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The Home Depot

What Causes an Electrical Disturbance?

Pro Referral > Home Guides > Electrical > What Causes an Electrical Disturbance?
What Causes an Electrical Disturbance?

If you notice electrical disturbances that affect the power to your electrical system, there may be a variety of causes behind these occurrences. Because of the broad spectrum of causes and effects, it’s helpful to learn about electrical power disturbances in general to understand the concepts.


Although electrical disturbances can be inconvenient and irritating, once you understand the causes, you’ll be in a position to resolve them as quickly as possible.

  1. 1.Types of Disturbances

    If you have short circuits in your electrical system or undersized electrical circuits, you may notice power surges.

    A small form of electrical disturbance – a surge – spans a split second and results in an increase in voltage levels. A spike occurs with an instant and very large increase of voltage levels. Slightly longer than a surge, a “sag” or brownout may last a few seconds or could last for several hours. When a sag or brownout occurs, there will be a decrease in voltage levels. If a blackout occurs, you will experience a complete absence of electricity.


    You may also notice small disturbances known as electrical noise. These electromagnetic interferences happen with disruptions in sine waves from utility power.

  2. 2.Causes

    If you have short circuits in your electrical system or undersized electrical circuits, you may notice power surges. Surges can also happen when you turn off a heavy-duty appliance. If lightning strikes nearby, this can cause a spike. Spikes also occur from downed power lines, thanks to an accident or storm.


    A brownout may happen if a utility company decreases voltage levels in response to peak load times. These rolling brownouts often happen during seasonal heat waves. A blackout may occur due to high demands on a power grid. Blackouts can also occur from ice storms, lightning storms or equipment failure.

  3. 3.Potential Damage

    If electrical equipment receives a power surge, components may receive excessive wear. A power spike could destroy hardware equipment, cause processing problems or contribute to data loss. A brownout could cause data loss or corruption or affect the efficiency of equipment. For this reason, utility companies warn customers to enable people to take protective action. A blackout could cause either minimal or total data loss or damage to a computer hard drive.

  5. 4.Prevention

    To minimize damage from power surges or spikes, plug electrical equipment into a surge protector or suppressor. A surge protector absorbs excess electricity by pushing it to the ground line and away from the electrical equipment plugged into the protector.


    To minimize damage from brownouts and blackouts, install an uninterruptible power supply system in your home. When you have a UPS system, your electrical system will change to battery power upon the detection of brownout or blackout situations. While you won’t have extended power with a UPS system, you will at least have a few minutes to save current work and shut down your systems properly. UPS systems also absorb surges and spikes and provide monitoring for safe maintenance of an electrical system.

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