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All the main breaker boxes I could find had top or bottom feed entry from the service meter can. Besides being a pain to work with, is there anything wrong with drilling a 2" hole on the side of the panel where my lb box is to enter the panel with main feed wires?

I'm not sure how the wires will bend, but once they do there is plenty of room at the bottom of the panel to go up into the lugs.

The 2" hole will have sharp edges, but after installing the threaded Union and nut, there will be no sharp edges.

  • I think bending radius will likely be a problem, unless the panel is quite large. What enclosure are you specifically looking at, and what size/type are the feeder conductors? – Tester101 Aug 14 '17 at 13:49
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You can put a hole in a NEMA-1 enclosure, but if it is a NEMA 3R (raintight, outdoors) the conduit entry must be able to maintain the N-3R rating. The most common fitting is called a Myers Hub. This assures you from dripping water on live parts and that's why KO's are at the bottom and lower sides. Also any sharp edge must be bushed. I'm assuming that's you "threaded union" (not an electrical term).

As far as bending radius of conductors here's a link that may help. http://www.cooperindustries.com/content/dam/public/bline/Resources/Library/catalogs/meter_mounting_equipment/ring-type_metering/ed-minimumwirebendingspace.pdf

Its Tables 312.6 (A) & (B) of the NEC.

There's also NEC rules for conduit entry and bending radius that is Article 314.28 pretty much the whole thing. It may not be directly relevant but should be looked at for verification.

  • Yes, this is indoors so NEMA-1. Size 2" Conduit, 4/0 4/0 2/0 aluminum. If the wire is able to make a bend in the LB box, I believe that is similar amount of space to be had when entering the side of the 200Amp panel. It will come in, bend 90 to go down, and then can gradually bend up into the lugs. If this bend doesn't work, can there be an open hole in the panel? With a threaded cap on the end of the bushing, of course. In which there would need to be some kind of flex conduit going into the bottom which I believe would not be code compliant. I really wish the service entry was 1' lower. – Nic Aug 14 '17 at 15:54
  • I think what your are trying to say is that you're trying to punch a hole and put in an LB at the top of a N-1 box then bend the conductor around. That is ok. Then you're saying if I can't bend the conductors around inside the enclosure, is it alright to use a piece of flex, attach it to the conduit then bring the service conductors up into the lugs from the bottom of the enclosure. If that is what you are saying you can do that too. I always use a piece of sealtite for rigidity and protection. Just make sure you're not in an area where the sealtite could be damaged. – Retired Master Electrician Aug 14 '17 at 19:18
  • The LB is to the left of the panel. Conduit enters the house, and I immediately slap an LB onto that conduit to get a 90 degree bend to enter my panel. Once inside the panel I would have to bend the wires again to get them to point down, in which they would go down and then bend up to tie into the lugs which are at the bottom of the panel. As far as I know, I would not be allowed to use flex to enter the panel at the bottom because flex is not rigid and it's also not located very high. – Nic Aug 15 '17 at 16:13
  • OK lets make a clarification. NEC Article 350.12 (1) states LFMC (sealtight) may not be used "Where subject to physical damage". But NEC Article 230.43 (15) states LFMC can be used to install service conductors in lengths 6 ft or less. So use your own discretion. – Retired Master Electrician Aug 15 '17 at 19:39
  • So what would one consider subject to physical damage? Interior of a basement, but exposed to people in the basement? I suppose that's dependent on the inspector's opinion. Would be nice to just email you the photo. – Nic Aug 16 '17 at 15:28

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