Whole house surge protectors provide a first line of defense against electrical damage

For several years now, homeowners have been advised to get surge protectors to safeguard their expensive items. By simply fitting a surge protector into an electrical outlet before plugging a device in, you can ensure that your computer, television, or other electronics won't be fried by a sudden spike in energy.

Unfortunately, it isn't quite that simple. While some of your devices may be plugged into surge protectors, many are likely unguarded. If you have a laptop computer, you may opt for the convenience of plugging into any available outlet instead of hunting for one with a surge protector. Donna Boyle Schwartz, writing for the home improvement professional Bob Vila, says some items may be hardwired into the electrical system instead of plugged into outlets.

Moreover, a power surge will likely affect more than just your traditional electronics. Family Handyman notes that many newer items, ranging from appliances to exercise equipment, will have circuit boards that can be knocked out by a surge. The replacement cost for the circuit board may be high enough that it simply makes more sense to replace the entire item, at considerable expense.

For these reasons, a whole house surge protector can be a useful way to protect your home from electrical spikes. The National Electrical Code for 2020 has advised that this feature be included in all new homes and added to existing homes when the service panel is updated.

A lightning strike is the most dramatic example of a power surge, but other more commonplace incidents can also cause surges. Jim Collins, writing for This Old House, says damaging power fluctuations are more likely to be caused by things like power cycling of devices within the home, substantial changes in energy use at a nearby facility, or a downed power line.

The surges caused by these incidents are not as severe as a lightning strike, so they may not be enough to burn out an item. However, they can still shorten the lifespan of your electronics and appliances.

A whole house surge protector is installed on the service panel to protect against energy fluctuations on the power line into your home. Since power surges can also enter the home through other cables—such as phone, cable, and Internet lines—Family Handyman says a whole house surge protector or separate surge protectors should ideally protect these as well.

The surge protector typically allows electricity to flow as usual into the home. Collins says that when a spike in voltage is detected, the surge protector acts quickly to safely direct the excess energy into a grounding wire and away from the home's electrical system.

Check to see how large of a power surge a whole house surge protector is able to take. Family Handyman says some inexpensive models may only be able to divert surges of 10,000 amps or less; while this can be helpful for smaller surges, it will be knocked out by a larger one. A surge protector with a rating of 40,000 to 50,000 amps is ideal.

You should also see if the surge protector has features to alert you when a power surge has happened. Schwartz says some surge protectors have modules which trigger a light when they need to be replaced; a homeowner can easily swap out the module when necessary to allow the surge protector to continue working well.

Unless you have experience working with electrical systems, leave the installation of a whole house surge protector to a professional electrician. Family Handyman says the service panel will have dangerous live wires even if the main breaker has been shut down, so installing the device on the panel will be hazardous if you don't know which areas you need to avoid.

While a whole house surge protector can provide some peace of mind, it shouldn't be your only method of protection against power surges. Collins says about 15 percent of the energy in any surge may not be diverted at the service panel. George Brazil Plumbing & Electrical, an Arizona company, says these smaller surges can still be powerful enough to damage electronics.

You can check the voltage protection rating of the whole house surge protector to see