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#84105 - 03/10/03 02:54 PM Bundled wiring?  
Reel-Break  Offline
Joined: Apr 2002
Posts: 178
Can someone please give some advise on this.Running wiring through holes in a web beam floor joist.I don`t have them packed but I have 4- 14/2 cables in some and 12/2 and 10/3 in others and ahj says I`m bundling must derate.I thought they had to be tied or taped. Thanks

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#84106 - 03/10/03 05:00 PM Re: Bundled wiring?  
sparky  Offline
Joined: Oct 2000
Posts: 5,311
'bundeling' is somewhat ill-defined, 310.15(b)(2)ex 5 can be used if your running MC or AC.

Table 310.15(b)(2)(a) w/310.16's ability to start @ the 90 deg collum should grant you some leverage

#84107 - 03/10/03 06:03 PM Re: Bundled wiring?  
Tom  Offline
Joined: Jan 2001
Posts: 1,044
Shinnston, WV USA
If all you have is four 2 wire cables, there is no problem. You will be derating to 70% of the 90 degree column.

The trouble starts when you hit the fifth 2 wire cable in the bundle which requires a 50% derating.

As for the 3 wire cables, if this is a single phase system, the neutral is not considered a current carrying conductor and if this is a 3 way switch cable, only 2 wires are current carrying.

Few things are harder to put up with than the annoyance of a good example.

#84108 - 03/10/03 07:46 PM Re: Bundled wiring?  
George  Offline
Joined: Feb 2002
Posts: 375
Only if the joist holes are longer than 2' does the derating apply.

It is between you and your inspector as to what you will agree on.

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