49 C.F.R. § 195.565
After October 2, 2000, when you install cathodic protection under § 195.563(a) to protect the bottom of an aboveground breakout tank of more than 500 barrels 79.49m3 capacity built to API Spec 12F (incorporated by reference, see§ 195.3 ), API Std 620 (incorporated by reference, see§ 195.3 ), API Std 650 (incorporated by reference, see§ 195.3 ), or API Std 650's predecessor, Standard 12C, you must install the system in accordance with API RP 651 (incorporated by reference, see§ 195.3 ). However, you don't need to comply with API RP 651 when installing any tank for which you note in the corrosion control procedures established under § 195.402(c)(3) why complying with all or certain provisions of API RP 651 is not necessary for the safety of the tank.
49 C.F.R. §195.565