The Crouse Hinds Heavy Duty Arktite Electrical plugs are designed for industrial use and are very solid built and designed to be pulled under load . That's why their so popular for portable pumps etc that are operating at 480 volts 3 Phase Delta Service. Where a dangerous arc Fault can develop when you pull out the plug when its under load these plugs are designed to prevent that from happening.
However they have an Achilles heal as we have found out at an Oil Distribution Facility.
They whole upper assembly which contains the pin sleeve components is held in place with one set screw seen below
What happened at our facility the screw fell out either from use or not being installed properly fell out and allowed the inner pin sleeve to rotate and pull wires loose . The how wires made contact to each other and their was a loud bang breakers tripped but the arc stayed contained as designed.
They really need 2 screws to make sure the inner sleeve will not accidently rotate.
