Why Electrical Earthing Is Important for Household Appliances

Aug 12, 2023

Electricity is useful, but it's also dangerous. Here's how you stay safe with proper electrical earthing.

You may have noticed that some electric and electronic devices have three-pin plugs, requiring a three-pin socket or adapter for power. These devices are usually almost identical to those with two-pin plugs, except for the third pin, which provides electrical earth or ground connection.

So, what is the significance of this third pin? And why is it essential for electrical appliances to have a ground connection?

If you've ever experienced an electric shock while touching an appliance, like a washing machine or a microwave oven, it might be due to poor (or no) earthing connection.

The ground connection or earthing connection is a basic necessity for electrical safety. This function directly carries any stray electrical current to the ground by offering a low-resistance path. It is crucial to protect users and equipment in case of a fault or vulnerability and for reliable operation.

If you've seen a thick metallic wire on the outside buildings that goes straight into the ground or is connected to a metallic rod, this is often the earthing wire. So, if any appliance inside the structure with a grounding pin suffers an electrical fault, it will discharge the electricity through this wire or rod instead of the user touching it.

However, remember that not all wires inside the ground are earth wires. Some insulated wires may belong to an underground electrical power distribution network or your internet provider.

Equipment earthing is the physical connection of an appliance's outer case to an earth zero voltage potential. This electrically insulates the device's internal circuitry from the outside environment.

Equipment earthing is crucial for user safety because it ensures that any current that might harm its user is redirected to the ground instead. So, if an internal fault or short circuit results in the phase (or live) wire coming into contact with the device's case, it won't harm the person handling it at that time. And although the excess current through the appliance will activate the circuit breaker, earthing is still crucial as the circuit breaker might not cut the power before someone handles the device.

Grounding or neutral earthing is similar to equipment earthing in that it protects against accidental electrocution. But instead of connecting an appliance's unpowered case to the earth, it connects the neutral wire directly to the earthing terminal. This is mainly used to prevent an electrical overload by allowing excess voltage to dissipate into the ground.

Electrical earthing will keep you safe and help your devices last longer. These are five key reasons why it does so.

Static electricity can build on an appliance surface from neighboring equipment or when a user touches it. Sometimes, this charge builds up huge voltages on its surface. If this build-up finds a way to reach your device's internal circuitry, then electrostatic discharge (ESD) can cause severe damage to it.

But with proper earthing, this static build-up will be discharged via the ground prong, thus avoiding any damage to your device's sensitive electronics.

You might have seen many buildings and some houses with a pole with a metallic ball and a nail-like structure. These are called lightning arrestors, which transfer electrical energy from lightning strikes directly to the ground via a low-resistance wire. This helps prevent the millions of volts that lightning strikes deliver from damaging your electronic devices.

With proper earthing, you ensure that the voltage brought by lightning strikes is safely dissipated to the ground. This prevents property damage and physical injuries, allowing you to use your appliances safely even during a thunderstorm.

Any electronic device must be electromagnetic compliant before it can be used reliably. This means that it must not emit electromagnetic radiation that interferes with the operation of other devices and is not susceptible to the electromagnetic energy it will encounter during its normal operation.

Proper grounding is one of the most important aspects of electrical and electronic appliances to ensure they comply with these requirements. It also helps determine what will happen if a device gets unintentional faults, electrical transients, or electromagnetic interference.

When your machine has proper grounding, it improves the electromagnetic compatibility of electrical circuits, allowing engineers to control unwanted electromagnetic emissions.

An earthing connection protects anyone using or touching an electrical appliance if it suffers from an electrical fault. Because the earthing connection provides the path of least resistance between the external body of the device and the earth, any voltage or electrical charge build-up will discharge through it.

So, even if a device is damaged electrically and you accidentally touch it, the earthing connection ensures that the excess electricity won't travel through you.

Earth is considered a common reference point for the entire electrical system. It is possible to maintain a balanced voltage level by grounding the electrical system, preventing circuits from becoming overloaded and damaged.

The easiest way to know if your house has electrical earthing is to check your outlets. If they have three holes, then your home is most likely grounded. That's because the third hole is where your appliance's grounding pin attaches to.

But if you want to be sure, you should check out the main meter of your residence. Does it have a grounding rod with a grounding wire? If yes, then your home has electrical earthing. Nevertheless, you should call a professional electrician to test all your outlets if you feel that some of them aren't properly connected to the ground.

Grounding your electrical system is one of the primary safety protocols to avoid accidents with electricity. It also helps ensure the smooth operation of your electrical and electronic appliances, allowing them to last longer.

By grounding, you protect against electrocution and prevent static from damaging your appliances. Moreover, it protects against external factors, like lightning strikes and power surges. So, if you plan to build a home or are looking to buy one, ensure that its outlets have a ground plug, allowing you to earth any device you plug into it.

Ummara is a staff writer at MUO whose work focuses primarily on Linux. She has a degree in Telecommunication Engineering and has been writing about Linux for about 3 years.