Power comes to your home.
Power comes to your home through wires.
Different lands use different power. Some places use more or less power. This is why plugs look different in other lands.
Some wires help keep you safe. They move extra power into the ground. This can stop a shock.
We use power to cool our homes. We also use it to cook food. It is very helpful for us every day.
Mains electricity is the power sent to homes and businesses.
Power systems are different in every part of the world. Most places use alternating current, or AC. This is a type of power that changes direction. Different lands use different levels of voltage. Voltage is the pressure that pushes electricity through wires. Most of the world uses 230 volts. In North America, people mostly use 120 volts. Because of this, plugs and sockets look different in different countries. This helps keep people safe from using the wrong power.
Safety is a big part of how wires work. Many systems use an earth wire. This is a wire that sends extra power into the ground. It helps stop people from getting an electric shock.
Mains electricity is the general-purpose power supply sent to homes and businesses.
Electricity moves through wires using a specific way it works called alternating current, or AC. In this system, the power changes direction. Most of the world uses a voltage of about 230 volts. This voltage is the pressure that pushes the electricity through the wires. In North America, the common voltage is 120 volts. The frequency, which is how often the current changes, is usually 50 Hz or 60 Hz.
Different regions have used different power standards for a long time. In the early 20th century, many different combinations of voltage and frequency were used. Some areas even used direct current, or DC, instead of alternating current. Today, most public power systems use AC. Some places in Canada call their mains electricity "hydro." This is because more than half of their power comes from hydroelectricity. 
Every country has its own rules for plugs and wires to keep people safe.
We use mains electricity for almost everything in our homes. In the United States, space cooling and heating use the most energy. Water heating and refrigeration are also very large uses for electricity. Even small items like clothes dryers and computers need this power to run. Some devices, like laptops, use an adapter to change the power they receive. This allows them to work with different voltages and frequencies.
Mains electricity is a general-purpose supply of alternating current, or AC. This type of electric power is delivered to homes and businesses through an electrical grid. People use this power to operate everyday items like lamps, televisions, and computers. You can access this energy by plugging devices into a wall outlet, also called a receptacle or socket.
Most modern power systems use alternating current (AC) rather than direct current (DC). In an AC system, the electric current changes direction periodically. This is measured by frequency, which is the number of times the current changes direction per second. Most of the world uses a frequency of 50 Hz. North America and other regions typically use a frequency of 60 Hz. 
Power systems are defined by several specific technical parameters. These include voltage, frequency, plug and socket types, and earthing systems. Voltage is the electrical pressure in the system, usually expressed as root-mean-square (RMS) voltage. Most global voltages fall between 100 V and 240 V. In much of the world, the nominal voltage is 230 V. In North America, the common combination is 120 V at 60 Hz.
Electricity is delivered through complex building wiring. Most portable appliances use single-phase power. This involves two or three wires at each outlet. One wire is the neutral wire, and the other is the live wire, also called the phase or active wire.
Safety is maintained through several protective devices. Circuit breakers and fuses are used to prevent overheating and fires. They detect if there is a short circuit or if the current is higher than the wires can handle. This is known as overload protection. Another device is the residual-current device, or ground-fault circuit interrupter. This device detects a ground fault, which happens when current flows through something other than the neutral or live wires.
We use electricity for many different tasks in our daily lives. In the United States, residential electricity consumption is split among many uses. Space cooling accounts for about 15% of use, while space heating uses 14%. Water heating is also significant at 12%. Refrigeration uses 6%, and lighting uses 4%. Other uses, such as small electric devices and outdoor equipment, make up about 34% of total consumption.
Large-scale electrical needs require different setups than small household items. While portable tools use single-phase power, industrial plants often use three-phase power. This provides higher voltages for large equipment. In some parts of Europe, residential supplies can even be 400 V three-phase power. This can power heavy tools like log splitters or large kitchen stoves. The choice of voltage in a region is often due to history. Once a voltage is established and equipment is widespread, changing it is very expensive and difficult.
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