It would be great if all of the KOs came out like the attachment shows. I have good luck removing the the center KO, then use the angled diagonal pliers to cut the next ring between the tabs on each side (180 degrees apart). Then each half can be removed without destroying the next ring.
Re: How to Remove Knockouts by NEMA#80907 06/11/0204:15 PM06/11/0204:15 PM
I raised the issue a few years back to a meter-socket manufacturing engineer [if here's any place that nipple/raceway lineup is not easy] and he mentioned that keeping sets of one-pass concentric punches and dies sharp is a pain and costs a lot of money for a year’s worth of stamping.
He seemed nice on the phone and followed up with a letter offering to quote ‘less knockouts and hub openings’ on quantities of 100+ sockets, provided, of course, no UL labeling was needed. (!) He balked at asking for three.
The same outfit did keep a good inventory of NOKO versions of cans and gutters, and I took advantage of that perk.
Re: How to Remove Knockouts by NEMA#80908 06/29/0212:51 PM06/29/0212:51 PM
I don't like KO's on meter sockets either. Once I had to repair a meter that someone had pushed in one of the KO's put in a very large firecracker, and shot the meter out into a lake. The once square meter socket was then round. We never found the meter.
I always use gutters with no KO's. They are readily available and easier to lay out.