5. Lock washers or equivalent devices are provided for all bolts, screws, or studs that secure parts of the explosion-proof enclosures. All bolts, screws, and studs are in place and tightened.  

6. None of the fastenings used for joints on the explosion-proof enclosures are used for attaching non-essential parts or for making electrical connections.

7. Feeler gauges of the appropriate size are used to ensure that the clearances in all accessible flame path joints, between the enclosures and corresponding covers, are not exceeded.

8. Headlights are installed at each end of the machine and operable.