SvenNYC,
check note 9 to Chap 9 Tables (pg 70-617 2002) ,i believe it alludes to nm and similar wiring, listings aside of course....
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Paul brings a point of interest,
(insignificant to this thread but of worthy mention) in that a 'channel' may not encapsulate 360 deg's as a conduit....so derating/conduit fill flys out the window...

[This message has been edited by sparky (edited 11-21-2002).]