IEC 60359:1987

Applies to the specification of the performance of electrical and electronic equipment and instruments and the accessories used with them which measure electrical quantities (indicating and recording instruments), or supply measured electrical quantities (supply instruments), such as signal generators and some power supplies, or measure non-electrical quantities using electrical means, excluding any parts, such as transducers.
The expression of performance covers only the electrical or electronic part. This standard provides methods for ensuring uniformity in the specification and measurement of errors of the above equipment.