Ground Wire Resistance

The ground wire resistance is a crucial part of the measurement.First,it is assumed that all electrical receptacles in the patient room are tied together to a known good earth ground.The receptacles are tested after installation and generally at regular intervals thereafter.Since a good earth ground is available in the room,all line connected devices must be referenced (connected) to this same ground to help avoid shock hazard.This connection is achieved via the ground conductor in the power cord of each device.The generally accepted maximun value for ground wire resistance is 0.5 ohms.