21 Working Voltage Measurements21.1 This test is to measure the working voltage of an electric energy storage system.21.2 The working voltage between live parts of opposite polarity, live and dead metal parts, live parts and a metal enclosure, and live and ground connections under both normal charging and discharging conditions as specified by the manufacture is measured.21.3 The dead metal parts and metal enclosure shall be assumed to be connected to the negative terminal of the system for testing purpose.21.4 The values obtained during the measurements outlined in 21.2 shall be used to verify electrical spacings criteria per 5.5