How Does a Whole House Surge Protector Work?

By John Adebimitan

In this article, you’ll be getting answers to questions and queries such as How Does a Whole House Surge Protector Work? how to install a whole-house surge protector, how whole-house surge protectors work, and the pros and cons of whole house surge protectors.

First, let’s talk about what surge protectors are, their purpose, and how you can benefit from installing them in your homes.

How does a whole house surge protector work?

So how does a surge protector work? A whole-house surge protector comes with a device inside that will create a low-impedance path to the earth whenever the voltage in the circuit goes beyond a threshold.

The device stays pretty long and rarely gets damaged because the surge doesn’t last for long. It’s like a spike; after a few microseconds, it returns to normal.

It also comes with a fuse, which will protect the circuit whenever the device is overloaded or when the spike is repeated over a longer period.

When used in the whole house, it kind of gives you that same protection, but this time, it protects every electrical appliance, electronic, and lighting point in the house.

How Does a Whole House Surge Protector Work?

Are there pros and cons of whole house surge protectors? Well, yes, but let’s first talk about the whole house surge protector cost.

Read also: Best Power Strips with Long Cords and a Surge Protector

Surge protector cost

So how much do you think a surge protector will cost? On average, we have found that a whole house surge protector will cost between $300 and $500.

If you don’t have experience installing the whole house surge protector, you’d need to get an electrician who might also charge starting from $150 for one installation. This installation often includes protection for all your electronics and equipment in your home.

How Does a Whole House Surge Protector Work?

Pros and cons of whole house surge protector


  • The best defense against power spikes and surges.
  • Protects your investment. You have undoubtedly spent a lot on your appliances and electronics, so having something to keep them safe is a great investment for everyone.


  • While they are greatly useful, it’s been found that around 15 percent of excess voltage still escapes through. So don’t stop using your power strip surge protectors even after you have installed the whole house surge protector.
  • Installation is expensive, sometimes going as high as half the purchase price of the surge protector.

Best whole house surge protectors

I thought you’d need help in choosing the best surge protector. I have included a list of my hand-picked selection of the best whole-house surge protectors and some of their key features. Feel free to comment on which of them suits your needs most.

ProductRatingWhere to Find
Siemens FS140 Surge Protector6″ x 10″ x 4″, 120/240V, 140kACheck On Amazon
Eaton CHSPT2ULTRA120V / 240V, 108kACheck On Amazon
Leviton 51120 Surge Protector14.4″ x 8.4″ x 6.9″, 120/240V, 60kACheck On Amazon
Schneider Electric HEPD802.7″ x 3.8″ x 3.6″, 120/240V, 80kACheck On Amazon

Installing a whole house surge protector

Surge protector installation isn’t rocket science; with some electrical tools like pliers, cable strippers, screwdrivers and screws, flashlights, hammers, and nails, you should have all you need to start your surge protector installation.

While the process is simple, it’s recommended that you get an electrician to do the job for you, especially when you don’t have any electrical experience.

Here is a pretty easy-to-follow video on how to install whole-house surge protectors that should help you handle your whole-house surge protector installation like a pro:

YouTube video

Types of Whole House Surge Protectors

The most common way to distinguish the surge protector type is to look at the front panel where you should see the markings T1, T2, or T3.

Some manufacturers and installers use the old terminology and refer to these surge protectors as class B, C or D. However, these names are incompatible with the above standard.

Type 1 whole house surge protector

Type 1 (T1) surge protectors are designed to discharge high power surge currents with a 10/350 μs waveform.

This high power surge is often caused by lightning strikes in power supply networks, the so-called overhead lines.

These lightning current protectors are installed after the first short-circuit protection device, directly behind the electricity meter (in the main switchgear).

Their task is to limit the voltage pulse to a value below 4 kV; most manufacturers indicate the value reached as 2.5 kV.

Type 2 whole-house surge protector

Type 2 surge protectors are designed to divert overvoltages caused by switching operations in the circuit (waveform 8/20 μs).

These surge protectors are to be installed behind main distributors (which also contain type 1 surge protectors) in sub-distributors (in multi-family houses in distributors for individual apartments).

The task of type 2 surge protectors is to limit the overvoltage to the value of 1-1.5 kV. It protects a large part of the electrical equipment from switching and overvoltages discharged by type 1 surge protectors but endangers many devices.

To ensure proper operation, the cable length between type 1 and type 2 surge protectors should be at least 10 m.

Type 3 whole-house surge protector

Type 3 surge protectors are used for local protection. This means they are best installed as close as possible to the equipment to be protected.

They perform the function of secondary lightning protection while limiting voltage spikes caused by switching in the network.

They also prevent overvoltage disturbances from reaching electronic devices via the power supply lines, which can lead to their damage.

Using only this level of protection does not guarantee complete surge protection for the device.

Combined surge protectors

There are also “combined” surge protectors on the market, i.e., combinations of type 1 and 2. An example is the KSD-T1+T2 275/60 1P surge protector, which has T1/T2 surge protectors.

With appropriate dimensioning, they are also suitable for use in photovoltaic systems. Type 1+2 surge protectors are typically used in installations where the distance between type 1 and 2 devices (minimum 10 m) cannot be maintained.

Do Whole-House Surge Protectors Work Against Lightning?

While most surge protectors (especially T1 types) can protect against lightning (or are supposed to), it depends on the device’s capacity. For example, a flash of lightning can reach 300 million Volts or 30,000 Amps. Meanwhile, most surge protectors cannot hold any more than 500 volts.

So, do not confuse surge protectors or lightning protectors with lightning conductors. In addition, unplugging all main electrical appliances from the mains is safer during the rain.

As we have just seen, the surge protector is a device installed on the electrical panel of a dwelling. It protects the installation and the electrical appliances connected to it from overvoltage. On the other hand, a lightning rod is used to protect the frame, that is, the house’s structure or the building for which it is installed.

When the lightning strikes the lightning rod, the strong electrical intensity is sent directly to the ground. But when the lightning flash gets to the protectors, it will be too powerful for the installation.

So it’s always better to install a lightning rod and a surge protector.

The role of the lightning rod is not to attract the lightning towards it but to collect it when it is in a close radius. This, therefore, prevents it from coming inside the building and causing damage.

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