Now here is the trick to the entire install. The switch has a indicator 
light that will light when power is applied to the water heater. When 
the switch is off, power is shut off to the water heater but the 
receptacle remains hot at all times. With this receptacle you can 
plug an additional heater into it and PRESTO you have a camper 
with 3 heaters to keep you warm even in 15 degree weather !!! My 
first test the outside temperature got down to 18 degrees and with 
the heaters I had no trouble keeping the camper at a very comfortable 
72 degrees !!! Yes , it does get cold in North Carolina!! If you don't 
believe it just check out our photo album under North Carolina 
weather. 2 feet of snow and a low temperature of 2 degrees!!