Yeah we all have made boxes like that and I bet we all have seen them missing KOs.
You need a box listed for pendant use, this box will have a threaded hub for the Kellem Grip and will have no other KOs.
Be happy the OSHA guy did not fine the heck out of your customer.
The box will look similar to this one
![[Linked Image from appletonelec.com]](http://www.appletonelec.com/gif/bFSFDsingle.gif)