Is bigger better when it comes to kA ratings?
Yes and no. When dealing with surge protection there are two main areas where this kA argument comes into play and that is at the main service entrance and at any branch panel down line of the main service entrance. When deciding what kA rating to install keep these four things in mind: cost, space, and consider transient factors i.e. is it a high lightning area, does the factory next door put a lot of transients on the line? Starting with cost keep in mind that usually a higher kA rating costs more money. You may be buying extra protection that is not needed. Then there’s space and weight. More kA generally means you’re buying something larger. This might be taking up valuable space that is needed by something else. Lastly, there are the transients themselves. IEEE suggests that most transients entering a service entrance are less than 10 kA.
