliance wire. Of course, I was informed that the grounding wire was the most important to connect, otherwise, it wasn’t safe. But I was a bit older before I learned all the reasons why earthing appliances is essential.
1. Prevent Damage to Appliance
During power surges, grounding provides a way for excess electricity to leave the appliance. It saves the electrical components of the appliances from being fried by big surges.
This is possible because the earth conductors provide the least conduction resistance, meaning that it is easier for electricity to travel through the earthing cable and get dispersed. This is the path it takes instead of traveling through your appliance and damaging it.
The protection provided by earthing wires doesn’t just apply to power surges but to all possible circumstances in which too much electricity is channeled into an appliance.
It also helps to balance out and direct the electricity in an appliance, ensuring that no part receives too much while it helps to get the power to the correct spots. This prevents overloading that could damage the circuits of the appliance because the voltage is stabilized.
When electricity overload damages an appliance, it can compromise circuits and wires, which isn’t always an obvious issue. Damaged appliances can be dangerous, and without correct earthing, the appliance can direct that electricity into you, especially if it has a metal casing.
While the safety of your household is foremost, the damage to the appliance itself can be extensive and expensive.
If the electrical system of the appliance is overloaded or unbalanced, the whole thing can break or burn out (such as dryer heating elements). It might not be possible or worth the price to repair the appliance, meaning you will need to purchase a new one.
2. Protect Users Against Electric Shock
If you think about the electricity in your home, you will notice that electric appliances are the points in the electrical system that you will most frequently come into contact with. You aren’t going to be in your walls and ceiling, fiddling with the wires.
As the points of most common contact, it is absolutely essential to prevent these appliances from being able to generate life-threatening shocks. Earthing the appliance is the main way of preventing it from holding and passing on enough electricity to injure you.
Otherwise, there are several electroshock effects that can result:
- Burns (ranging from first- to third-degree); these can occur on the skin and internally.
- Muscle pain.
- Muscle contractions.
- Respiratory difficulty.
- Arrhythmias (dysregulation of your regular heart rhythm).
- Loss of consciousness.
- Cardiac arrest.
The damage to your nervous system, circulatory system, and muscular system can be mild to fatal, depending on the degree of the electroshock. An appliance like a tumble dryer that pulls 240 volts of electricity would be terrifying without being earthed.
Earthing the appliance eliminates excess, dangerous electricity before it can harm you. The grounding or earthing wire is designed to be the fastest, easiest way for electricity to pass into the ground and prevent injury.
You can experience electroshock from an appliance because the human body is an electrical conductor. Without a grounding wire, you are the quickest path to the ground, and you are at risk for electrocution.
Below is a list of appliances that are high risk, which commonly includes appliances that are used near or with water:
- Extension cords: these are prone to broken or fraying wires. They are also dangerous when used with powerful appliances.
- Any appliance you use with a bathroom outlet is riskier because of the exposure to damp and condensation. This frequently includes hairdryers, flat irons, electric razors.
- Kitchen appliances like toasters, kettles, and blenders.
- Washing machines.
- Water heaters.
- Electric dryers.
3. Minimize the Risk of Electrical Fires
Whenever you have an excess of electricity that can damage the electrical circuits, there is a risk of electrical fires starting. The problem with damaged or worn wires is that this can cause the appliance to pull more power, which exacerbates the fire hazard.
Earthing helps preserve the wiring in the appliance by helping it function optimally with the right balance and distribution of electricity within the circuits.
This is why the earthing wire is so important. Instead of allowing that electricity to flood the appliance where it can start fires, excess electricity that the electrical system cannot hold is discharged safely.
Sometimes, people will remove the grounding wire of an appliance to make it fit into a two-prong socket. However, this is not advisable as not only are grounding wires a safety feature, there is a reason why the appliance is designed for a three-prong socket.
Larger appliances like refrigerators require higher amounts of electricity than a small outlet can supply. Using an outlet that cannot cope with the power the appliance draws will overload the outlet. This can also cause fires as the wires break and fray with the excessive load.
4. Allow Metal to Be Safely Used in Appliances
Metal is a durable material frequently used in large appliances. However, metal is also an electrical conductor.
Anything over 500 volts can cause a severe shock to our bodies. Large appliances generally use more electricity, which means you do not want that current reaching you when you touch the metal fridge or washing machine.
The wires in metal appliances are encased and protected so that they are not in contact with the parts of the appliance that you touch.
Unfortunately, there are instances when wires can become broken and exposed, able to come into contact with the metal casing of the appliance. This can be very dangerous, and these compromised wires are not obviously out in the open. So, you might touch the appliance without realizing it is not safe.
Earthing the appliance means connecting a metal conductor that more easily carries electricity than the metal casing.
Appliances will commonly trip the circuit breaker (internal or external) if the grounding wire is not functioning or connected in order to prevent shocks and protect you.
How Are Appliances Earthed?
Appliances are earthed using a wire. There are three main wires in appliances:
- Active wire: supplies power.
- Neutral wire: transports power back.
- Grounding wire: a path for electricity to enter the ground without harm or hazard.
The grounding wire is made of copper, a good conductor of electricity. It is connected from the electrical system of the appliance to the earth terminal in the service panel to allow for electricity to discharge from the appliance safely. This means that when there is too much electricity for the neutral wire to handle, it can go through the earth wire.
Appliances that need grounding have three plug prongs and three wires that connect to these different terminals. Most of the time, you will just need to plug your appliance in to ground it, as they are equipped with an earthing wire (when required) in the attached plug.
Any appliance that might require special attention or steps involved in the wiring should come with clear instructions for how to correctly earth it in the user manual or installation guide.
A qualified electrician should do any large rewiring project for your electrical system in order to make sure your wiring is up to code standards and to sign off on code compliance.
How to Tell if Appliance Is Earthed Properly
A professional will be able to check that your appliances are properly earthed. So, when in doubt, you should always call an electrician.
As mentioned, appliances that have three prongs are earthed when plugged in. However, just because your plug has three prongs does not guarantee that it is earthed.
Some situations can result in an appliance’s grounding wire being damaged, broken, or disconnected by being bent or pulled, such as when an appliance is being moved. The wiring can also be faulty if the earth wire isn’t correctly connected due to a repair, modification, or manufacturing error. Alternatively, wiring can become compromised as it ages and wears.
If you have a three-prong plug, you know that there is a grounding wire, and you can go ahead and test the appliance as per the multimeter instructions.
In general, to test plugs in this way, you will likely have to put a contact onto the casing and one on a known and well-earthed metal item once you have unplugged the appliance. This could be a metal pipe or even the screws found on your electrical faceplate. You can also check the continuity from the appliance’s earth wire (or plug prong) to the metal casing.
If your ohm readings are low (often two or less), your appliance should be sufficiently earthed. Any strange reading of infinity (o.L) or over 120 means that you need to clean the contacts on the meter or it is not working.
Smaller appliances are easier to test as larger ones might require certain components to be dismantled and tested individually. If you are concerned about an earthing problem, please unplug the appliance and call a professional before using it again.