My family an I are patiently waiting for the completion of our home - construction is due to finish the end of this month. One of the garage spaces is called an "RV" spot, and I see that the builder has included a 220 volt outlet, presumably for some sort of RV hookup. We have no RV but my eye is on this large space is not for parking, but for my new workshop - wahoo!

Anyway, I had sold my old Craftsman contractor saw when we left California and the wife said I can buy a new table saw (wahoo #2!). My wish/plan is the 3 HP, 220 volt Sawstop PCS. Looking at the Sawstop web site, it appears that the saw will come with a NEMA 6-15P plug (round ground prong and two flat horizontal hot / neutral? prongs). Well, the outlet the builder has installed has FOUR holes in it: one round ground plug at the bottom, two flat 45 degree holes on the sides, and one flat horizontal hole at the top).

Worst (best?) case would be to have an electrician re-do it but if this is something simple that I can change out I'd sooner do it myself. However, I don't want the new saw to turn into a large flaming mass, either.

I am not familiar with 220 volt plugs or receptacles - can anyone here venture an educated guess as to what the heck sort of outlet this is? I know that the Sawstop manual describes how to replace the supplied cable with one of your choice, but what the heck is that fourth hole for on the outlet?

Thanks, Jim