ballast efficiency
(A)The term “ballast efficiency” means, in the case of a high intensity discharge fixture, the efficiency of a lamp and ballast combination, expressed as a percentage, and calculated in accordance with the following formula: Efficiency = P/P. (B)For the purpose of subparagraph (A)— (i)Pshall equal the measured operating lamp wattage; (ii)Pshall equal the measured operating input wattage; (iii)the lamp, and the capacitor when the capacitor is provided, shall constitute a nominal system in accordance with the ANSI Standard C78.43–2004; (iv)for ballasts with a frequency of 60 Hz, Pand Pshall be measured after lamps have been stabilized according to section 4.4 of ANSI Standard C82.6–2005 using a wattmeter with accuracy specified in section 4.5 of ANSI Standard C82.6–2005; and (v)for ballasts with a frequency greater than 60 Hz, Pand Pshall have a basic accuracy of +/- 0.5 percent at the higher of— (I)3 times the output operating frequency of the ballast; or (II)2 kHz for ballast with a frequency greater than 60 Hz. (C)The Secretary may, by rule, modify the definition of “ballast efficiency” if the Secretary determines that the modification is necessary or appropriate to carry out the purposes of this chapter.