This standard establishes the maximum envelope dimensions and nominal mounting dimensions for encapsulated transformers and inductors using cores listed in Table I of EIA Standard RS-217-A. This standard also establishes formulae from which these dimensions are developed.

For the purposes of this standard, encapsulated units shall be those which are either dipped, conformally coated, cast, embedded, molded, encased, impregnated, filled or otherwise protected with a non-metallic substance.