NEMA and IEC are the two most common standards for power cords used in North America. NEMA connectors are on the side of the power cord that plugs into an AC wall outlet. IEC connectors are the side that plugs into devices like computers or TVs. By and large, NEMA and IEC are compatible with each other. There are many similarities between NEMA and IEC standards, but they are not quite the same.

NEMA Connectors

NEMA is an acronym for the National Electrical Manufacturers Association. Established in 1926, NEMA is an American organization focused on creating, establishing, and promoting safety standards for electrical equipment. Power cords are one of many items that fall under their jurisdiction. Despite being an American organization, NEMA standards are also primarily used in Canada and Mexico as well as parts of Central and South America, nearby small island nations such as Cuba, and some larger countries across the sea like Japan.

NEMA connectors are labeled as two numbers separated by a dash. The first number indicates the voltage rating of the cable; “5” stands for 125 volts and “6” stands for 250 volts. The second number indicates the amperage of the plug. There will also be a letter after the numbers, either a “P” for plug or an “R” for receptacle. For example, a 5-15P connector will be a plug rated for 125 volts and 15 amps.

NEMA 5-15P (right) vs. 6-15P (left)

Another standard under NEMA is hospital-grade power cords. The US and Canada have strict standards for power cords used in medical environments. These standards must be followed by law in both countries. Hospital-grade cords have higher safety standards than conventional power cords and are made with enhanced durability.

IEC Connectors

IEC stands for International Electrotechnical Commission. It is a non-profit, non-government organization founded in 1906 that sets international standards on electric and electronic devices. Power cords are one of many devices that fall under their umbrella, specifically IEC 60320. This covers cords that are numbered from C1 to C24, although only a few of these connectors are commonly used throughout the world.

The most common IEC connectors are C13, C15, and C19. C13 is used on household and office electronics such as computers and televisions. C15 is used for devices that generate large amounts of heat, such as electric kettles or small computer networking closets. C19 is used for equipment with higher amperage that requires a constant supply of power, such as data servers or similar rack-mounted hardware.

From left to right: IEC C13, C15, and C19

Power cords are generally not evaluated as a single item. The connectors and wiring are approved separately. A small number of countries, such as China and Argentina, do approve the whole cord at once but that is the exception, not the rule. Having international standards like IEC connectors makes these evaluations easier from one country to the next.

Because IEC cords are used in different countries with different standards, they do not have universal amperage ratings. For instance, a C13 plug can handle up to 15 amps, which is perfectly fine according to UL (American) standards. But in Europe, the same plug is only approved for up to 10 amps by European regulatory committees. Be sure to check the specs on a cable before buying to make sure it matches the technical requirements of your equipment and legal requirements of your country.