Human current sensitivities and resistance values in the presence of electrically energized objects

Modeling the response of the human body to electrical stimuli is a complex task. In the simplest model, two types of impedances are used: (1) skin and (2) internal. The skin is a layered structure, with both resistance and capacitance. The resistance is nonlinear in voltage and time. The impedance of the interior may be considered as resistive, comparable to a similar volume of saline at human body concentration. The skin capacitance causes impedance to decrease with frequency, as AC current shunts the high skin resistance. Data on human and animal body electrical resistance under various conditions is widely available in the literature, and consists of both original research and numerous compilations of data for various applications. Curve fitting was used to obtain expressions for human body impedance and shock sensitivity from published data. The IEC479 standards are compared with the "electrocution equation". Electrical safety is important in industrial work. Here, an electrician may come into contact with energized equipment, particularly at low voltages. Electrical shock in the home is normally from 120 Volt systems, particularly appliances and swimming pools. Calculations of shocking current in cases of inadvertent contact with a 120 Volt source are used to estimate the hazards