What is amperage?

An electric current consists of a flow of electrons through a conductive material. Said current is characterized by several properties and parameters, such as intensity, power or voltage.

The intensity of an electric current is number of electrons that flow per unit of time through the material, and in the International System of Units it is measured in ampswhose symbol is A. One ampere is equal to one coulomb per secondthat is, a stream of 6.241 x 1018 electrons per second.

When you talk about amperagetherefore, we are talking about electric current intensity expressed in amperes.

When a person receives an electrical shock, the amount of electrical charge that passes through the body is what determines the severity of the shock, that is, the amperage and not the voltage as is commonly thought. A flow of only 0.1 – 0.2 A through the human body is usually lethal due to its effects on the heart, although there are cases in which higher discharges have been survived due to strong muscular contractions that have acted as a barrier.

Electrical devices and appliances can be classified according to their amperage, that is, the amount of electrical energy they demand from the network when they are operating under normal conditions. When electricians talk about household electrical current they may refer to:

  • strain: if it is measured in volts it is the voltage
  • intensity: if it is measured in amps it is the amperage
  • power: measured in watt-hours (Wh) or kilowatt-hours (kWh), but be careful, wattage does not exist.

Amps vs Volts

The flow of electricity through the electrical wiring in a house could be likened to the flow of water through a system of pipes. The voltage (voltage) could be compared to the pressure of the water and the amperage to the amount of water that passes a certain point every second.

The hydraulic energy provided by the water would be the power, which in electricity is measured in watts. At lower pressure, less water can flow out of a small tube compared to a large tube for the same amount of time. The size of the tube could be assimilated with the concept of electrical resistance, a small tube would offer more resistance.

Electricity reaches homes through wiring that is ultimately connected to a generator. To minimize the loss of energy due to the resistance of the electrical wiring, transformers are used that transmit electricity with a high voltage that can overcome the resistance of the wiring.

Before the electricity reaches the homes, transformers are again used to regulate the voltage so that the electricity reaches the houses with an adequate voltage. This voltage of the supply networks is not the same throughout the world, for example, in Europe a voltage of 220-230 V is used and in the United States 110 V.

But voltage measures the electrical potential available, not how much is used. Here the amperage comes into play, that is, the number of electrons or electrical charge that has to come out of the electrical cables towards the devices connected to the network.

An appliance, such as a refrigerator, may need 100 A, a toaster may need 10 A, but they both work on an electrical network with the same voltage. Consumption is measured in kWh (kilowatt-hours) which is the amount of energy used per unit of time.

The role of fuses

The amperage is a parameter that must be controlled to protect appliances, prevent overheating of the wiring or short circuits. Fuses are small devices with a metal filament designed to withstand a certain maximum amperage. For example, a 30 A fuse will break if a higher amperage reaches it from the mains; When the fuse breaks, the electrical current is cut off and the devices connected to the network are protected.

Most electrical appliances of a certain size/quality usually incorporate their own internal fuses. Other electrical installations, such as automobiles, also use fuses to protect the entire electrical system of the vehicle.

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