30 CFR § 28.20
Certificates of approval; scope of approval
July 29, 2020
(a) MSHA shall issue certificates of approval pursuant to the provisions of this subpart only for individual, completely fabricated fuses which have been examined, inspected, and tested as specified in §28.10, and have been evaluated by MSHA to ensure that they meet the minimum requirements prescribed in this part.
(b) MSHA shall not issue an informal notification of approval.