External power supplies are power adaptors used to convert household electric current into lower voltage DC current - in order to operate a large variety of household and office products like electric tooth brushes and shavers, mobile and cordless phones, laptops and tablets, as well as printers, routers and modems.

It is widely recognized that the losses caused by inefficiencies in external power supplies (EPS), such as adapters, are a major contributor to energy use globally, with a corresponding negative environmental impact. The California Energy Commission responded back in 2004, with mandatory standards for efficiency and no-load power draw, followed by the European Union. Over the years, the US standards went in and out of step with updates, but today there is substantial agreement between the current US Department of Energy (DOE) Level VI. The regulation on ecodesign covers external power supplies with an output power of maximum 250 W, which are intended to work with electrical and electronic household and office equipment. From April 2020, Regulation (EC) No 278/2009 will be replaced by Regulation (EU) 2019/1782.

Outside of the US and EU, countries with significant EPS markets have adopted voluntary and sometimes mandatory programs, generally harmonized with the US and EU standards. Other countries such as China and Japan have published their own requirements.

Canada, for example, has kept up with the US and DOE Level VI performance requirements through the National Resources Canada agency. These measures have been mandatory since 2017, although some provinces such as Ontario and Quebec have their own additional requirements.

Australia and New Zealand, with their standard AS-NZS 4665.2-2005, made compliance with DOE Level (Energy Star Version) mandatory in 2008 as a minimum, and Level IV voluntary for high-efficiency products. In 2012, the Greenhouse and Energy Minimum Performance Standards (GEMS) Act came into force, consolidating state and territory laws, mandating Minimum Energy Performance Standards (MEPS) for a range of products. The AS-NZS standard is referenced with efficiency and no-load values largely equivalent to the DOE various levels. The minimum performance required is still Level IV. Israel has similar arrangements with its standard.

Korea, Another large market, has mandatory requirements for compliance with DOE for energy efficiency. The Korean E-Standby program to reduce standby losses to less than 1 W in EPS products was voluntary in 2007 and mandatory to be less than 0.5 W from 2010, after a transition period. Labeling is an important part of the Korean programs to improve efficiency, with the country "naming and shaming" with a mandatory warning label on products that failed to meet the voluntary limits.

Other countries have their own standards that largely follow the DOE or EU requirements, such as in Mexico, where NOM-029 ENER-2017 applies for separately sold ac-dc EPS products up to 250 W.

Large markets such as Russia and India have no evident programs directly related to external power supplies. However, the Bureau of Energy Efficiency in India collaborates with major economies such as the US, China, and Russia on energy-related policies at a high level. India is also a participant in the Paris-based International Partnership for Energy Efficiency Cooperation (IPEEC) which promotes global energy-saving initiatives such as SEAD, the Super-Efficient Equipment and Appliance Deployment initiative. SEAD has schemes such as the Global Efficiency Medal, similar to the Japan Top Runner, which identifies and rewards best-performing products in various categories, but again, not specifically EPS.

A new single market that comes into existence on January 1, 2021, is the UK after Brexit - its split with the EU. The UK government has confirmed its commitment to maintain the standards set by the EU Ecodesign Directive with equivalent UK legislation and perhaps even tighten the regulations in the future. For more information on this new standard, see KSPOWER blog about the UKCA Mark.