What are the major methods to prevent macroshock and microsh

What are the major methods to prevent macroshock and microshock?

Solution

Macroshock

  Macroshock has the potential for both burns and cardiac arrhythmias. Currents pass through the extremities mostly through the muscles. A current flowing from arm to arm, or arm to leg, must pass through the thorax. In the thorax the current is split between the chest wall and the great vessels, which obviously deliver the current directly to the myocardium.

There are several steps to prevent macroshock in the Equipment must be designed so the hot wire cannot easily short out with the chassis. Every chassis must be grounded. The ground wires must be regularly inspected, because a failed ground wire will permit the chassis to come up to full line voltage unnoticed. Finally, patients should not be connected to potential grounds, or to monitoring equipment which provides a direct connection to ground
One of the best ways of preventing macroshocks, however, is the line isolation transformer. The isolation transformer is really a very simple device which prevents a circuit from being completed by connection to ground    Microshock:
  Microshock refers to currents delivered directly to the myocardium via intracardiac electrodes or catheters. Because the current is delivered to a very small area, only a very small current is required to reach the fibrillation threshold. The currently accepted minimum current is 10 mA

How much safety does the isolation transformer provide against microshock hazard? First, if the ground wire is intact then it should not be possible for the chassis to become connected to either lead without setting off the line isolation monitor. However, there is always a partial connection between the power wires and the chassis simply because insulation can never be 100%. How high can this voltage rise before the line isolation monitor signals a fault?The line isolation monitor will signal a warning if the resistance between the ground and either wire is less than 75,000 ohms, which corresponds to a 2mA current running through the ground wire (150V / 75,000 ohms).