【转帖】conduit knockou

yang686526

conduit knockout
is there a specific callout to use for conduit knockouts?
does anyone have a clean way to specify, lets say a half inch conduit knock out?
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do you need to show it on a manufacturing drawing so someone can build a part with a knockout in it, or just show that one exists on a layout?
mj,
it is an oem part.  the specification is for the sheet metal fab shop.
thanks,
dsgnr1
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not sure, but i think your .5 conduit knockout note will do. sheetmetal shop will use standard punch.
chris
sr. mechanical designer, cad
solidworks 05 sp0.1 / pdmworks 05
it has been pretty normal for me to see the knockout specified similar to a hole callout.
just give the measurable diameter followed by knockout and a direction in reference to the view, if it matters (1" knockout up). calling out the conduit size opens the door for confusion because a 1/2" conduit fitting does not use a 1/2" diameter knockout.  so are you passing a fitting through the knockout or just the conduit, hmmm.  
also if your knockout requires more specs than that, for ul or nema certification or something like that you should specify the complete criteria for the knockout as it is stated in the applicable standard, which has criteria for integrity of the knockout and possibly enviornmental issues (water tight, raint tight, dust proof...).
aamoroso
thanks for your reply.  you bring out some good info to ponder.  also, thanks for pointing out the direction that some enclosures take for certification.  at this time the req. for the enclosure are not to cert the box, however it will be considered.  i agree that good practice would be to anticipate what might happen if a requirement were deemed necessary.  i am not sure what nema spec (indoor) i would compare, but i get paid to look =).
thanks again,
dsgnr1
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we are a company involved in the manufacturing of emergency lighting and exit signage. i have worked with different enclosure type, .i.e. steel, plastic. whenever i need to emphasize to my supplier that i need a 1/2" conduit, i just simply write down on my drawing that this is a 1/2" k.o. with the specific direction.
you might want to check a free publication from nema on "enclosures" that has in-depth details on conduit knockouts: