What Does "High Voltage" Mean?

High voltage refers to an electrical potential large enough to cause injury or damage. It's the force that pushes electrons through a conductor and is essential for powering everything from homes to industries. But what makes a voltage "high," and how does it affect safety and efficiency? Discover the electrifying details as we delve deeper into the world of high voltage.
Pamela Pleasant
Pamela Pleasant

The term “high voltage” is generally used to describe an electrical current that is strong enough to harm humans and sometimes also animals if they come into contact with it. It’s not an exact measurement of electricity as much as it is a warning that advises people to maintain their distance. The phrase is perhaps most commonly seen on labels and signs, usually accompanied by other warnings or icons indicating the risk of electrical shock, injury, and death. In general, anything that produces more than 230 kilo volts is considered to be high voltage and extremely dangerous. There are exceptions, though. What makes a voltage high enough to warrant these precautions is usually as much about its presentation as its actual measurement. Very well insulated sources can carry extremely steep voltages but may not require a warning if there is no risk to people. Alternatively, currents that might generally be thought of as rather weak can be considered dangerous if they are coursing through raw cables, for instance, or if they’re relatively easy for humans to access accidentally or inadvertently.

Basic Concept

A multimeter, which can be used to measure voltage.
A multimeter, which can be used to measure voltage.

Volts are a common unit of electrical measurement. More precisely, they represent electrical potential, and can be used to categorize and determine how much power is needed for a given task, device, or procedure. Electrical charges are common in nature, and at low frequencies they don’t pose any unusual threat to people or animals. The amount of energy that needs to be harnessed to do things like power electrical grids for cities and towns or provide electricity to buildings like hospitals is usually immense, however. These sorts of concentrated voltage situations is where warnings come into play.

Danger to Humans

Power lines are considered to have high voltage.
Power lines are considered to have high voltage.

In nearly all cases, the warning is only issued in situations where humans are likely to come into danger. As little as 40 volts can be considered high voltage in the right circumstances. If applied to human skin, 50 volts can cause the heart to fibrillate. This means that the heart will start to experience irregular and rapid heartbeats and the muscles may also contract. Much lower voltages can be fatal if the skin is moist or wet, because water allows electricity to penetrate the skin at a faster rate. This is one of the reasons why it’s dangerous to use electrical appliances in or near the bath, for instance, and is also why most swimming pools are closed during electrical or lightening storms. An open wound also can allow the electricity to penetrate the skin faster.

How the Labeling Determination is Made

Depending on the setting, a series of classifications determine the point at which voltage poses a danger. The International Electrotechnical Commission (IEC) has established safe standards for electrical applications. These standards set the acceptable amount of energy needed for solar technologies, semi conductors, as well as home appliances.

If there is no stored energy and the appliance or machine cannot produce a current, there is no danger of severe electrical shock. Even if there is high voltage present, it may not be enough to seriously injure a person. For example, static electrical sparks can be measured at around 700 volts, but may only produce discomfort for a few seconds. This type of electrical output can produce pain but it will not usually affect the heart or muscle tissues.

Measuring Voltage

Voltage can usually be measured in a couple of different ways. Utility companies and electrical suppliers often measure their currents periodically, both to ensure safety and consistent delivery patterns. Regulators cnad community health experts sometimes monitor known voltage exposures to promote public well-being and to look out for any health risks assumed by employees or technicians. Different countries have different laws with regard to inspection, measurement, and safety protocol.

In general, coming into contact with power lines is one of the most common causes of fatal electrical shock. These lines can produce more than 50 volts of electricity and can be extremely dangerous. Electrical cables buried underground can also produce enough electricity to be fatal if they are disturbed by digging equipment.

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    • A multimeter, which can be used to measure voltage.
      By: pavantt
      A multimeter, which can be used to measure voltage.
    • Power lines are considered to have high voltage.
      By: Gina Sanders
      Power lines are considered to have high voltage.