and which one to use in my country Egypt ?
NFPA - National Fire Protection Association - National code that covers anything to do with flamable stuff (electrical, dust, combustibles, sprinklers, fire alarms, etc) (United States) NEC - National Electric Code a.k.a NFPA 70 (NEC is a section of the NFPA code) - Addresses proper installation of electrical equipment, devices and wiring(United States) NEMA - National Electric Manufacturers Association- trade organization for electrical manufacturers. Sets common rules, practices and certification for the manufacture of electrical components and devices (United States) IEC - International Electric Code - International version of NEMA IEC would most likely cover devices made for use in Egypt. I'm not sure what organization or governing body would address the installation there.
