I have been brewing for many years and started a full electric (Kal clone) build over two years ago. The project was initiated just before we found out my wife was pregnant with twin girls. (just in case anyone wanted to know a set of twins will go through more than 5000 diapers in a year, I also determined that they conspire together to sleep on different schedules). 18 months later and with the help of some great ADD medication I have finally taken the last steps to finish. I completed the control panel last night, with the exception of the key switch that I broke the housing on. This should be arriving today or tomorrow and I will be ready to power it up. I picked up a Sanke for the MLT and cut the bottom out over the weekend. I set up the table to drain the sanke through the keg neck into a 2" - 1.5" tri-clover reducer. The Sanke HLT w stainless coil, Boil kettle, rolling table, pumps and cooler were all completed before the hiatus. If all goes well with the CP I hope to do a water test this weekend.
The big red turn switch was on the box when I bought it. I modified the layout around the switch and the few holes that were already cut in the box. The same goes for the inside where the internal side of the switch was located and the rails. It is a cool switch as it locks the door shut when in the on position.
But you are correct. It is a emergency power off. Throwing the switch cuts both hots on the 220 line.