# column-width panelboard



## Zaped (Jul 6, 2008)

In the quoted NEC excerpt below, that refers to a 'column-width panelboard', WHAT IS A COLUMN-WIDTH PANELBOARD ?
= = = = =

QUOTE(from NEC):
300.3-B

(4) Enclosures Where an auxiliary gutter runs between a column-width panelboard and a
pull box, and the pull box includes neutral terminations, the neutral conductors of circuits
supplied from the panelboard shall be permitted to originate in the pull box.

(Handbook Commmentary: Section 300.3(B)(4) recognizes the practice of supplying narrow, column-type panelboard through an auxiliary gutter from an overhead pull box and running only the ungrounded conductors down from the pull box to the panelboard. As shown in Exhibit 300.1, the feeder and branch-circuit neutral conductors are terminated in the overhead pull box and are not carried with the ungrounded conductors. Inductive heating does not occur, because the load-carrying conductors extend down and back up within the
same enclosure.)


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## stuiec (Sep 25, 2010)

slim panel like this?

View attachment 22142


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## GEORGE D (Apr 2, 2009)

Heres one I posted a while back, it was my first time ever encountering one. 


http://www.electriciantalk.com/attachments/f30/14300d1338383963-skinny-panel-image-2122472952.jpg


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## frenchelectrican (Mar 15, 2007)

I have ran into column width panel board pretty often in few locations so there are few thing you will have to remember is the netural / ground connections will be at the upper junction box but for the phase conductor you can run all way down to the breaker.

I know few industrial customer of mine do use both 208Y120 or 120/240 SP panel on one side of beam while the other side is 480Y277 so it pretty common to do that and btw the transfomer is sited up pretty high and not very large useally 15 or 30 KVA depending on the load it will be used.

Merci,
Marc


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## chicken steve (Mar 22, 2011)

All our old mills were _lousy_ with them here

Some of those mills had larger floor area's than football fields

but the story i get from old timers is, it wasn't so much a space issue, as it was a safety one isolating the OCPD's from the flurry of production, fork lifts, etc

~CS~


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## drumnut08 (Sep 23, 2012)

Zaped said:


> In the quoted NEC excerpt below, that refers to a 'column-width panelboard', WHAT IS A COLUMN-WIDTH PANELBOARD ?
> = = = = =
> 
> QUOTE(from NEC):
> ...


I had a maintenance contract at an old big warehouse , that had these panels all throughout the building . In most cases one side of the column had a 277/480 v panel , the other side had a 120/208 v panel . The step down xfmr was mounted safely up high on the column . There was a wire way ( same dimensions as panelboard ) that extended up to the ceiling , which housed the panel feeder and branch circuits . These were devised mainly to keep from getting destroyed by forklifts and to keep load shedding capability closer to the end users fingers . In a huge place where the exterior walls are know where near the equipment , it made sense .


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## Going_Commando (Oct 1, 2011)

I hate those things. They are so damned cramped to work in, and like Steve said, they are everywhere in older mill buildings in New England. When I was doing a job at a mill complex (12 attached buildings built over time), there were probably 20 of those things scattered around the place.


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