Is it useful to invest in and have a whole home surge suppressor installed at my inside and outside panels. My home was built 2 months ago. Home do I install the whole home surge suppressor and what should be cautious of. Will the whole home surge suppressors cause problems with any of my devices in the house?

  • Depends what equipment you have that would be vulnerable to surges, and what other equipment you have that will make surges. That's right, with surges your worst enemy can be your own stuff. Jun 15, 2018 at 16:13
  • It's not always necessary to have whole home surge protectors. I live in an area that has very reliable power, buried power lines, and few lightning storms. I don't feel like I need one. But, I might feel differently if I lived somewhere else.
    – mrog
    Jun 15, 2018 at 16:16
  • I have added whole home supressors on quite a few homes that were experianceing problems from spikes from an industrial facility (a lumbermill in this area) the larger units do a great job of dumping line spikes to ground. Most of the units I have installed require a 30 amp double pole breaker or larger in the main panel or adjacent to it for best results. They do need to be checked as when they do there job on very large spikes protecting your home they can be damaged most have lights to show if they are working or need repair replacement.
    – Ed Beal
    Jun 15, 2018 at 17:08

2 Answers 2


The IEEE develops standards for surge protection devices (SPDs). Curious electrical engineers in the audience can read their “trilogy” on the subject. For the average DIYer I recommend this much simpler presentation.

Two important points come out of these materials. (1) No SPD shunts all of the transient energy. (2) The further the appliance from the SPD the higher the transient voltage spike. Therefore, to get the best protection cascade SPD devices.

It’s not true that using plug-in Type 3 SPDs around your house gives you full protection. Hard-wired appliances will be unprotected and most plug-in units can handle only a limited amount of energy. It’s also not correct to say that once you have a whole-house SPD you can toss the plug-in units. Unless your home is a one-room cabin your sensitive appliances will be many meters from the SPD at your service panel.

There are several answers to related questions on DIYSE that should help you pick out and install a whole house unit. See for example this answer.

In a typical home you should use a suitably sized Type 2 SPD installed on the load side of your service panel supplemented by plug-in Type 3 SPDs for sensitive electronics within the home.

If you are in a lightning prone area and the AC compressor or other outside equipment is far from the service panel it may make sense to install a supplementary Type 2 SPD at the local disconnect for this unit. For most homeowners this is overkill.

Unless you live in an area that is prone to lightning AND have a lightning protection system installed then it is unlikely you can take advantage of a Type 1 surge suppressor (installs on meter side of your service panel). You will get the same protection from a Type 2 unit at a lower installed cost.


A whole-house surge protector is used for the same reasons that you use the power-strip surge protectors with your computers and TVs - to protect that equipment from power surges. The benefit of a whole-house unit, though, is that it protects everything connected to your electrical panel - your furnace, AC, water heater (if electric), washing machine, as well as your computers and TVs. Newer appliances have a lot of internal electronics, and the cost of replacing a fried circuit board can exceed the cost of a new appliance, making the installation of a whole-house surge protector a very attractive value.

Be sure to read the fine print of any warranty the surge protector comes with, as it may require professional installation. Typically, these units come as a double-pole breaker and are usually installed as one of the first breakers in the panel. Some of them have also a piece that sits outside the panel, and are installed through a knockout in the panel.

A lot of people will tell you to continue using strip surge protectors for your consumer electronics, and there really is no harm. Most of us need the extra outlets provided by the power strip anyway.

  • 1
    Power strip surge suppression is pretty much rubbish anyway, it uses the cheapest possible way to suppress, which is ablative and quickly is consumed. Jun 15, 2018 at 18:51
  • @Harper -- most Type 2 SPDs are MOV based as well; however, they're better thought out (with loss-of-protection indications) than most Type 3 units are Jun 16, 2018 at 4:05

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