Ecg Lead Leakage

Many ESAs incorporate ECG lead connections,so that the ECG leads of monitor and other such devices may be tested for leakage.Just asthere are specifications for chasis orcase leakage current,Ecg leads also have maximum leakage current values assigned.

Most lead equip ESAs will have either 5 or 10 lead connections.To the uninitiated,this can be confusing and intimidating array of connections.Risk current may be available on the DUT from one of the insulated leads to ground,or from the one to another.Either situation poses a shock hazard.Therefore,most ESAs are set up to check either "lead to ground" or "lead to lead".

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.

Leakage current - The Main Ingredient of Safety Testing

The primary component - the bottom line,if you will..is the amount of microshock current that would flow through a patient who comes in contact with the DUT (Device Under Test).The ESA simulates the patient and indicates the amountof leakage current the patient would receive if someone was exposed to the DUT.