29 CFR §1926.955

1. (a)General. Requirements for portable ladders contained in subpart X of this part apply in addition to the requirements of this section, except as specifically noted in paragraph (b) of this section.
2. (b)Special ladders and platforms. Portable ladders used on structures or conductors in conjunction with overhead line work need not meet § 1926.1053(b)(5)(i) and (b)(12). Portable ladders and platforms used on structures or conductors in conjunction with overhead line work shall meet the following requirements:
   1. (1)Design load. In the configurations in which they are used, portable platforms shall be capable of supporting without failure at least 2.5 times the maximum intended load.
   2. (2)Maximum load. Portable ladders and platforms may not be loaded in excess of the working loads for which they are designed.
   3. (3)Securing in place. Portable ladders and platforms shall be secured to prevent them from becoming dislodged.
   4. (4)Intended use. Portable ladders and platforms may be used only in applications for which they are designed.
3. (c)Conductive ladders. Portable metal ladders and other portable conductive ladders may not be used near exposed energized lines or equipment. However, in specialized high-voltage work, conductive ladders shall be used when the employer demonstrates that nonconductive ladders would present a greater hazard to employees than conductive ladders.