Maximum fill for conductors in a panel board

[Wendell Swedberg]

Okay, today's test question:

The maximum fill permitted for conductors, excluding splices and taps, in a panelboard is limited to what maximum percent?

a) 10
b) 20
c) 40
d) 75

Answer is (C)-40......I can't find out how this is being derived.

Thanks.

Wen

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[Jerry Peck]

From the 2006 IRC. (underlining is mine)
- SECTION E3807
- - CABINETS AND PANELBOARDS

- - - E3807.1 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, except where 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.

[Jerry McCarthy]

So Jer, you would consider this overfill according to the code?

[Jerry Peck]

WC Jerry,

Nah, I see some splices in there, so that can go to 75% ... that's not over 75% is it?

(Way over 75%. )