If you’ve ever experienced a sudden power outage or flickering lights during a storm in San Francisco, you’ve probably been exposed to a power surge—even if you didn’t realize it. These invisible spikes in electricity can silently damage your electronics, appliances, and even your home’s power systems.
Understanding what a power surge is, what causes it, and how it behaves in both internal and external scenarios is the first step toward protecting your home. In this article, we’ll explain everything homeowners need to know about power surges, especially those living in areas like San Francisco where urban infrastructure and coastal weather collide.
What Is a Power Surge?
A power surge is a sudden spike in electrical current that flows through your home’s wiring. It lasts for only a fraction of a second but can send the voltage on your power lines far beyond what your devices are designed to handle.
While most household electronics operate at 120 volts in the U.S., a power surge can push that number up dramatically—causing internal components to overheat or short-circuit. When multiple surges happen over time, they can cause power degradation that leads to premature failure of computers, televisions, HVAC systems, and other connected equipment.
Common Causes of Power Surges in San Francisco Homes
Living in San Francisco, you’re part of a dense, aging power grid. While the city has made strides in modernizing its power supply, there are still several factors that can cause a power surge unexpectedly.
Some of the most common causes of power surges include:
- Lightning Strikes: Though rare, lightning can send millions of volts into the ground. If your home’s wiring isn’t properly protected, this can result in major power surge damage.
- Utility Grid Switching: The local utility provider frequently re-routes power to handle load changes. These switches can result in surges, especially when power is suddenly restored after an outage.
- Downed Power Lines: During storms or accidents, fallen lines can create erratic voltage on your power line—often creating a backfeed of energy into nearby homes.
- High-Energy Appliances: Devices like refrigerators, air conditioners, and washing machines can trigger internal power surges when they start up or shut down suddenly.
Understanding what causes power surges—and how they interact with your home—is essential if you’re trying to diagnose why your lights flicker, your electronics wear out quickly, or your circuit breaker trips randomly.
What Power Surges Cause: A Closer Look at the Damage
It’s easy to underestimate how much damage a power surge can do, especially when the effects aren’t always immediate. But power surge damage is often cumulative and difficult to reverse.
Here are a few examples of what power surges cause in San Francisco homes:
- Corrupted Electronics: A short burst of high voltage can cause power to fry delicate circuits inside computers, routers, and smart devices.
- Worn Circuit Boards: Repeated electrical surge exposure wears down internal boards over time—even if the device continues to function.
- Tripped Circuit Breakers: Circuit breakers, designed to protect your wiring, may trip if a power surge is significant enough—leaving you to lose power temporarily or worse, deal with repeated disruptions.
Even homes in newly developed parts of San Francisco can be vulnerable if they’re connected to the same power grid as older neighborhoods with less-stable infrastructure.
External Power Surges vs. Internal Power Surges
Not all surges are created equal. There are two main types of power surges that can affect your home: external and internal.
External Power Surges
These originate from outside your home—usually from the utility company or the power grid itself. Examples include lightning strikes, transformer malfunctions, and grid switching events. They tend to be stronger and can cause power damage across multiple circuits or homes.
Internal Power Surges
These happen inside your home, usually triggered by large appliances cycling on and off. For example, when your refrigerator’s compressor starts or your air conditioner shuts down, it can send a jolt back through your home’s power systems.
While smaller than external surges, repeated internal power surges still pose a serious threat—especially to sensitive electronics and smart home equipment.
What Causes Power Surges in New vs. Older San Francisco Homes?
Older homes in San Francisco—especially those with outdated wiring or overloaded panels—are more likely to experience power surge issues due to:
- Faulty wiring that can’t handle sudden current shifts
- Aging circuit breakers that fail to trip when needed
- Lack of modern surge protection at the electrical service panel
However, newer homes aren’t immune either. Builders sometimes focus on energy efficiency without including adequate surge suppression at the main panel, leaving smart appliances exposed.
In both cases, the key is understanding how power surges cause electrical instability, and how those surges behave differently depending on your home’s design and condition.
How Do Power Surges Relate to Power Outages?
While a power outage might seem like the opposite of a power surge, they’re often connected. When utilities restore power after an outage, a surge of electricity can rush into your home all at once—especially if multiple homes are reconnected simultaneously.
This sudden influx can damage your electronics even more than the initial power outage itself. That’s why power surge damage often happens during storm recovery or during rolling blackouts, which occasionally occur during high-demand seasons in San Francisco.
If you’ve ever lost power and noticed problems with your electronics after things come back on, you’ve probably experienced a surge.
Why San Francisco Homeowners Trust Wisdom Electrical
At Wisdom Electrical, we’ve seen firsthand how power surges can impact homes across San Francisco—from older buildings with aging infrastructure to modern residences packed with smart technology. Our team takes a thoughtful, detail-oriented approach to electrical safety, helping you understand what’s happening behind your walls and what to watch out for.
We don’t believe in guesswork. When we assess your power systems, we look beyond the surface to uncover the real cause of flickering lights, tripping breakers, or unexpected equipment failures. If you’re seeing signs of recurring power surge damage, we’re here to help you make sense of it—clearly, professionally, and without overcomplicating things.
Final Thoughts
While you can’t prevent every power surge, understanding the causes of power surges helps you stay alert to signs of damage and instability. Whether you live in an old Victorian in the Richmond or a modern condo downtown, your power supply is subject to changes beyond your control—both internally and externally.
