Elk Structured Box Knockout Sizes

[SteveS]

Hi,
 
I'm afraid this may be a dumb question but I'm puzzled about the knockouts on the 14" box that came with my ELK M1 Gold (ELKM1GSYS4) .  The knockouts on the top and bottom appear to have two sizes (1" and 1.5") but for the knockouts on the top it looks like only the 1" are partially opened while on the bottom only the 1.5" are partially open.
 
Is this correct or is the paint obscuring the other sized knockouts?  It isn't a big deal but I was hoping to use the same size knockout on the top (for most of the sensor and keypad wires) and the bottom (for the input power).
 
thanks,
Steve

 

[RAL]

I'm not sure what you mean by "partially opened."   On my enclosure, some of the knockout rings are punched all the way through the metal, most of the way around, except for two tabs about 1/8" wide that hold the knockout in place.  But other knockouts are not punched completely through, making them appear solid all the way around.  If that's what you mean by partially opened, then, yes that's normal.
 
The knockouts on the top and bottom are for 1/2", 3/4" and 1-1/4" fittings, so there are 3 metal discs/rings.   Each one is secured by one or two tabs that are not punched through.  It can be a little tricky to remove the innermost 1/2" knockout without disturbing the 3/4" knockout, since the 3/4" knockout ring may want to give way more easily than the 1/2" knockout.
 
Find the attachment tab on the knockout you want to remove, and use a screwdriver to pry it open at a point away from the tab.  Then use pliers to work it back and forth until it breaks free.
 
Here are some tips on how to remove them.
 
http://www.wikihow.com/Remove-a-%22Knock-Out%22-from-an-Electrical-Box

 

[Del91574]

As a pro, the double KO's are sometimes problematic (IE: need 1/2 but 3/4" comes out when you hit it) and a good hole saw or unibit are easier in the long run.