Surge Arrestor in Panels

First, consider that the word "surge" is more than one type of problem. Next, you need to consider whether to arrest it or resist it. The answers indicate different solutions.

Taking all of this into account will help you decide what money to spend, if any. It may be overkill or under-protect if you make the right choice. And then, you may have to consider liability if you make the wrong choice.

If the building is going to be used to make fertilizer (or other potential explosives) there are most likely codes that you must follow. So, building use is a big factor in making the right decision. The type of equipment that will be in the building is also a big consideration. You may have to read the manufacturers recommendations or make some personal contacts.

The kind of surge protection that the power company provides generally takes care of problems like a lightning strike. This is because a lightning strike will frequently ionize the air between distribution lines causing a short that persists after the bolt of lightning disappears. When that happens, the current flow must be interrupted long enough to allow the ionized air to dissipate. That may cause a blackout that lasts for up to 1 second.

A blackout is not a surge, although many people throw this term around as if it were. For a blackout, you need a UPS (uninterpretable power supply) big enough and fast enough to keep your power going. A UPS generally also has other surge protection devices built into it.

If you are near an industrial area, you may have high frequency noise on your power line that is considered to be a surge. In that case, a "line reactor" is usually the best choice. But a line reactor will not prevent an over-voltage from destroying your equipment. For that, a surge arrestor with metal oxide varistors will help but only if they are installed properly.

So, perhaps you can now see why everyone is suggesting all of these links to rules and professionals. It really depends on where you are and what you are facing. And just because you "solve" the problem today, don't think that you are finished. This is because you will always have neighbors who connect to the same power lines. And you may have to protect your building from things like welding noise on the line.

It is a little like buying insurance. You never quite know if you have enough until you need it.