Here the safety switch has been installed along with its wiring. Note the use of clips to keep the wiring neat and out of the way while working. Notice also that the electrical box is outside of the sanding box where it cannot cause a dust explosion. I used 12 ga. wire all the way. My father, an electrical engineer, taught me that you can never be too safe. He was a firm believer in using 12 ga. wire even when 14 ga. would do. The additional cost is negligible.
I bought the safety switch from Grizzly. I had a wee bit of a problem finding a box that it would fit on neatly. I ended up buying a water-proof box. I found it in the irrigation section of Home Depot. It looks good to me :-)