I have two, not one, rotary dials on my AC panel. They are labeled the same. My guess is that they permit you to split the AC load on the boat when using two 50 amp cords. However, they are not labeled for which cord is which. Any idea why mine has two dials and the book shows only one? And, can you split thevAC load somehow if using only one 50 amp cord? It's on a 2001 56 SS.