classification of wiring duct in control panel

[j_braddock]

i was walking through the plant and ended up helping one of our maintenance workers.

he was tracing some wiring in a control panel and had to remove the cover off some panduit wiring duct. it was packed full. it took both of us to put the cover back on the wiring duct.

i know that there is a 40% fill on conduits and wire troughs, but i do not know what the classification of wiring duct is inside a control panel and the accepted fill capacity.

thank you in advance for your help.

 

[bthielen]

Re: classification of wiring duct in control panel

Hope this helps.

NFPA 79 for industrial machinery, 14.5.2, states that the combined cross-sectional area of all conductors and cables shall not exceed 50% of the interior cross-sectional area of the raceway (duct). The fill provisions shall be based on the actual dimensions of the conductors or cables used.

Bob

 

[j_braddock]

Re: classification of wiring duct in control panel

bob,

i have the 97 version - electrical standard for industrial machinery, please verify your answer.
i do not have a scetion 14.5.2

found it by accident.
97 version section 17 - raceways,junction boxes, and pull boxes. 17.2 - Percent fill of raceways.
"the combined cross-sectional area of all conductors shall not exceed 50 percent of the interior cross-sectional area of the raceway. the fill provisions shall be based on the actual of the conductors or cables used."

thank you for your efforts.

[ July 10, 2003, 05:31 PM: Message edited by: j_braddock ]

 

[jim dungar]

Re: classification of wiring duct in control panel

The slotted wiring channel used for conductor support inside of the panel is not a raceway and not subject to the 50% fill (NFPA79-1997 3.70, ...raceway: An enclosed channel...,). Section 17 only applies to wiring and raceways external to the panel (NFPA79-1997 16.3.1).

However, I do wish NFPA 79 was required instead of optional.