What are Power Brownouts and How Are They Different From Blackouts?

Brownouts are temporary voltage drops often caused by severe weather or created intentionally by utility companies, which can harm home electronics and appliances. Unlike blackouts, where electricity is completely cut off, brownouts deliver less power than normal, which can cause appliances to malfunction, harm sensitive electronics, and even create fire hazards if left unchecked.

Why would an electric company intentionally create a brownout? This guide will dive into what they are and how to stay safe, as well as why they occur, and how to protect your devices.

A brownout signifies reduced voltage, about 10-25% less than the usual amount. A blackout, on the other hand, is a complete loss of power.

Blackouts can occur suddenly and last for an unpredictable duration, often triggered by severe weather or equipment failure. Electrical brownouts can be controlled and managed by utility providers to stabilize the power grid during peak energy use, though most occur accidentally due to weather or other power sources overloading.

These low-voltage events typically last for a few hours and tend to be shorter than most blackouts. Voltage sags, sometimes confused with brownouts, are short dips in voltage of 10% or more, but these only last a few minutes.

When too much power is used by many people simultaneously, the system can become overloaded, leading to voltage drops. This is especially common during peak hours when everyone is using their heating or cooling systems, leading to power interruptions. Aging infrastructure can also lead to the overextension of a grid, which could result in this type of overload.

Severe weather usually causes blackouts, but can lead to brownouts if equipment damage reduces grid capacity without fully cutting power. Storms, heavy winds, and other weather phenomena can disrupt the power supply, leading to damaged power lines, power failures, and low-voltage events.

A power company may sometimes intentionally enact brownouts to reduce the load on the system and prevent a total blackout during periods of peak power demands.

Devices like computers, smartphones, and home entertainment systems often fail to operate efficiently during voltage sags, leading to unexpected behavior and malfunctions.

Some appliances will continue to operate at a lower capacity, such as flickering lights or increased motor failures. HVAC systems, washing machines, and refrigerators can also suffer during brownouts. They tend to run hotter as they demand more current to maintain their output, increasing the risk of overheating and shortening their lifespan. Prolonged under-voltage conditions can result in costly electric motor failures and decreased productivity over time. (Energy.gov p. 109)

Other devices may shut off or reboot, including computers, smart TVs, or sensitive medical equipment. This can also lead to data loss or corruption in computer systems, as insufficient voltage levels can cause write failures in disk drives and stall an internet connection. Control circuits in various electronic devices may malfunction, leading to erratic performance and potential damage.

Knowing how to stay prepared includes understanding when and why power outages like brownouts and blackouts might be necessary.

In February 2021, Winter Storm Uri triggered the largest manually controlled load-shedding event in U.S. history, with ERCOT ordering 20,000 MW of rolling blackouts to prevent grid collapse. Though these events were not brownouts, but full outages, this is a clear example of instances where utility companies in Texas had to interfere with electrical access in order to avoid losing the entire statewide grid.

Recommendations from energy-focused entities like FERC and NERC called for stronger mandatory winterization standards, better gas-electric coordination, improved use of weather forecasting, and refined rolling blackout strategies to prevent future large-scale failures.

Regardless of its source, when a brownout hits, your priority is to protect your devices and stay safe. Even a short voltage drop can cause permanent damage to sensitive electronics if not handled properly.

Immediately disconnect computers, TVs, gaming consoles, and other sensitive devices. Sudden voltage fluctuations can fry circuits or cause data loss.

Tip: Leave essential appliances like refrigerators plugged in, but monitor them carefully if the brownout persists. Refrigerators and freezers can usually survive 4+ hours without power if unopened. This way, you can avoid food spoilage if the brownout, or even a blackout, doesn’t last for too long.

Turn off unnecessary lights, appliances, air conditioners, and heating systems when possible. Lowering your household demand helps stabilize the local grid and may reduce the duration of the brownout. We’ve seen this before, especially in Texas summer peak season. Conserving energy will only help to restore the grid faster.

Check your utility’s real-time outage map or app for updates. In Texas, this might include:

• Oncor (DFW, Waco, Mid-Texas) – Outage Page | Call 888-313-4747
• CenterPoint Energy (Houston Metro) – Outage Tracker | Call 713-207-2222
• AEP Texas (Austin, San Antonio, Waco) – Outage Page | Call 1-866-223-8508
• TNMP (North Texas, Lewisville) – Outage Page | Call 888-866-7456

Receiving alerts and updates ensures you know the expected duration and can plan your actions accordingly.

