Final answer:
Personnel may work on live electrical equipment only under stringent safety conditions and protocols, with measures like working 'one-handed' to prevent electrical current passing through the heart. Plastic insulation, grounding, and the proper use of circuit breakers and fuses are critical in preventing shock and thermal hazards.
Step-by-step explanation:
Personnel may work on live electrical equipment under certain conditions, such as during emergency repairs or when it is not feasible to de-energize equipment. However, working on live equipment should only be done after all other options have been exhausted, following proper safety protocols, and by experienced professionals.
When working with high-power electric circuits, one safety technique is to work 'one-handed' or 'keep one hand in your pocket.' This approach minimizes the risk of electrical current passing through the chest cavity, since current flowing through the heart can be fatal.
Electrical safety systems and devices are utilized to protect against shock and thermal hazards. Plastic insulation on wires is one such safety measure as it prevents contact with live/hot wires, reducing the risk of shocks and fires.
It's also why linemen touch the line with the back of the hand—to ensure voltage is zero without the risk of grasping and being unable to release due to muscle contraction caused by an electric shock.
For instance, the presence of moisture can drastically lower the resistance of the skin, which can result in more severe electric shocks.
This is relevant considering that blood and other bodily fluids also have low resistance, potentially heightening the risk for individuals on intravenous infusion (IV), as they may be more sensitive to microshocks.
Therefore, understanding the concepts of grounding, shock sensitivity, and the function of circuit breakers and fuses is crucial in preventing shock hazards. Lastly, circuit breakers and fuses protect by interrupting large currents that can cause fires or equipment damage, rather than small currents that can cause harmful shocks.