How Does a Whole House Surge Protector Work? A Guide to Surge Protectors

In this article, you’ll be getting answers to questions and queries such as how to install a whole house surge protector, how does a whole house surge protector work, best whole house surge protector, and the pros and cons of a whole house surge protector.

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

What is a surge protector?

So what is a surge protector? A surge protector is used to protect your home and all appliances in it from spikes in voltage. The surge protector limits the flow of the excess electrical current as it blocks any extra current flowing. The surge protector protects from lightening and smaller surges of electric currents that are caused by the electrical appliances in your home.

One of these types of surges is the one caused when you attempt to insert a two-pin plug into a three-pin socket. There are just so many smart appliances in our home these days, and many of them have been designed to consume the least amount of electrical power, so not having surge protectors installed could result in many of your appliances getting fried. So the purpose of a surge protector is to protect you from all types of electric spikes, no matter how little.

What is a power strip surge protector?

So there is a surge protector, and there is a power strip. A power strip is what many people will call an extension socket, which can be plugged into a wall, and it then offers ports in which you can plug other devices; in fact, these days there are USB power strips.

These power strips with USB ports have something like an inbuilt charger, so your devices don’t get damaged. You already know what a surge protector is. So what is a power strip surge protector?

power strip surge protector

A power strip surge protector is an extension socket that comes inbuilt with a surge protector. Not all power strips come with surge protectors, so how do you know those with surge protection?

The power strip surge protector would most likely have a “Protection” light that turns on when plugged into the wall socket. As long as the light comes on after plugging it into a power source, chances are that the surge protector is still working. You could also check the back of the power strip surge protector for any specifications that indicate surge protection. So you could see things like Suppression, Protection, Suppressed Voltage Rating, and many more.

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 circuited goes beyond a threshold. The reason why the device stays pretty long and rarely gets damaged is that the surge doesn’t last for long. It’s like a spike, after a few microseconds, it goes back 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-off gives you that same protection, but this time, it protects every electrical appliance, electronic and lighting points in the house. 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 with the installation of 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.

Pros and cons of whole house surge protector


  • The best defense against power spikes and surges.
  • Protects your investment. No doubt, you have 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

How to install whole house surge protector

Surge protector installation isn’t rocket science, with some electrical tools like plier, cable strippers, screwdrivers and screws, flashlight, hammer, 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 protector that should help you handle your whole house surge protector installation like a pro:

Pros and Cons of Whole House Surge Protector

Whole house surge protectors come with their benefits and downsides. Of course, the benefits outweigh the downsides but the latter borders on cost. Here’s a full analysis:


1.     Protects home appliances from power surges and brownouts

Whole house surge protectors help prevent electrical surges from damaging electrical devices and appliances in your home. In addition, they offer high protection from power surges and brownouts.

A surge protector protects devices in the event of lightning strikes, a transformer, or electricity generator overvoltage.

2.     Increases the durability of home appliances

A whole house surge protector protects your home and bank account as you’ll have fewer damaged appliances to replace. They increase the durability of your home appliances.

3.     They could earn you an insurance discount

Also, it’s worth noting that many insurance companies offer discounts for homes with surge protectors. Some could even punish you for not installing a power surge protector.


1.     It makes you over-reliant on them

After installing a whole house surge protector, some people feel it’s the be-all and end-all for household appliances’ safety. They think their devices are secure from high power surges such as lightning.

Unfortunately, large protectors will not always protect the home from a surge caused by a direct (or even a close) lightning strike. Unplugging devices from the outlet is the only way to provide 100% protection against lightning strike surges.

2.     They’re expensive

Surge protectors are more expensive than traditional surge strips. Most cost an average of $300 to install, while some installers can charge up to $700.

However, if you’re a good handyman, you can install it while spending just around $100.

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 types of surge protectors as class B, C or D. However, these names are incompatible with the above standard.

Type 1

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

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

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.

How Does a Panel Surge Protector Work

Surge protectors, also known as surge protective devices (SPD), are electrical protectors or voltage suppressors. During a sudden rise in voltage, the surge protector conducts the electric current directly to the ground, the earth.

It does not allow excess voltage into the electrical system so as not to damage the devices connected. They are designed to protect electrical devices from voltage spikes since they manage the electrical energy of an electronic device connected to them.

A surge protector regulates the voltage to an electrical device by blocking or grounding voltages above a safe threshold.

The general operation of a surge protector

Supposing that lightning strikes a few meters from an installation in a business or home environment. Then part of that voltaic charge from the lightning reaches the electrical installation.

Well, the surge protector consists of metal oxide varistors and dischargers. When the excess voltage reaches a specific voltage, the protector will drive that extra voltage to EARTH. This prevents the high voltage from reaching the equipment connected to the network.

When activating the protector, two things can happen. First, the integrated thermal magnet may trip, leaving the circuit in operation with the protector not melted. Then, all you have to do is reset it.

On the other hand, if the overvoltage is powerful enough, it could melt the protector. Therefore, it would have to be completely repaired.

How Do You Install a Surge Protector on a Panel?

  • Step 1: To start, switch off the general power supply and lower all the switches to the “Off” position.
  • Step 2: Unscrew the electrical panel cover. The surge protector must be installed at the level of the first safety module before the 30mA differential circuit breakers
  • Step 3: Unscrew the upper fixings of the differential switch present at the head of the line of the module,
  • Step 4: Remove the neutral and phase wires, making the connection with the subscriber circuit breaker
  • Step 5: Make a space for the installation of the protector by pushing the modules to the right
  • Step 6: Clip the surge protector in place of the differential switch and connect the phase and neutral wires. The blue wire, corresponding to the neutral, must be connected to the N terminal, the black phase wire to the L
  • Step 7: Fold the previously offset modules against the surge protector module
  • Step 8: Connect the differential switch with connection combs: insert the neutral connection comb on the neutral terminals of the surge protector and the differential. Then, in the same logic, the phase connection comb is inserted on the phase terminals of the two elements. The black comb should be placed in front of the blue. Finally, screw back the front.
  • Step 9: Connect the surge protector to the ground using a ground wire no more than 20 inches long. To do this, strip it at both ends. Then place it and screw it on the front of the earth terminal under the surge protector.
  • Step 10: Repeat by connecting the other end to the terminal block of the electrical panel,
  • Step 11: Replace the switchboard cover, taking care to remove a sufficient number of blanking plugs
  • Step 12: Restore power.

Tips and Warning

  • The surge protector must be installed on the main electrical panel of a building or apartment, equipped with a differential circuit breaker and a branch circuit breaker.
  • It must also be directly grounded. Even as a DIYer, installing a surge protector requires good knowledge of electricity.
  • Do not hesitate to contact a professional if you do not know about electricity.

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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