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What Causes Power Surges?

what causes power surges

In the complex world of electrical systems, power surges represent a common yet often misunderstood phenomenon. These brief spikes in electrical voltage can disrupt the normal flow of power and, in some cases, cause significant damage to household appliances and electronic devices. Understanding the causes of power surges is crucial for both homeowners and businesses alike, as it can aid in taking professional preventative measures to safeguard valuable equipment. This article delves into the various factors that contribute to power surges, shedding light on this electrical occurrence.

Understanding Power Surges

Before exploring the causes, it is essential to grasp what a power surge is. A power surge, or transient voltage, is a sudden increase in voltage significantly above the designated level in a flow of electricity. In the United States, standard voltage for home and office buildings is 120 volts. When the voltage exceeds this level, even for a fraction of a second, a power surge occurs.

External Causes of Power Surges

  1. Lightning Strikes: One of the most dramatic and powerful causes of power surges is lightning. A single bolt of lightning can carry over 100 million volts of electricity. When lightning strikes near a power line, whether it's overhead or underground, the energy can boost electrical pressure by millions of volts. This can overwhelm the electrical system in a home or building, leading to significant damage.

  2. Power Outages: Surprisingly, the restoration of power after an outage can also generate a power surge. When the electricity is suddenly reestablished, it can create a wave of electrical pressure that disrupts the steady flow of voltage.

  3. High-Power Electrical Devices: Large appliances like air conditioners and refrigerators require a lot of power to turn on and off. The on-off action of these devices can create sudden, brief demands for power, leading to short surges that can affect the entire electrical system.

Internal Causes of Power Surges

  1. Faulty Wiring: Damaged or exposed wiring can not only be a significant fire hazard but can also contribute to power surges. Faulty wiring can lead to an increase in electrical pressure, resulting in a surge.

  2. Overloaded Circuits or Outlets: When too many devices are plugged into a circuit, it can become overloaded. This overload can cause small, repeated power surges that, over time, can damage electronic devices and appliances.

  3. Cycling On or Off of Larger Appliances: As mentioned earlier, devices with large power demands can create surges within a home. These surges may not be as dramatic as those caused by lightning, but they can still be harmful over time.

Preventing Damage from Power Surges

While power surges are often inevitable, there are ways to protect your home and devices:

  • Surge Protectors: Surge protectors can safeguard electronic devices by absorbing or redirecting the excess voltage away from the devices.

  • Whole-Home Surge Protection: This involves installing a surge protector at your electrical panel, offering another layer of defense against external surges.

  • Regular Electrical Maintenance: Regularly inspecting and maintaining your home’s electrical system can prevent issues related to faulty wiring and overloaded circuits.

Power surges are an inherent part of our electrical systems, but understanding their causes is the first step in mitigating their potential damage. By taking proactive measures and being aware of both external and internal sources of power surges, homeowners and businesses can protect their valuable electronics and appliances. Contact a professional electrician for more info or to prepare your home for unexpected voltage spikes.


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