; and (ii) supervises the work performed with grant funds. (B) Volunteer labor A volunteer who performs work for a covered organization that receives a grant under section 414C shall not be required to be certified under this subsection if the volunteer is not directly installing or repairing mechanical equipment or other items that require skilled labor. (C) Training The Secretary shall use training and technical assistance funds available to the Secretary to assist covered organizations under section 414C in providing training to obtain certification required under this subsection, including provisional or temporary certification. (3) Minimum efficiency standards Effective beginning October 1, 2017, the Secretary shall ensure that— (A) each retrofit for which weatherization assistance is provided under this part meets minimum efficiency and quality of work standards established by the Secretary after weatherization of a dwelling unit; (B) at least 10 percent of the dwelling units are randomly inspected by a third party accredited under this subsection to ensure compliance with the minimum efficiency and quality of work standards established under subparagraph (A)