EZSMART Corporation, ESA/ECRA #7012690 , North York , Ontario
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Losing power during a rainstorm is usually caused by moisture infiltrating your home’s electrical service entrance, damaged outdoor wiring, or a “ground fault” occurring in external fixtures. When water bridges the gap between electrical components that should be insulated, it creates a short circuit that trips your breaker or blows a fuse to prevent a fire.
This guide explores the common reasons for weather-related power loss and how to identify the source.
The weatherhead is the hooded pipe on your roof where the utility company’s power lines connect to your home. If the rubber seals or “masthead” are old or cracked, rainwater can trickle down the service entrance cable and into your electrical panel.
The danger: When water reaches the panel, it creates a conductive path between your hot busbars and the grounded panel cabinet, causing an immediate short circuit.
The sign: If you notice power loss only during heavy rain or wind, it is highly likely that your service entrance cable jacket or the weatherhead seal has failed.
Outdoor outlets and light fixtures are required to be “weatherproof,” but seals wear out, gaskets dry-rot, and covers break over time.
Ground Fault Circuit Interrupters (GFCI): Modern outdoor outlets are protected by GFCIs. These are designed to detect even a tiny amount of electrical “leakage” caused by moisture. If water enters an outdoor box, the GFCI will trip to prevent a shock hazard.
Troubleshooting: If you lose power to specific outdoor areas when it rains, check your GFCI outlets inside or in the garage. If the “Reset” button is popped out, you have confirmed moisture is entering your external boxes.
If your home’s power is supplied by underground cables rather than overhead lines, shifting wet soil can sometimes expose or damage the protective conduit.
Water Infiltration: If the underground conduit has a crack, it can fill with water during heavy rain. This water can then track back into your electrical panel or meter base, causing an intermittent short.
Detection: This is difficult to diagnose without specialized equipment. If you notice lights flickering or power surges during rain, and your outdoor outlets appear fine, the issue may lie within the underground service feed.
Rain often comes with wind, and wind moves tree branches. Even if a branch doesn’t snap a power line, it can push wet limbs against your service lines.
Conductivity: Wet wood is significantly more conductive than dry wood. If a wet branch touches your service wires, it can cause “arcing” or a partial short, leading to light flickering or a full power outage as the utility transformer senses the fault and cuts power.
Safety: Never attempt to trim trees near utility service lines. Contact your local utility provider to report branches touching the power lines.
As a master electrician, I emphasize that electricity is very good at “tracking”—finding a path through moisture across surfaces that should be insulated. In my experience, if your power drops consistently during rain, your electrical system is giving you a clear warning before a total failure occurs. According to industry safety reports, recurring moisture-induced shorts significantly accelerate the corrosion of aluminum and copper terminals inside your panel. If you don’t address the entry point of the water, you are not just dealing with an annoyance; you are looking at a future repair bill for a melted or corroded main breaker panel.
Are you experiencing recurring power loss during storms or noticing flickering lights when the weather turns? Call us at 416-838-9006 or visit our contact page — we will be happy to help.
Electrician Since 2008 Journeyman Electrician Designated Master Electrician at EZSMART Corp
