This paper will discuss the key applicable North American Standards defining performance, testing, installation and routine field maintenance of liquid-immersed distribution substation transformers. These transformers, typically applied in commercial and industrial power systems, can be installed either in outdoor or indoor locations, applied as remote or close-coupled to either primary or secondary switchgear, or both. Recommendations based on these standards for selection, installation and factory/field testing industry users should specify to maximize reliability, operational efficiency and safety will follow.