What is the safety voltage? The single-phase voltage for low voltage distribution network in China are based on ac 50 hz, 220 v, so, in addition to the need to use safe voltage power supply parts of lamps and lanterns, average commonly used lamps and lanterns of voltage is 220 v. communication safety voltage is used to prevent electric shock accident specific power supply voltage of the series, the series voltage upper limit under normal and fault conditions, any voltage between any two conductors or conductors and ground are no more than ac (50 hz) RMS 50 v. Safety voltage class is divided into 50 v, 42 v, 36 v, 24 v, 12 v, 6 v, usually should be selected according to use environment, use factors such as different safety voltage. For example, if in the cable tunnel, lighting lamps and lanterns can choose 36 v safety voltage power supply; The safety of the underwater lights should choose no more than 12 v voltage of power supply. This particular power supply is to point to by special safety voltage power supply, the power supply input circuit and output circuit must be carried out on the isolation circuit, and work under safe voltage circuit, must have nothing to do with any other electrical system and electrically conductive parts for electrical isolation.

32. The abbreviation of CIE which institution? International Commission on illumination (appointed the Internationale DE I Eclairage) is the international academic organization in the field of lighting engineering, abbreviated CIE, stems from a French word initials. CIE is by the international lighting engineering research on color and visual, light manufacturing, lighting design, optical measurement, optical biological and photochemical division of multidisciplinary academic organization, founded in 1913, headquartered in Vienna, Austria. International commission on illumination to member countries involved in international cooperation and exchanges in the field of lighting, so far there are 38 members groups from different countries and regions, China lighting association, the Hong Kong institute of lighting are members of the international commission on illumination. International lighting council member countries and regions including: Argentina, Austria, Australia, Belgium, Brazil, Bulgaria, Canada, China, Croatia, the Czech republic, Denmark, France, Germany, Britain, Hungary, Iceland, India, Israel, Italy, Japan, the Netherlands, New Zealand, Norway, Pakistan, Poland, Romania, Russia, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, the United States and China's Hong Kong region. Is the main task of the international commission on illumination: a. for lighting engineering academic research provides an international BBS. B. light and lighting in the field of basic norms and metrological specification. C. for light and lighting in the field of international standards and provide the guidance of the principle in the promotion of national standard. D. edited and light energy in the field of the relevant standards, reports, and other publications. E. involved with other international organizations in the field of light and lighting to keep in touch and academic exchanges.