標準編號:	GB/T 12501-1990
中文名稱:	電工電子設備防觸電保護分類
英文名稱:	Classification of electrical and electronic equipment with regard to protection against electric shock
行業分類:	GB    國家標準
發布日期:	1990-11-06
實施日期:	1991-7-1
標準狀態:	abolished
作廢日期:	2005-10-14
翻譯語言:	英文
文件格式:	PDF
中文字符數:	2000 字
翻譯價格(元):	280.0
交付時間:	付款后 1 個工作日

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

中華人民共和國國家標準 電工電子設備防觸電保護分類 Classification of electrical and electronic equipment with regard to protection against electric shock GB/T 12501—90 本標準參照采用國際標準IEC 536(1976)《電工電子設備防觸電保護的分類》。 1主題內容與適用范圍 本標準規定了接至外電源的低壓電工電子設備一旦基本絕緣失效按照防觸電保護的方式所做的分類及定義。 本標準適用于額定電壓不超過交流有效值660V的電工電子設備。需要時，有關專業標準也可用于電壓更高的設備，或用于其他用途。 本標準適用于家庭、辦公室、工廠，學校、農場及類似場所使用的以及醫用的電工電子設備。 本標準不適用于開啟式設備，即不適用于本身不具備防止觸及其帶電部分的設備。 2引用標準 GB 2900.1 電工名詞術語 基本名詞術語 GB 3805安全電壓 GB 4208外殼防護等級的分類 GB 4776電氣安全名詞術語 3術語 3.1 基本絕緣basic insulation 帶電部分上對防觸電起基本保護作用的絕緣。 3.2 附加絕緣supplementary insulation 為了在基本絕緣損壞的情況下防止觸電，而在基本絕緣之外使用的獨立絕緣。 3.3 雙重絕緣double insulation 同時具有基本絕緣和附加絕緣的絕緣。 3.4 加強絕緣reinforced insulation 相當于雙重絕緣保護程度的單獨絕緣結構。 注：“絕緣結構”這一術語并不意味著絕緣必須是同類件。它可以由幾個不能象基本絕緣或附加絕緣那樣單獨試驗的絕緣層組成。 3.5 安全阻抗safety impedance 連接于帶電部分與易導電部分之間的阻抗，其值可在設備正常使用和可能發生故障的情況下把電流限制在安全值以內，并在設備的整個壽命期間保持其可靠性。 3.6安全特低電壓safety extra-low voltage(SFLV) 用安全隔離變壓器或具有獨立繞組的變流器與供電干線隔離開的電路中，導體之間或任何一個導體與地之河有效值不超過50V的交流電壓。 注：①不同行業對安全特低電壓的限制由有關行業標準規定。 ②允許直接接觸帶電部分的限值見GB 3805。 ③不論滿載或空載都不應超過電壓限值。本定義假定任何變壓器或變流器都是在額定供電電壓下工作的。 4設備分類 分類的數字只表示設備防觸電保護所采用的方式，并不反映設備的安全等級。 按照這一分類，防觸電保護是由周圍環境，設備本身或供電系統提供。見附錄A(參考件)的表A1。 設備的非觸電保護方式在其他國家標準中規定，如由外殼提供防護的等級見GB 4208。 4.1 0類設備 僅靠基本絕緣作為防觸電保護的設備，當設備有能觸及的可導電部分時，該部分不與設施固定布線中的保護(接地)線相連接，一旦基本絕緣失效，則安全性完全取決于使用環境。 4.2 1類設備 設備的防觸電保護不僅靠基本絕緣，還包括一種附加的安全措施，即將能觸及的可導電部分與設施固定布線中的保護(接地)線相連接。 注：①對于使用軟電線或軟電纜的設備，軟電線或軟電纜應具有一根保護(接地)芯線。 ②經有關標準允許.任何部件至步都是基本絕緣并裝有接地端子，但電源軟線不帶接地導線，插頭沒有接地插腳，不能插入有接地插孔的電源插座的設備，只要其保護線沒有和固定布線中的保護(接地)線相連接，就看作0類設備，但在所有其他方面，設備的接地措施應完全遵守I類設備的要求。 4.3 Ⅱ類設備 設備的防觸電保護不僅靠基本絕緣還具備象雙重絕緣或加強絕緣這樣的附加安全措旋。這種設備不采用保護接地的措施，也不依賴于安裝條件。 Ⅱ類設備可以具有保持保護接地回路連續性的器件，但其必須在設備內部，并按Ⅱ類的要求與能觸及的可導電表面絕緣起來。 有金屬外殼的Ⅱ類設備必要時可以采取將等電位連接線與外殼連接。 Ⅱ類設備可因工作(與保護目的不同)的原因，采取與大地連接的手段，但必須在技術上無損于安全水平。 注：①在特殊情況下，如某些Ⅱ類電子設備的信號端子，在主管技術部門認為需要安全阻抗，而且在技術上無損于安全水平時，Ⅱ類設備可以使用安全阻抗。 ②某些情況，需要把“全部絕緣外殼”的和“有金屬外殼”的Ⅱ類設備加以區別。 4.4Ⅲ類設備 設備的防觸電保護依靠安全特低電壓(SELV)供電，且設備內可能出現的電壓不會高于安全特低電壓。 Ⅲ類設備不得具有保護接地手段。必要時，可因工作(與保護目的不同)的原因，采取與大地連接的手段，但必須在技術上無損于安全水平。 有金屬外殼的Ⅲ類設備必要時可以采取將等電位連接線與外殼連接的手段。 附錄A 設備主要特征及安全措施表 (參考件) A1表A1列出了設備按防觸電保護分類的主要特征，指出了一旦基本絕緣失效所需要的安全措施。 表A1 類別 項目 0類 I類 Ⅱ類 Ⅲ類 設備主要特征 沒有保護接地 有保護接地 有附加絕緣 不需要保護接地 設計成由安全 特低電壓供電 安全措施 使用環境要與地絕緣 接地線與固定布線中的保護(接地)線連接 雙重絕緣或加強絕緣 安全特低電壓供電 附加說明： 本標準由中華人民共和國機械電子工業部提出。 本標準由機械電子部機械標準化所負責起草。 本標準主要起草人郭汀、張月亭、古其祥、李邦協。