How to install a water heater timer.   

Page 1 of 3: Gather materials

Gather materials:

Step 2.) Buy old-work box at hardware store or home center.

Step 3.) Buy H230B or 45EG20AF contactor with 
120Volt coil and 30 amp contacts: Timer turns magnetic coil on-off, coil opens and closes contacts that turn electricity on-off.

Available at Heat/AC supply or electric supply or internet.

Buy H230B at CSH

Each water heater requires separate contactor

Step 4.) Buy 6x6x4 enclosure: 

Carlon box shown is easy to drill: Buy at Home Depot or Lowes

Step 5.) Buy cut lengths of 10-2 with ground and 14-2 with ground: 

Available at hardware store and home center.