(a)
- (1) Couplers that are used in medium- or high-voltage power circuits shall be of the three-phase type and enclosed in a full metallic shell, except that the Secretary may permit, under such guidelines as he may prescribe, no less effective couplers constructed of materials other than metal.
- (2) Cable couplers shall be adequate for the intended current and voltage.
- (3) Cable couplers with any metal exposed shall be grounded to the ground conductor in the cable.
- (4) Couplers shall be constructed to cause the ground check continuity conductor to break first and the ground conductor last when being uncoupled when pilot check circuits are used.
- (b) Cable connection boxes shall be of substantial construction and designed to guard all energized parts from personal contact.