Hi there, The above posts about a surge protector are correct, don't plug in without one. They also protect from under voltage. It's cheap insurance. There are hundreds of post in this site about them. Nobody disagrees about having one, they just tend to squabble about which is best. Doesn't really matter, the worst is not having one.
You didn't indicate what amperage of park post you wanted to test. However, if you want to check 50 Amp posts check out this link.
Hope this helps,