wire capacity 2" pvc conduit

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  #1  
Old 01-31-05, 08:23 AM
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wire capacity 2" pvc conduit

Wondering if my main panel needs another conduit added before any new circuits added... Exterior 125A panel has a single 2" PVC conduit exiting it to basement. It's not entirely packed, but seems pretty tight, am even wondering if it's already too full?

Contains (roughly, from memory): 4 #6 to sub-panel, 4 #6 to a/c, 6/3 to range, 8/3 to small sub upstairs, 2 #6 to ground electrodes, 12/2 to exterior outlet.

The panel only has 3/4 and 1" holes remaining in the bottom, the only other 1-1/2 / 2" hole is on the side near the bottom. If need to add conduit, would it be wiser to just have the 2" installed on the side so that won't ever have to worry about this again? (rather than starting a potential mess of smaller conduits out the bottom?)
 
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Old 01-31-05, 08:43 AM
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also, forgot, contains another 8/3 for dryer
 
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Old 01-31-05, 08:53 AM
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How long is this 2" conduit?
 
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Old 01-31-05, 09:30 AM
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Originally Posted by Jedi9
How long is this 2" conduit?
About 2-1/2 feet (approx, from memory) just from bottom of panel down to where it enters siding into basement between floor joists.
 
  #5  
Old 01-31-05, 11:15 AM
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If the conduit doesn't exceed 24" than no derating is nec and you can pack it. If it does exceed 24", I would recommend putting in another conduit.
 
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Old 02-01-05, 08:27 AM
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Originally Posted by Jedi9
If the conduit doesn't exceed 24"
Boy, it's right there... The length of the 2" pvc, is *exactly* 24", as if someone were pushing the code to its absolute limit. But that doesn't include the male adapter at the panel, and an access box L at the bottom, then another short segment of 2" through the wall. I guess it depends on how the code is worded exactly, whether or not that's acceptable (measured by whole enclosed run, or by straight runs between "open" access points). It seems like any additional wiring ought to have a new conduit if it's that close already, right?
 
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Old 02-01-05, 10:30 AM
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Yes, put in another
 
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Old 02-01-05, 10:41 AM
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Actual code says derating factors shall not apply to conductors in nipples having a length not exceeding 24". I don't know why its written like that instead of total conduit length not to exceed 24", so theoreticaly you are ok, it would be up to authority having jurisdiction to make the call. But I would add another.
 
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Old 02-03-05, 09:53 AM
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Actually.....not correct......Their is FILL requirements

Togo,

Becareful here......the derating refers to TEMPS and Adjustments but you still have a FILL factor even in nipples regardless of the length....

Chapter 9 Tables Notes ( 4) 60% fill so you can't simply " JAM IT UP " as suggested....you still have heat build up and induction and so on as the derating has NOTHING to do with the fill....has to do with the TEMP.....

For goodness sakes don't just PACK IT.....you need to know the fill as it can't exceed 60% fill for nipples that do not exceed 24 inches...

As a instructor I had to comment on this........you are still bound by the rules of FILL.....only the TEMP derating is excused from this calculation...

Please read the Chapter 9 Tables Note : 4..........
 
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Old 02-03-05, 11:22 AM
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Yes, but the fill rules only apply to complete conduit systems. A 24" segment of conduit with an open end certainly is not a complete conduit system.
 
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Old 02-03-05, 11:30 AM
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Is it NOT connected from the panel to something.....or is it just a stub down.....

I figured it was connected............ahhh...just a STUB....


See thats why we need the edit feature...lol........still I dont like the idea of PACKING a conduit to its max.......still a issue of heat build up and surface area and so on.....

But hey.......I thought it was full connection......need to clear that up as I would not generally tell someone to fill away...lol...it could be too tight and cause a jacket to be ripped and so on trying to force another inside it....

Ahhh.....John is refering to the protection issue.....then Table 1 does not apply....I thought you were trying to do a fill on a conduit .....man you are saying a 24" piece is going from the panel and that is long enough to get from the panel to the basement.....wow....first I have seen that one..

This is why I figured it was a true nipple to something....lol
 
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Old 02-03-05, 11:35 AM
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Originally Posted by Togomor
But that doesn't include the male adapter at the panel, and an access box L at the bottom, then another short segment of 2" through the wall. I guess it depends on how the code is worded exactly, whether or not that's acceptable (measured by whole enclosed run, or by straight runs between "open" access points). It seems like any additional wiring ought to have a new conduit if it's that close already, right?

The LB would it not be considered a complete run even if it continues through the wall.....the fill also applies to the LB as well so I personally would think it is not open with the LB and then into the wall.....

Hey.......you learn something new every day...personally I am not PACKING it to its fill...
 

Last edited by John Nelson; 02-03-05 at 01:53 PM. Reason: fix vBcode
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Old 02-03-05, 11:55 AM
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hmmmm.....personally I am not sure I like the idea of my posts being edited....Enough of my advice...I am out of here....Have a good time everyone and best of luck....Dont shock yourself !
 
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Old 02-03-05, 12:02 PM
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Its common practice here where you have a crawl space, no basement, to come out of the bottom of the panel and LB it through the foundation. No, I definetley don't advocate cramming it to the point of insulation damage. I don't think you would get to 60% before it got pretty tight, if you could get the area of the cable to start with.
 
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Old 02-03-05, 12:10 PM
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Originally Posted by Togomor
Wondering if my main panel needs another conduit added before any new circuits added... Exterior 125A panel has a single 2" PVC conduit exiting it to basement. It's not entirely packed, but seems pretty tight, am even wondering if it's already too full?

No worries jedi......here in VA we look at this as a complete system if the wire is not stubed straight down...in this case it was run to a LB which has a fill requirement ( usually stamped on the LB ) and then into the basement...so he indicates he has a basement...

I know what you mean...Just did not want someone reading it and jaming wires in pipes....lol...can you imagine someone doing that..I can...

The issue is what is complete...because once end of the pipe is connected to the panel...and the other to a LB....not just stubbed down into a basement as protection...so someone ( local AHJ ) could pull a raw deal and say the fill must apply......because it terminates in two different boxes or enclosures...just because the small end from the LB to the basement is open does not religate the portion from the Panel to the LB.....

Just wanted to chime in on it.......meant nothing by it......anyway here because of the panel height.....a 24" would never get us into the basement..lol but again we dont do many exterior panel installs either so I guess it is totally possible....

I can just see a AHJ inspector having a bad day and saying....fella that LB is a enclosure..lol....you have to account for fill in that piece between the panel and the LB....lol......
 

Last edited by John Nelson; 02-03-05 at 01:52 PM. Reason: fix vBcode
  #16  
Old 02-03-05, 02:46 PM
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You guys are getting way above my head, I don't even know what an "LB" is , though I enjoy the discussion anyway. Here's what I've taken from it, from my original 2 questions:

1. new work: is existing conduit full enough that a new conduit should be added for any new circuits
A. yes

2. old work: is existing conduit already SO full as to be in violation
A. probably not

For any wanting more info: My use of "basement" probably should have been "crawl space". What I have is 125A panel with center of meter at about 68" above ground, from bottom of panel 2" male adapter, 24" length 2" PVC, L access box, 4" length 2" pvc through wall, then open to air with wires poking out in crawl space then stapled along floor joists along several different paths.

Thanks to all for your help.
 
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