Uniform procedures for the measurement of the power frequency electric field and dc electric field when ac/dc power transmission lines are installed in parallel or on shared towers are established in this recommended practice. The measurement ranges and layout of measurement points, data recording and processing, and result evaluation methods of parallel power transmission lines of different voltage levels are recommended.

This document provides recommendations for electromagnetic field measurement locations, procedures, and results evaluation for corridors containing both alternating current (ac) and direct current (dc) overhead transmission lines. This document primarily addresses application of parallel ac and dc lines that are in close proximity either on separate or shared structures.

The purpose of this recommended practice is to provide guidance beyond what is available in IEEE Std 644 (measuring ac fields), IEEE Std 1308 (ac measurement equipment), and IEEE Std 1227 (dc measurement equipment) that are applicable to shared ac/dc corridors.