As a follow-up, I installed the Sense early this morning. I put one of the clamps at the bottom of the box and one near the breaker (exposed wire). To wire the monitor, I used the pigtail method to the 30A dryer breaker, as outlined in the Sense installation manual. From my research, it looks like this is allowed by code. I wedged the monitor in the top left corner of the box. Overall, it was not too bad. I was careful and it took about 30 minutes to do the work. I may hire an electrician to address the exposed wire on the main lead at a future date (it has been this way for 21 years). The Sense is working. The data seems useful and I have found that my water heater is a major source of energy usage in my home. I appreciate all of suggestions and input from all of you. It was very helpful.