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This document provides a summary of the requirements of the various bodies
which currently define and regulate the no load power consumption and active mode efficiency of external power supplies. A summary of the performance levels of Power's products is included for reference.
Two important reasons for wanting to control the power taken by an external power supply are continuity of the energy supply and reduction of environmental impacts. Targets are given for external supplies because of the quantity sold each year, they normally do not have an off button and they are very commonly left plugged into the mains supply.
Many areas of the world are introducing limits for no load power consumption and operating efficiency of external power supplies. In the US there are three main parties, these being; California Energy Commission (CEC), US Congress with its Energy Independence and Security Act (EISA), both of which are mandatory and finally Energy Star which is voluntary. In Europe there is the Code of Conduct (CoC) for external power supply manufacturers which comes out of the Energy using Products (EuP) Directive. Other parts of the world that are enacting legislation are mainly basing their limits on previous Energy Star requirements.
Recently there has been a move by both CEC and European CoC to standardize their requirements with Energy Star to reduce the confusion of multiple limits. In the US, the CEC limits changed on 1st July 2008 and the Energy Star limits changed on 1st Nov 2008. In Europe, the CoC limits changed on 1st Jan, 2009.
The tables within Summary of Limits show the limits imposed by the four bodies. The average efficiency is taken as the mean of individual efficiencies at 25%, 50%, 75% and 100% loads.
A quick reference guide of the performance levels and compliance to the various standards for SR external power supplies is included in this document.
Energy Independence & Security Act 2007 (EISA)
In 2007 the US Congress passed a law effective 1st July, 2008, called the Energy Independence and Security Act of 2007 (EISA). This states that single output external power supplies of less than 250W manufactured on or after 1st July 2008 should meet maximum no load power consumption, and minimum active load efficiency limits with an input of 115VAC, 60Hz.
These requirements are identical to the 1st July, 2008 CEC limits meaning that any power supply meeting efficiency level IV will comply with the EISA requirements.
There are four exceptions included in the EISA legislation:
• If the power supply is to be used in an application requiring Federal Food and Drug Administration listing and approval as a medical device.
• If the power supply is charging either a detachable battery pack or the internal battery pack of a product which is primarily motor operated.
• If the power supply is to be used for spares for a product that was manufactured before 1st July, 2008.
• If the power supply is to be subsequently exported outside of the US.
Summary of Limits
Energy Star (Nov 1st, 2008 limits) EUP & CoC (1st Jan, 2009 limits)
No load power limits
Rated power No load consumption
0W to <50W 0.3W
≥50W to 250W 0.5W
Active mode power limits, O/P≥ 6 V
Rated power Average efficiency
0W to 1W ≥ 0.48 x rated power+0.14
>1W to ≤49W ≥[0.0626 x Ln(Rated power)]+0.622
>49W ≥ 0.87
In addition, Energy Star power supplies with an input power of 100 W and above must have minimum power factor of 0.9 at 115 VAC 60 Hz.
California Energy Commission (July 1st, 2008 limits) & EISA (2007 limits)
No load power limits
Rated power-- No load consumption
All --------------- 0.5W
Active mode power limits
Rated power ----- Average efficiency
0W to 1W --------- 0.5 x Rated power
>1W to 49W ------- ≥[0.09 x Ln(Rated power)] + 0.5
>49W ---------------- ≥0.85
Measurement Technique
The US Environmental Protection Agency (EPA) has devised a procedure for measuring the no load power consumption and active mode efficiency of external supplies. This procedure has been adopted as an acceptable test method to demonstrate compliance with
Energy Star, California Energy Commission, EISA and the EU Code of Conduct. The document can be found on the www.energystar.gov website and is titled “Test Method for Calculating the Energy Efficiency of Single-Voltage Ac-Dc and Ac-Ac Power Supplies” and is dated 11th August, 2004. This document sets out a standardized test method including test room conditions, accuracy of measuring instruments, quality of applied mains voltage and accuracy of load conditions. The document also details the information that is required for the test report.
Marking Requirements
To demonstrate compliance with the Energy Star and CEC requirements a mark must be placed on the product. The mark is made up of a Roman numeral and should now be a minimum of IV to show compliance with current requirements of CEC and EISA or a V to show compliance with Energy Star or CoC. |
