标准编号:	GB/T 12501-1990
中文名称:	电工电子设备防触电保护分类
英文名称:	Classification of electrical and electronic equipment with regard to protection against electric shock
行业分类:	GB    国家标准
发布日期:	1990-11-06
实施日期:	1991-7-1
标准状态:	abolished
作废日期:	2005-10-14
翻译语言:	英文
文件格式:	PDF
中文字符数:	2000 字
翻译价格(元):	280.0
交付时间:	付款后 1 个工作日

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. Classification of Electrical and Electronic Equipment with regard to Protection against Electric Shock This standard was developed by reference to the international standard IEC 536 (1976) Classification of Electrical and Electronic Equipment with regard to Protection against Electric Shock. 1 Subject Content and Application Scope This standard specifies the classification and definition of low-voltage electrical and electronic equipment intended for connection to an external power supply, with regard to protection against electric shock in the event of an insulation failure. This standard is applicable to electrical and electronic equipment with rated voltage not exceeding 660V AC r.m.s. If necessary, there is possibility of using it for higher voltages and other purposes in the related standard. This standard is applicable to electrical and electronic equipment for use by the general public in homes, offices, workshops, schools, farms and the like, and for medical and dental purposes. This standard is applicable to open-type equipment, that is to say equipment itself not provided with the protection against contact with live parts. 2 Normative References GB 2900.1 Electrotechnical Terminology - Fundamental Terms GB 3805 Safety Voltage GB 4208 Degrees of Protection Provided by Enclosure GB 4776 Electrical Safety Terminology 3 Terms 3.1 basic insulation insulation applied to live parts to provide basic protection against electric shock 3.2 supplementary insulation independent insulation applied in addition to basic insulation in order to provide protection against electric shock in the event of a failure of basic insulation 3.3 double insulation insulation comprising both basic insulation and supplementary insulation 3.4 reinforced insulation a single insulation system provides a degree of protection against electric shock equivalent to double insulation Note: the term "insulation system" does not imply that the insulation must be one homogeneous piece. It may comprise several layers which cannot be tested singly as supplementary or basic insulation. 3.5 safety impedance an impedance connected between live parts and accessible conductive parts, of such value that the current, in normal use and under likely fault conditions in the equipment, is limited to a safe value, and which is so constructed that the reliability is maintained throughout the life of the equipment 3.6 safety extra-low voltage (SELV) a voltage which does not exceed 50V AC r.m.s. between conductors, or between any conductor and earth, in a circuit which is isolated from the supply mains by means such as a safety isolating transformer or converter with separate windings Notes: ① Limitation to SELV in different industries is specified in the related professional standard. ② See GB 3805 for the limitation to voltages when direct contact with live part is involved. ③ The voltage limit shall not be exceeded either at full load or no-load, but it is assumed, for the purpose of this definition, that any transformer or converter is operated at its rated supply voltage. 4 Classes of Equipment The class numbers are not intended to reflect the safety level of the equipment, but only the means by which the safety is obtained. According to this classification, the protection against electric shock is provided by surrounding environment, equipment itself or power supply system. See Table A1 of Annex A. Equipment protection not against electric shock is specified in other national standard, e.g. degree of protection provided by enclosure is detailed in GB 4208. 4.1 Class 0 equipment Equipment in which protection against electric shock only relies upon basic insulation; this implies that there are no means for the connection of accessible conductive parts, if any, to the protective (earthing) conductor in the fixed wiring of the installation, reliance in the event of a failure of the basic insulation being placed upon the environment. 4.2 Class I equipment Equipment in which protection against electric shock does not rely on basic insulation only, but which includes an additional safety precaution in such a way that means are provided for the connection of accessible conductive parts to the protective (earthing) conductor in the fixed wiring of the installation. Notes: ① For equipment intended for use with a flexible cord or cable, this provision includes a protective (earthing) conductor as part of the flexible cord or cable. ② Where relevant standards permits, any component is at least subject to basic insulation and equipped with earthing terminal, but the power cord is not equipped with earthing conductor and the plug is not equipped with earthing pin, so it cannot be introduced to the power socket with earthing contact, provided that the protective conductor is not connected with the protective (earthing) conductor in fixed wiring, the protection is then equivalent to that of Class 0, but the earthing provisions of the equipment in all other respects shall fully comply with the requirements of Class I.

