How many current carrying conductors can you have coming from a trough to a panel. My boss says that it doesnt matter the size of trough or the pipe that you can only have 24 current carrying conductors and 10 wires. Is this true for the new code?
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Never heard of this rule. While it is a good idea to avoid overcrowding your wiring structures, this in particular isn't an official rule. Maybe a local rule or a job specification.
In nipples that are 24" length and less, you don't need to think about number of wires bundling derate. And, while it is not something I'd advise, you are permitted to fill nipples that are 24" and less to up to 60% fill. I generally would recommend trying to meet the sizing rules for raceway sizes in general, just in case the segment ends up being longer than 24". And it will fit much better.
In wireways and wire troughs, you do have something interesting happen at 30 wires. For 30 current-carrying conductors and less, you can ignore bundling derates. Once you put your 31st current-carrying wire in the wireway, you now have the derate that applies for 31 wires. 40% in the NEC, or where I live in Massachusetts, the local code overrides it, allowing a 60% derate factor at 31 wires.