Leviton 51120-1 Surge Suppressor Review

Leviton 51120-1 In this Leviton 51120-1 review we are going to cover the most critical information you need to know about this whole house surge protector device.

This SPD started getting some attention around 2010 – 2011 and right now it’s been getting some consumer reviews over the internet. Are those good reviews or not so good reviews? In this article we’re going to break down the important factors to consider with this surge protector.


There are 4 types of surge protection that are available and the Leviton 51120-1 panel surge suppressor is categorized as a type-2 SPD. What this means is that a type-2 SPD is to be installed in your main breaker panel. These devices can give you protection from indirect lightning strikes, high voltage spikes and some crazy transient voltage.

The protection panel is built for single phase applications in homes at the service entrance and this is also ideal for light commercial structures.

Here’s a quick glance of what you can expect with the Leviton 51120-1:

  • Solid state suppression per phase
  • Real time visual indicator for surge protection status
  • Standard j box enclosure
  • Low VPR for protecting sensitive electronics
  • Compatible with Leviton Decora home controls
  • Limited lifetime warranty
  • Connected equipment coverage up to $25,000

Leviton 51120-1 Installation

If you have some electrical experience, the Leviton is going to be fairly easy to install as the instructions are pretty clear. If you need some detailed instructions to gauge the complexity of the installation before you purchase, then simply head over to Leviton’s website.

Take note that this surge protector needs 4 wires for the installation but those wires are not going to be included in your purchase.

As for the wires, you will need 2 black wires which are going to be for the 2 hot electric buses. A white one for the neutral connection and a green one for the ground. Any wire with a minimum of 12 gauge can be used if you’re going to connect it to a 20amp breaker.

The average installation time is going to be around 30 minutes and this is the time from cutting your power off to restoring it. You will have to add in a 20amp double pole circuit breaker to your main breaker panel.

It’s critical that you call your local licensed electrician if you don’t have any experience or if you’re not comfortable working with a breaker panel.

It’s not my intention to scare you but there are hot points inside your breaker that can kill you if you don’t know what you’re doing. There are many videos online that will show you how to install a type-2 SPD but only use those videos as your reference and get some information from it so you could relay it to your electrician.

The Leviton 51120-1 comes in a J-Box metal NEMA type-1 enclosure. This type of enclosure is rated by NEMA to be used for general purpose and also for indoor use. It will provide you with some protection from electrically charged live parts and it will also protect the device from foreign objects like dirt and accumulated dust.

Up to Standards?

The Leviton 51120-1 surge protector has been designed according to standards and it’s fully compliant with the UL 1449 3rd edition.

What’s the UL 1449? Basically it’s all about the safety and performance standards of surge protection devices by the Underwriters Laboratories. This was revised to a 3rd edition back in 2009 and there were 2 critical objectives of the revision.

First objective is to make sure that there is compliance with the international standards for surge protection. The next objective is to change the performance testing methods to better simulate real world scenarios.

Surge Protector Consumers Win!

The changes in the 3rd edition now give 3 significant improvements for consumers of SPDs.

The first is the addition of type-1, also known as secondary surge arresters, which are typically installed outdoors and right before the service entrance equipment.

The second improvement is the addition of a new statistic called the Nominal Discharge Current Rating. As a consumer, this means that you’ll be able to compare a surge suppressor’s durability (or the capacity to survive a lightning strike) under a regulated test of the Underwriters Laboratories.

With that being said, the Leviton 51120-1 has a nominal discharge current rating of 3kA.

The third beneficial change is all about the Voltage Protection Rating (VPR). Before this improvement, this was called the Surge Voltage Rating (SVR) and its procedures were really weak to test out many of the SPDs in a way that would show how well their performance really is.

Real Time Visual Indicator

This device will have 2 lights that will indicate its status. Obviously you want to see the green light as much as possible because this means that your device is perfectly running and ready to protect. A red light means that the device encountered a surge and that you have to replace it and get a new surge protector.

Leviton 51120-1 Price

If you’re going to do some research, you will find out the Leviton 51120-1 is going to be more expensive than the other whole house surge protectors. However, you will also find out that they have the highest specifications when it comes to surge suppression for single phase residential use.

If your local power utility installs a whole house surge protector and includes a $10 per month in your electricity bill, then the Leviton 51120-1 will pay for itself in more or less 20 months.


The Leviton 51120-1 provides a limited lifetime warranty and if you want more information on their warranty, there’s a file you can easily download at their product page.

They also provide connected equipment coverage of up to $25,000. But like most of the surge suppression businesses around, you’re going to go through a very lengthy process of claiming your coverage and you might not even get a full 100% of your claim.

As for Leviton’s coverage, any outdoor equipment is not going to be covered. I advice that you carefully read the coverage of your warranty and it’s up to you whether it’s worth it to argue with them on what’s covered and what’s not.

What’s Next?

Hopefully this review helped you when it comes to making a decision with this surge protector. Do you have any experience with the Leviton 51120-1 surge suppressor? Leave your comments below.

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