#### § 431.326 Energy conservation standards and their effective dates.

(a) Except as provided in [paragraph (b)](/on/2024-09-17/title-10/section-431.326#p-431.326(b)) of this section, each metal halide lamp fixture manufactured on or after January 1, 2009, and designed to be operated with lamps rated greater than or equal to 150 watts but less than or equal to 500 watts shall contain—

(1) A pulse-start metal halide ballast with a minimum ballast efficiency of 88 percent;

(2) A magnetic probe-start ballast with a minimum ballast efficiency of 94 percent; or

(3) A nonpulse-start electronic ballast with either a minimum ballast efficiency of 92 percent for wattages greater than 250 watts; or a minimum ballast efficiency of 90 percent for wattages less than or equal to 250 watts.

(b) The standards described in [paragraph (a)](/on/2024-09-17/title-10/section-431.326#p-431.326(a)) of this section do not apply to—

(1) Metal halide lamp fixtures with regulated lag ballasts;

(2) Metal halide lamp fixtures that use electronic ballasts that operate at 480 volts; or

(3) Metal halide lamp fixtures that;

(i) Are rated only for 150 watt lamps;

(ii) Are rated for use in wet locations; as specified by the National Fire Protection Association in NFPA 70 (incorporated by reference; *see* [§ 431.323](/on/2024-09-17/title-10/section-431.323)); and

(iii) Contain a ballast that is rated to operate at ambient air temperatures above 50 °C, as specified in UL 1029, (incorporated by reference; *see* [§ 431.323](/on/2024-09-17/title-10/section-431.323)).

(c) Except when the requirements of [paragraph (a)](/on/2024-09-17/title-10/section-431.326#p-431.326(a)) of this section are more stringent (*i.e.,* require a larger minimum efficiency value) or as provided by [paragraph (e)](/on/2024-09-17/title-10/section-431.326#p-431.326(e)) of this section, each metal halide lamp fixture manufactured on or after February 10, 2017, must contain a metal halide ballast with an efficiency not less than the value determined from the appropriate equation in the following table:

| Designed to be operated with lamps of the following rated lamp wattage | Tested input voltage‡‡ | Minimum standard equation‡‡ % |
| --- | --- | --- |
| ≥50 W and ≤100 W | Tested at 480 V | (1/(1 + 1.24 × P^(−0.351))) − 0.020†† |
| ≥50 W and ≤100 W | All others | 1/(1 + 1.24 × P^(−0.351)) |
| >100 W and <150† W | Tested at 480 V | (1/(1 + 1.24 × P^(−0.351))) − 0.020 |
| >100 W and <150† W | All others | 1/(1 + 1.24 × P^(−0.351)) |
| ≥150 ‡ W and ≤250 W | Tested at 480 V | 0.880 |
| ≥150 ‡ W and ≤250 W | All others | For ≥150 W and ≤200 W: 0.880 |
| | | For >200 W and ≤250 W: 1/(1 + 0.876 × P^(−0.351)) |
| >250 W and ≤500 W | Tested at 480 V | For >250 and <265 W: 0.880 |
| | | For ≥265 W and ≤500 W: (1/(1 + 0.876 × P^(−0.351)) − 0.010 |
| >250 W and ≤500 W | All others | 1/(1 + 0.876 × P^(−0.351)) |
| >500 W and ≤1000 W | Tested at 480 V | For >500 W and ≤750 W: 0.900 |
| | | For >750 W and ≤1000 W: 0.000104 × P + 0.822 |
| | | For >500 W and ≤1000 W: may not utilize a probe-start ballast |
| >500 W and ≤1000 W | All others | For >500 W and ≤750 W: 0.910 |
| | | For >750 W and ≤1000 W: 0.000104 × P + 0.832 |
| | | For >500 W and ≤1000 W: may not utilize a probe-start ballast |
| | | |
| --- | --- | --- |
| † Includes 150 W fixtures specified in [paragraph (b)(3)](/on/2024-09-17/title-10/section-431.326#p-431.326(b)(3)) of this section, that are fixtures rated only for 150 W lamps; rated for use in wet locations, as specified by the NFPA 70 (incorporated by reference, see [§ 431.323](/on/2024-09-17/title-10/section-431.323)), [section 410.4(A)](/on/2024-09-17/title-10/section-410.4#p-410.4(A)); and containing a ballast that is rated to operate at ambient air temperatures above 50 °C, as specified by UL 1029 (incorporated by reference, see [§ 431.323](/on/2024-09-17/title-10/section-431.323)). | | |
| ‡ Excludes 150 W fixtures specified in [paragraph (b)(3)](/on/2024-09-17/title-10/section-431.326#p-431.326(b)(3)) of this section, that are fixtures rated only for 150 W lamps; rated for use in wet locations, as specified by the NFPA 70, [section 410.4(A)](/on/2024-09-17/title-10/section-410.4#p-410.4(A)); and containing a ballast that is rated to operate at ambient air temperatures above 50 °C, as specified by UL 1029. | | |
| †† P is defined as the rated wattage of the lamp the fixture is designed to operate. | | |
| ‡‡ Tested input voltage is specified in [10 CFR 431.324](/on/2024-09-17/title-10/section-431.324). | | |

(d) Except as provided in [paragraph (e)](/on/2024-09-17/title-10/section-431.326#p-431.326(e)) of this section, metal halide lamp fixtures manufactured on or after February 10, 2017, that operate lamps with rated wattage >500 W to ≤1000 W must not contain a probe-start metal halide ballast.

(e) The standards described in [paragraphs (c)](/on/2024-09-17/title-10/section-431.326#p-431.326(c)) and [(d)](/on/2024-09-17/title-10/section-431.326#p-431.326(d)) of this section do not apply to—

(1) Metal halide lamp fixtures with regulated-lag ballasts;

(2) Metal halide lamp fixtures that use electronic ballasts that operate at 480 volts; and

(3) Metal halide lamp fixtures that use high-frequency electronic ballasts.

[[74 FR 12075](https://www.federalregister.gov/citation/74-FR-12075), Mar. 23, 2009, as amended at [79 FR 7844](https://www.federalregister.gov/citation/79-FR-7844), Feb. 10, 2014]