1 Subject Content and Application Scope 2 Normative References 3 Terms 4 Classes of Equipment Annex A (Informative Reference) Table for Principal Characteristics of Equipment and Precautions for Safety Additional Explanation

中华人民共和国国家标准 电工电子设备防触电保护分类 Classification of electrical and electronic equipment with regard to protection against electric shock GB/T 12501—90 本标准参照采用国际标准IEC 536(1976)《电工电子设备防触电保护的分类》。 1主题内容与适用范围 本标准规定了接至外电源的低压电工电子设备一旦基本绝缘失效按照防触电保护的方式所做的分类及定义。 本标准适用于额定电压不超过交流有效值660V的电工电子设备。需要时，有关专业标准也可用于电压更高的设备，或用于其他用途。 本标准适用于家庭、办公室、工厂，学校、农场及类似场所使用的以及医用的电工电子设备。 本标准不适用于开启式设备，即不适用于本身不具备防止触及其带电部分的设备。 2引用标准 GB 2900.1 电工名词术语 基本名词术语 GB 3805安全电压 GB 4208外壳防护等级的分类 GB 4776电气安全名词术语 3术语 3.1 基本绝缘basic insulation 带电部分上对防触电起基本保护作用的绝缘。 3.2 附加绝缘supplementary insulation 为了在基本绝缘损坏的情况下防止触电，而在基本绝缘之外使用的独立绝缘。 3.3 双重绝缘double insulation 同时具有基本绝缘和附加绝缘的绝缘。 3.4 加强绝缘reinforced insulation 相当于双重绝缘保护程度的单独绝缘结构。 注：“绝缘结构”这一术语并不意味着绝缘必须是同类件。它可以由几个不能象基本绝缘或附加绝缘那样单独试验的绝缘层组成。 3.5 安全阻抗safety impedance 连接于带电部分与易导电部分之间的阻抗，其值可在设备正常使用和可能发生故障的情况下把电流限制在安全值以内，并在设备的整个寿命期间保持其可靠性。 3.6安全特低电压safety extra-low voltage(SFLV) 用安全隔离变压器或具有独立绕组的变流器与供电干线隔离开的电路中，导体之间或任何一个导体与地之河有效值不超过50V的交流电压。 注：①不同行业对安全特低电压的限制由有关行业标准规定。 ②允许直接接触带电部分的限值见GB 3805。 ③不论满载或空载都不应超过电压限值。本定义假定任何变压器或变流器都是在额定供电电压下工作的。 4设备分类 分类的数字只表示设备防触电保护所采用的方式，并不反映设备的安全等级。 按照这一分类，防触电保护是由周围环境，设备本身或供电系统提供。见附录A(参考件)的表A1。 设备的非触电保护方式在其他国家标准中规定，如由外壳提供防护的等级见GB 4208。 4.1 0类设备 仅靠基本绝缘作为防触电保护的设备，当设备有能触及的可导电部分时，该部分不与设施固定布线中的保护(接地)线相连接，一旦基本绝缘失效，则安全性完全取决于使用环境。 4.2 1类设备 设备的防触电保护不仅靠基本绝缘，还包括一种附加的安全措施，即将能触及的可导电部分与设施固定布线中的保护(接地)线相连接。 注：①对于使用软电线或软电缆的设备，软电线或软电缆应具有一根保护(接地)芯线。 ②经有关标准允许.任何部件至步都是基本绝缘并装有接地端子，但电源软线不带接地导线，插头没有接地插脚，不能插入有接地插孔的电源插座的设备，只要其保护线没有和固定布线中的保护(接地)线相连接，就看作0类设备，但在所有其他方面，设备的接地措施应完全遵守I类设备的要求。 4.3 Ⅱ类设备 设备的防触电保护不仅靠基本绝缘还具备象双重绝缘或加强绝缘这样的附加安全措旋。这种设备不采用保护接地的措施，也不依赖于安装条件。 Ⅱ类设备可以具有保持保护接地回路连续性的器件，但其必须在设备内部，并按Ⅱ类的要求与能触及的可导电表面绝缘起来。 有金属外壳的Ⅱ类设备必要时可以采取将等电位连接线与外壳连接。 Ⅱ类设备可因工作(与保护目的不同)的原因，采取与大地连接的手段，但必须在技术上无损于安全水平。 注：①在特殊情况下，如某些Ⅱ类电子设备的信号端子，在主管技术部门认为需要安全阻抗，而且在技术上无损于安全水平时，Ⅱ类设备可以使用安全阻抗。 ②某些情况，需要把“全部绝缘外壳”的和“有金属外壳”的Ⅱ类设备加以区别。 4.4Ⅲ类设备 设备的防触电保护依靠安全特低电压(SELV)供电，且设备内可能出现的电压不会高于安全特低电压。 Ⅲ类设备不得具有保护接地手段。必要时，可因工作(与保护目的不同)的原因，采取与大地连接的手段，但必须在技术上无损于安全水平。 有金属外壳的Ⅲ类设备必要时可以采取将等电位连接线与外壳连接的手段。 附录A 设备主要特征及安全措施表 (参考件) A1表A1列出了设备按防触电保护分类的主要特征，指出了一旦基本绝缘失效所需要的安全措施。 表A1 类别 项目 0类 I类 Ⅱ类 Ⅲ类 设备主要特征 没有保护接地 有保护接地 有附加绝缘 不需要保护接地 设计成由安全 特低电压供电 安全措施 使用环境要与地绝缘 接地线与固定布线中的保护(接地)线连接 双重绝缘或加强绝缘 安全特低电压供电 附加说明： 本标准由中华人民共和国机械电子工业部提出。 本标准由机械电子部机械标准化所负责起草。 本标准主要起草人郭汀、张月亭、古其祥、李邦协。