While it’s true that many countries outside of the continental U.S. use North American plugs, and many countries beyond the continent of Europe use European plugs, the majority of countries have their own proprietary plug patterns that adhere to their own standards as well as its safety agency or agencies of choice. Complicated? Yes, and no.
A country’s standards usually includes mains power terminology—voltage, amperage, frequency, plug, and other designs. Safety agency standards typically set safety standards for electrical components such as the types of plastic used in plugs and sockets, and the plastic composition’s rate of flame retardancy or overheating values in components such as plugs and sockets, and conductor wire insulations and cord jacket dimensions and material characteristics. A great example of agency standards is found by grazing UL’s iQ site. Standards are typically published by regional or global safety agencies such as UL and VDE, and are vital to manufacturers of power cords and power cord components to obtain country-specific product approvals and certifications—what resins for your product have been approved through safety agency testing? This is a great time-saver for manufacturers as they can allocate resources ensuring products meet exact specifications and dimensions—within published minimal tolerances—for components, including plugs, sockets, blade and pin lengths, the crimp height of conductor wire, etcetera.
While plugs and sockets adhere to national and regional standards, the majority of plugs and sockets also meet international standards since many manufacturers export their products abroad. To do so, of course, they will have to comply with, say, the IEC 60320 standard concerning power cord sets. While nearly every other safety agency publishes power cord set standards and testing methodologies and results, the IEC publishes standards including testing methodologies but does not actually test products in labs like UL, VDE, JET, and other safety agencies do.
Plugs can be rated as Class I (grounded) or Class II (ungrounded), which are two of the most prevalent categories. Class III is very low-power appliances designed to operate at safety extra-Low voltage (SELV), typically not exceeding 50V AC or 120V DC, and is used in electric shavers, toys, and other small devices. Also, plugs can be molded or rewireable. Molded plugs cannot be modified once they are removed from a molding die, whereas a rewireable plug can be disassembled by removing its screws for inspection or repair, then rewired back onto new or existing cable.
As noted earlier, a must-have for exporting power cords, especially when trying to save your country-specific cord sets for a limited number of wall sockets in inconvenient locations, the IEC 60320 line of accessory power components contain inlets, outlets, plug connectors, connectors and jumper cords to make exportation simple while conserving your country-specific plugs. By using a single country-specific power cord and a 4-12 outlet accessory power strip (APS), users across nearly every industry can power up to 12 machines or devices using only one country-specific power cord.
In a civilization where business and leisure approach the speed of electricity or even light, power cord customers certainly expect to unbox their cord sets and immediately plug them into the wall socket without further hardware configuration. It will often look something like this: plugging your country-specific plug into the wall socket (mains power) and plugging the opposite end of that cord— terminated with an IEC 60320 C13 connector—into a C14 inlet in the accessory power strip, the latter also containing 4-12 Sheet F outlets. Now, IEC 60320 jumper cords bearing IEC 60320 Sheet E plug connectors can be plugged into the APS’ row of Sheet F outlets. Finally, the opposite end of the Sheet E jumper cords are terminated with C13s to plug directly into equipment via their built-in C14 inlets.
Interpower offers its Guide to Worldwide Plug and Socket Patterns and Power Mains (Single-Phase) (Worldwide Plug Patterns) under their website’s “Guides, Charts, and Brochures” to help customers choose the correct plug pattern. The guide provides a replete list of country-specific plug patterns and their paired sockets to specify compatibility worldwide. Product specifications can be found on the website for each of the plugs and sockets available through Interpower, including their drawings and dimensions, amperages and voltages, proper wiring information, flammability ratings, and maximum current ratings. And more. All Interpower products have agency approvals and certifications. Interpower also provides the knowledge for cord set safety requirements that affect not only the choice of plugs and sockets, but entire electrical designs. And yet, this is a mere fraction of the power cord and component content found on Interpower’s website.