Ground wire entrance clamp

[gumbudah]

I have a number 4 stranded bare wire to run into my main panel for grounding. I live in wisconsin, what is the "right" way to penetrate through the panel wall? I see there is a 3/8" or so hole in the panel wall would fit perfect through... use one of the 1/2" knock outs and NM entrance clamp? other type of entrance connector/clamp? nothing? does it matter?

 

[Aceman]

I drill a 5/16 hole wherever I need too. You don't have to come through a KO.

 

[BigJohn20]

What aceman says.

There are compression fittings for ground wires (forget the manufacturer at the moment) but IMHO they seem like they're just a money grab.

 

[jeffmoss26]

Bridgeport makes a fitting that goes inside a 1/2 inch KO with a locknut and secures the ground wire with a set screw.