This recommended practice identifies specifications that should be provided to characterize instrumentation used to measure the steady state Root mean square (rms) values of magnetic and electric fields with sinusoidal frequency content in the range 10 Hz to 3 kHz in residential and occupational settings as well as in transportation systems. The dynamic ranges of interest are 0.01 MicroT (0.1 mG) to 10 mT (100 G) and 1 V/m to 30 kV/m for magnetic and electric fields, respectively. In addition, this recommended practice -- Defines terminology. --Describes general characteristics of fields. --Surveys operational principles of instrumentation. -- Indicates methods of calibration. -- Identifies significant sources of error. While field meter specifications are identified, frequencies and field levels that should be used for calibration purposes, and limits on measurement uncertainty are not recommended in this standard. Rather, it is left to standards that describe measurement protocols for different environments to indicate specific calibration points and uncertainty requirements. However, sources of uncertainty during calibration and measurements are identified and guidance is provided on how they should be combined to determine total measurement uncertainty.