Recently our local authority having jurisdiction has indicated that they will not pass any installation where we have put our own knock out in a panel if it has factory knockouts. In other words any panel that has KO's on the bottom cannot be entered from any side or the top by punching a new hole as they say that it voids the UL listing.
We have been putting KO's in panels, pull boxes, and cans for years and it has never been an issue. Often times it is the only way to do an addition that results in a clean and safe installation.
Can anyone show me if this is a valid point? It seems that this is a ridiculous nitpicking stand from our local inspectors. I could understand if someone were to put a KO in the top of a N3R and then just stick a romex clamp or pipe fitting with just a locknut, but when the right parts are used I can't see where it should be a problem. The NEC is all about safety so why isn't a safe entry into a panel where it makes the cleanest installation OK??
We have been putting KO's in panels, pull boxes, and cans for years and it has never been an issue. Often times it is the only way to do an addition that results in a clean and safe installation.
Can anyone show me if this is a valid point? It seems that this is a ridiculous nitpicking stand from our local inspectors. I could understand if someone were to put a KO in the top of a N3R and then just stick a romex clamp or pipe fitting with just a locknut, but when the right parts are used I can't see where it should be a problem. The NEC is all about safety so why isn't a safe entry into a panel where it makes the cleanest installation OK??