电流对人类和家畜的影响.第1部分:一般特性

[中文适用范围]： 就通过人体的一条给定的电流通路而言，对人的危险主要取决于电流的数值和通电时间。但是在 许多情况下，以下各条款规定的时间／电流区域，实际上并不直接用于电击防护设计。必须以时间为函 数的接触电压(即通过人体的电流与人体阻抗的乘积)的允许极限值作为判据。由于人体的阻抗随接触 电压而变化。所以电流与电压的关系不是线性的，因此需要给出其关系数据。人体的不同部分如皮肤、 血液、肌肉、其他的组织和关节对电流呈现的阻性和容性分量组成了人体阻抗。 人体阻抗的数值取决于若干因素，特别是电流路径，接触电压、电流的持续时间、频率、皮肤潮湿程 度、接触表面积、施加的压力和温度。 本标准中所列阻抗值主要是对尸体和少数活人身上进行测定所得的数据仔细审核而得的。 交流电流对人体的效应，基本上以电气装置中最常用的频率为50 Hz或60 Hz的交流电流效应的 有关研究结果为依据，但所给出的数据被认为可适用于15 Hz至100 Hz的频率范围，在此范围起始端 频率的阈值比50 Hz或60 Hz的阈值为高，主要是，本章首要考虑心室纤维性颤动的危险，因为它是致 命事故的主要机制。 从直流应用的数量来看，直流发生的事故比预期的要少得多，只有在其非常不利的情况下，例如在 矿井中才会发生致命事故；部分原因是被抓住的直流带电体较易于摆脱，以及当电击持续时间大于心博 周期时，直流电流的心室颤动阈比交流的要高得多。 注：GB／T 13870包括关于各种生理效应的人体阻抗和人体电流阈值的资料。这种资料可以被组合，以便引用于某 种人体电流通路、接触的潮湿条件以及皮肤接触面积的交流和直流的接触电压阈的评估，有关接触电压阈的生 理效应的资料包括在GB/T 3805标准中。 [外文原描述]： IEC 60479-1:2005 For a given current path through the human body, the danger to persons depends mainly on the magnitude and duration of the current flow. However, the time/current zones specified in this publication are, in many cases, not directly applicable in practice for designing measures of protection against electrical shock. The necessary criterion is the admissible limit of touch voltage (i.e. the product of the current through the body called touch current and the body impedance) as a function of time. The relationship between current and voltage is not linear because the impedance of the human body varies with the touch voltage, and data on this relationship is therefore required. The different parts of the humanbody (such as the skin, blood, muscles, other tissues and joints) present to the electric current a certain impedance composed of resistive and capacitive components. The values of body impedance depend on a number of factors and, in particular, on current path, on touch voltage, duration of current flow, frequency, degree of moisture of the skin, surface area of contact, pressure exerted and temperature. The impedance values indicated in this technical specification result from a close examination of the experimental results available from measurements carried out principally on corpses and on some living persons. It has the status of a horizontal standard in accordance with IEC Guide 104 . The contents of the corrigenda of October 2006 and June 2013 have been included in this copy.