What is a Brownout?

A brownout is a temporary reduction in voltage in utility lines that can cause lights to dim and equipment to fail. Brownouts typically last a few seconds but can extend for hours.

What is the Difference Between a Blackout and a Brownout?

A blackout, also known as a power outage, is a complete loss of electrical power in a specific area or across an entire region. A brownout is a temporary, partial reduction in voltage levels within an electrical power supply system.

What Causes a Brownout?

Brownouts can be caused by a number of different issues.

  • Increased demand for energy during extreme weather conditions can strain an insufficient electrical grid infrastructure causing brownouts.
  • Outdated or failing equipment in the power grid can cause brownouts.
  • Other issues like damage to electrical lines or disruptions in power transmission can also cause utility brownouts.
  • In rare cases, overburdened utilities can intentionally reduce their voltage output to manage unusually high energy demands. This temporary reduction of voltage can help the power company prevent a complete blackout.
  • Local equipment that draws massive amounts of power such as motors or air conditioners can cause momentary brownouts to occur.
  • Faulty Wiring can also cause a brownout.

What are the Effects of a Brownout?

Brownouts are noticeable because they cause the lights to dim and ceiling fans to slow down, but the more serious effects of the lower voltage during brownouts are the strain of brownouts on electrical equipment or appliances. In residential settings, this can lead to diminished performance, data glitches or malfunctions in electronic devices, potentially damaging sensitive equipment like computers, refrigerators, and air conditioners. Commercial buildings may experience disruptions in operations, as critical systems, machinery, and computer networks may be adversely affected. Extended brownouts can destroy electrical components and cause hardware failure.

At the end of a brownout period a voltage surge or spike often occurs, which can also damage electrical equipment.

How to Fix or Reduce Brownouts

Reducing the occurrence of brownouts involves a combination of infrastructure improvements, demand management, and the integration of smart grid technologies. Individual users can also do their part to reduce their impact on the power grid by installing more energy-efficient appliances or adjusting thermostats during periods of high energy demand.

How to Protect Computers and Other Electrical Equipment from Damage Caused By Brownouts

Line conditioners and Uninterruptible Power Supplies (UPS) are the best defense against brownouts. Line conditioners and UPS devices keep the voltage constant during brownouts, filter out noise, and may also have surge protectors to protect against voltage spikes that often occur at the end of brownouts. In addition, a UPS device will also temporarily maintain power if the power goes out. A surge protector, also called a surge suppressor or surge arrestor, is not designed to prevent a drop in voltage during a brownout, but is useful in preventing damage to equipment at the end of the brownout when a voltage spike often occurs. Combining surge protectors with other measures like uninterruptible power supplies (UPS) and line conditioner voltage regulation systems can enhance the resilience of electronic equipment against the adverse effects of power fluctuations.

What is the Difference Between a Line Conditioner and a UPS?

A line conditioner is primarily designed to regulate and improve the quality of the incoming electrical power. While line conditioners can provide some protection against power spikes and minor voltage variations, they are not designed to offer extended backup power during outages. A UPS is designed to provide temporary backup power during electrical outages, ensuring continuity of power to connected devices. A UPS is more comprehensive in terms of protection, as it can offer both short-term power backup and voltage regulation. It is especially useful for preventing data loss, protecting critical equipment, and allowing time for devices to be shut down during a power outage.

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Warning: For safety, call a licensed electrician or consult the NEC®. All licensed electricians have passed examinations covering the National Electric Code®, know state and local building codes, and may carry insurance to cover damages.