Whole-Home Surge Protection

A surge is a brief spike in voltage. Long enough to punch through the insulation inside a control board, short enough that nothing else in the house reacts. Homeowners tend to picture lightning, and lightning does contribute, but the routine damage comes from somewhere less dramatic.

Distribution circuits out here use reclosers, which open and reclose in quick succession when a fault clears itself, which is exactly what happens when a branch comes off a tree or a bird finds the wrong two conductors. Capacitor banks switch to hold voltage on hot afternoons. And the single roughest moment on any circuit is power returning after an outage, when load reconnects all at once across a whole neighborhood.

Inside the house, your own equipment adds to it. Every time a well pump, a compressor or a refrigeration unit shuts off, the collapsing magnetic field puts a spike back on the wiring. None of these individually destroys anything. Cumulatively, they are why a variable-speed HVAC control board fails at year six instead of year fifteen.

The reason you need more than one is physics rather than salesmanship. A device sized to absorb a large event cannot also clamp tightly, so it lets a residual voltage through, and that residual is still well above what a sensitive circuit board wants to see. The service-entrance device handles the magnitude. The point-of-use device handles the precision. Together they get the let-through voltage down to something the equipment can live with.

Recent editions of the National Electrical Code require surge protection on new and replaced dwelling services, so if you are already looking at a panel or service upgrade, a device at the service entrance is part of that work rather than an extra.

When people picture surge damage they picture a television. In practice the expensive failures are the hardwired equipment, which is exactly what a plug-in strip cannot help with:

• Variable-speed HVAC control boards and communicating thermostats
• Well pump controllers and constant-pressure drives, which are not cheap and are not quick to source
• Solar inverters and microinverters, and battery system electronics
• Generator controllers, transfer switch logic and monitoring modules
• Appliance control boards in ranges, ovens, refrigerators and washers
• Garage door openers, irrigation controllers, gate operators and pool equipment
• Network equipment, security systems and anything with a permanent power supply

On a rural property, the well pump alone justifies the conversation. If you also have a solar array or battery storage, there is a meaningful amount of electronics hanging off that service, and none of it is plugged into anything you could put a strip on.

A direct lightning strike to the structure is beyond what any service-entrance device is rated to absorb. Nothing at your panel changes that, and any contractor telling you otherwise is describing a product that does not exist. What protection handles well is induced energy from nearby strikes and the switching transients that make up the overwhelming majority of real events.

Protective devices also wear out. They absorb energy and degrade doing it, which is why quality equipment has a status indicator on the front. A device installed in 2019 that has taken a few hard events may be doing nothing at all today. Checking it takes ten seconds, and it is part of every maintenance visit we make.

And protection is not a substitute for the rest of the electrical system being sound. Poor grounding, loose terminations and a panel at the end of its life will undermine a good device. We look at those first, because a protector bolted onto a bad service is decoration.