As a general rule, the main reason for cable disconnects entering an enclosure is for portability where the machine has to be shipped in pieces, if it is one unit or to remain in one place then 1/2" conduit strain reliefs are commonly used, these are ordered with the right size rubber compression grommet at the time of order, they take from 1/4" to around 1/2" dia cables, you can obtain these from any electrical supply house, it is handy if you have access to a K.O. cutter to make the holes, these are a compression punch that goes from 1/2" to about 2" conduit size and make short work of making the right size holes.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.