Originally Posted By: Greg Fretwell
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Spencer, you have to be careful taking things out of context in the NEC.
You have to read the whole article. If I was to take the “junction box” rule out of context completly I would also say you couldn’t splice the neutral in a box containing a snap switch!
"312.8 Enclosures for Switches or Overcurrent Devices.
Enclosures for switches
or overcurrent devices shall not be used as junction boxes ... <auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices>
We know that is not true so we must read on
"...unless adequate space for this purpose is provided. The conductors shall not fill the wiring space at any cross section to more than 40 percent of the cross-sectional area of the space, and the conductors, splices, and taps shall not fill the wiring space at any cross section to more than 75 percent of the cross-sectional area of that space."
That leaves a lot of wiggle room, to much for Joe T, who wants to change it. Realistically you can splice a conductor in a panelboard enclosure and it takes an inspector who is making up his own rules to say you can't.
The intent is that the conductors in an enclosure only serve the devices inside but it doesn't even hint that you can't splice a conductor serving one of those devices.
Where the issue comes up is when you are routing a feeder or service conductor to another cabinet through this one. It is still legal as long as you have sufficient space. In fact the IAEI just had that question in the magazine a month or so ago.