Energy efficiency for external power supplies (EPS)
Controlling the power consumed by external power supplies, whether when they are supplying power or when disconnected from the load, is important for continuity of the energy supply and reduction of environmental impacts. Legislation and targets are set for external power supplies because of proliferation, lack of on/off control and because they are commonly left connected to the mains supply when not in use.
Many areas around the world have introduced legislation for no load power consumption and active mode efficiency for external power supplies. In the USA there are a number of bodies legislating on energy efficiency; the California Energy Commission (CEC), US Congress with its Energy Independence and Security Act (EISA) and recently the United States Department of Energy (DoE). There is also Energy Star which sets limits for electrical and electronic equipment. In Europe there is the Energy related Products (ErP) Directive formerly known as the Energy Using Products (EuP) directive, which is mandatory. There is also the EU Code of Conduct for external power supplies which is voluntary. In Canada there is Natural Resources Canada (NRCan) and in Australia the Minimum Energy Performance Standard (MEPS).