This standard applies to high-potential testing of complete excitation systems and their components for synchronous machines. The components of the excitation system are described in IEEE Std 421-1972, Criteria and Definitions for Excitation Systems for Synchronous Machines. Also included are auxiliary devices that are exposed to excitation system stresses. Examples of such auxiliary devices are temperature indicators, transducers, meters, etc. This standard does not cover the synchronous- machine field winding or field circuit breaker and discharge resistor. This standard supplements existing standards for components used on excitation systems: ANSI C19.3-1973, Industrial Control Apparatus - General; ANSI C19.4-1973, Industrial Control Apparatus - Enclosures; ANSI C19.5-1973, Industrial Control Apparatus - Switching or Controlling Devices; ANSI C19.6-1973, Industrial Control Apparatus - Control-Circuit Devices and Assemblies; ANSI C19.7-1973, Industrial Control Apparatus - Controllers and Controller Assemblies; ANSI C34.2-1968 (R1973), Practices and Requirements for Semiconductor Power Rectifiers; ANSI C37.18-1968 (R1975), Requirements for Field Discharge Circuit Breakers for Rotating Electric Machinery; ANSI/IEEE C57.12.00-197 3, General Requirements for Distribution, Power, and Regulating Transformers; ANSI/IEEE C57.12.90-1973, Test Code for Distribution, Power, and Regulating Transformers; and NEMA ICs1970 (R1975), Industrial Controls and Systems.