Once the brownout ends, wait about 10 minutes before reconnecting sensitive electronics. This pause ensures the voltage has stabilized and prevents immediate damage from post-brownout surges.

Without proactive measures, brownouts can lead to severe issues such as damaged equipment or data loss. Planning for possible voltage drops and taking preventive actions can help reduce your risk.

LED lights are an excellent choice during brownouts due to their energy efficiency and resilience to voltage fluctuations. Unlike incandescent light bulbs, LED lights use less wattage to produce the same amount of light, which means that they require less energy to run.

Surge protectors are designed to protect electronic devices from sudden power surges that can occur after a brownout. They work by absorbing extra voltage and preventing it from reaching your appliances, safeguarding them from spikes.

Plugging sensitive electronics into surge protectors is an effective way to shield them from electrical surges. To protect all of the circuits in your home, consider installing a whole-house surge protection system connected to your main panel.

Uninterruptible Power Supplies (UPS) are backup power systems designed to provide power to devices during brownouts or blackouts. A UPS gives you a stable voltage output during fluctuations that allows your devices to keep running without pause.

Investing in a UPS protects your critical appliances and electronics from potential damage caused by brownouts. This is especially beneficial for sensitive electronic equipment such as computers, servers, and medical devices.

Even a small power bank to keep your phone or laptop on can make a huge difference during a long period without power.

For a more robust defense against brownouts, consider long-term solutions to ensure a stable supply voltage.

Voltage regulators are devices that maintain consistent voltage levels and smooth out power fluctuations. An Automatic Voltage Regulator (AVR) ensures stable output voltage despite input irregularities, preventing operational disruptions and prolonging the lifespan of your appliances.

Constant Voltage Transformers (CVT) are more common in industrial or lab environments, and leverage magnetic principles for high-precision voltage regulation without moving parts.

Surge protectors can also complement voltage regulators by managing voltage spikes that occur after brownouts. Together, these solutions provide comprehensive protection for your electrical devices and systems.

Backup generators are essential for maintaining power supply during prolonged brownouts. By providing backup power, these generators ensure that your home or business can remain operational even during long periods without power. An energy provider can help you choose the right generator for your needs.

Investing in a reliable backup generator prevents disruptions and protects your essential appliances and systems from damage.

These condition monitoring devices ensure optimal performance and enhance the safety of your electrical equipment systems through digital control circuits, control signals, and logic circuit

This means that the monitors help homeowners see that their utility power stays stable by doing things like monitoring electrical power quality and providing alerts when voltage levels drop.

Of course, power sources that are off the electrical grid like solar panels and personal generators can also be a great way to help with voltage reduction and avoid issues like these.

Man, an electrical technician working in a switchboard with fuses. Installation and connection of electrical equipment. Professional with tools in hand. concept of complex work, space for text.

Regular maintenance of your electrical system is important. Conduct routine checks on your wiring to identify and address any worn or damaged components. Inspecting outlets and switches can prevent local issues that might contribute to voltage drops and affect the flow of electrical current.

Maintaining and upgrading your circuit breakers and electrical panel can also reduce the risk of brownouts and ensure the efficiency of your home’s electrical system, helping to avoid potential power problems.

Severe weather can increase the likelihood of brownouts and blackouts. To stay safe:

• Sign up for updates through local emergency alert systems
• Use a battery-powered radio for the latest information
• Keep a paper copy of emergency contacts in case of a power outage

Ensure your car’s gas tank is at least half full to facilitate evacuation if necessary, and avoid using unnecessary electrical appliances during severe weather to minimize the risk of fire hazard and electrical fires during surges that may occur after a storm-induced brownout.

Brownouts, though less severe than blackouts, can still cause significant disruptions and damage to your electrical devices. By understanding their causes and effects, taking immediate action during a brownout, and implementing preventive measures, you can minimize potential damage and ensure the safety of your home and appliances.

Long-term solutions such as voltage regulators, backup generators, and smart power monitors offer enhanced protection against brownouts. Regular electrical maintenance and safety measures during severe weather further strengthen your defenses.