EZSMART Corporation, ESA/ECRA #7012690 , North York , Ontario
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Flickering lights, appliances that suddenly reset, and prematurely fried electronics can all trace back to the same culprit. Understanding what causes a power surge in a home is the first step to protecting your gear and preventing fire hazards. The good news: most surges are preventable once you know where they come from.
A power surge is any spike in electrical voltage above the standard 120 volts that Canadian homes are wired to receive. Some surges last a fraction of a millisecond and cause no visible damage, while others can hit 6,000 volts and destroy electronics instantly. Either way, the damage adds up over time.
Power surges come from two directions: outside the home (external surges) and inside your walls (internal surges). External sources include lightning strikes on or near power lines, utility grid switching, downed lines, and tree branches contacting overhead wires during storms.
Internal sources — the ones most homeowners overlook — include high-draw appliances cycling on and off, faulty or aging wiring, loose electrical connections, and overloaded circuits. Refrigerators, air conditioners, dryers, and even microwaves send small voltage bumps back through your wiring every time their motors kick on.
The Electrical Safety Foundation International (ESFI) estimates that 60 to 80 percent of power surges originate inside the home from appliances cycling on and off. These smaller repeated surges rarely destroy anything on the spot, but they degrade sensitive electronics — TVs, computers, LED drivers, and smart-home hubs — over months and years.
A single lightning strike can be catastrophic, but internal microsurges are what quietly shorten the lifespan of everything plugged into your walls.
The gold standard is layered protection. Start with a whole-home surge protector installed at your electrical panel — it clamps large external surges before they reach your outlets. Then add point-of-use surge protectors (not just power strips) at your entertainment centre, home office, and kitchen counter for smaller internal surges.
Also worth doing: unplug expensive electronics during major thunderstorms, replace any surge protector older than 5–7 years, and have an electrician inspect your panel if you notice frequent flickering or nuisance breaker trips. If your power keeps blipping on and off, that is often a sign of a bigger utility or panel issue driving surges.
In our experience wiring homes across the GTA, the surges that actually kill electronics are not lightning strikes — they are the daily microsurges from a fridge compressor or central AC on the same panel as your TV and computer. A whole-home surge protector installed at the panel is cheaper than replacing a single 65-inch OLED, and it typically lasts 8–10 years. If your home was built before 2000 and still uses the original panel, this is one of the highest-value upgrades you can make.
Have questions about power surges or ready to install whole-home surge protection? Call us at 416-838-9006 or visit our contact page — we will be happy to help.
