Bare tanks and pipes at an average site containing three tanks will require about 4 amps or less for protection. Three coated tanks however, require 2 amps or less. The current output needed is affected by the amount of bare pipe, bare conduit and structural steel at the site. If one is unsure whether or not a site has STIP or bare steel tanks, the electrical resistance between tanks can provide the answer. A low resistance indicates the tanks are bare and not STIP. A high resistance over 100 ohms would indicate STIP tanks.