2" pvc 24"long above panel thru top plates for cable entry

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Does nec 312.5 (C)(2) prohibit a raceway for cables from going into an attic? It says penetrate a structural ceiling. Does going thru the top plates of a wall without going thru a ceiling joist or sheet rock still penetate a strucrural ceiling?
 
I'm working on a residential wiring course and don't want to misinterpret the code. I see this alot as a spare conduit for future panel entries
 

infinity

Moderator
Staff member
Location
New Jersey
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Journeyman Electrician
Does nec 312.5 (C)(2) prohibit a raceway for cables from going into an attic? It says penetrate a structural ceiling. Does going thru the top plates of a wall without going thru a ceiling joist or sheet rock still penetate a strucrural ceiling?
Top plates of the wall imply that the panel is recessed, 312.5(C)Ex. is for surface mounted panels only.

312.5(C) Cables. Where cable is used, each cable shall be se-
cured to the cabinet, cutout box, or meter socket enclosure.
Exception: Cables with entirely nonmetallic sheaths shall be permitted to enter the top of a surface-mounted enclosure through one or more nonflexible raceways not less than 450 mm (18 in.) and not more than 3.0 m (10 ft) in
length, provided all of the following conditions are met:
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
I believe 312.5(C) is referring to open ended conduits only, not complete raceways. AFAIK it's legal to run conduit from a panel (emanating from the top, side, bottom, or back; surface-mounted or flush) through a structural ceiling as long as it terminates in j-box, panel, trough, or other approved container.
 
Top plates of the wall imply that the panel is recessed, 312.5(C)Ex. is for surface mounted panels only.
You are correct. I didn't see that. I guess this would have to be residential only since romex can't be run exposed in commercial buildings even above dropped ceilings. If it can't go through the ceiling, when would you do this? Ugly
 

kwired

Electron manager
Location
NE Nebraska
I believe 312.5(C) is referring to open ended conduits only, not complete raceways. AFAIK it's legal to run conduit from a panel (emanating from the top, side, bottom, or back; surface-mounted or flush) through a structural ceiling as long as it terminates in j-box, panel, trough, or other approved container.
Might want to read it again and post your thoughts afterward, in particular the exception's main content plus condition (b).;)
 
Might want to read it again and post your thoughts afterward, in particular the exception's main content plus condition (b).;)
I have reread this execption. I believe it is referring to nonmetallic sheath cable such as Romex directly entering a nonmetallic conduit such as PVC to gain entry into a surface mounted enclosure without the conduit penetrating a structural ceiling. Romex can be exposed in dwellings. But who would ever run such a cable (s) into conduit before entering an enclosure unless the conduit was rUn through the ceiling into the attic for ease of entry. Why would you take an exposed conduit up to 10 feet away from the top of a panel. Maybe to go into a,structual wall to provide access to romex in the wall? Seems like it would be better to have a box at the end of the conduit. Help me see the logic of this code.
 

jap

Senior Member
I have reread this execption. I believe it is referring to nonmetallic sheath cable such as Romex directly entering a nonmetallic conduit such as PVC to gain entry into a surface mounted enclosure without the conduit penetrating a structural ceiling. Romex can be exposed in dwellings. But who would ever run such a cable (s) into conduit before entering an enclosure unless the conduit was rUn through the ceiling into the attic for ease of entry. Why would you take an exposed conduit up to 10 feet away from the top of a panel. Maybe to go into a,structual wall to provide access to romex in the wall? Seems like it would be better to have a box at the end of the conduit. Help me see the logic of this code.
They are not talking about stubbing the conduit into the wall.

The rule does have it's uses and advantages.

Picture a surface mount panel in the basement.

Think of the PVC conduit (if that's what you're going to use) as a stub up stopped just short of the ceiling.

This allows NM to be run exposed up high and the use of the chase to get the cables down into the panel.

Beats the heck out of having to use multiple more staples staples down the wall and several romex connectors.

JAP>
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
I have reread this execption. I believe it is referring to nonmetallic sheath cable such as Romex directly entering a nonmetallic conduit such as PVC to gain entry into a surface mounted enclosure without the conduit penetrating a structural ceiling. Romex can be exposed in dwellings. But who would ever run such a cable (s) into conduit before entering an enclosure unless the conduit was rUn through the ceiling into the attic for ease of entry. Why would you take an exposed conduit up to 10 feet away from the top of a panel. Maybe to go into a,structual wall to provide access to romex in the wall? Seems like it would be better to have a box at the end of the conduit. Help me see the logic of this code.
Well, one specific instance where this applies is outdoor surface mounted panels. In new construction you could run the branch circuit wiring out the back of the panel and through the block wall to get inside. When the panel is added as an upgrade (usually on older homes with very small panels or fuse boxes), the easiest way to run the branch circuit wiring is through a sleeve connected to the top of the panel. The sleeve stops short of the eave and the cables fan out and are fastened to a wood strip before entering the attic through the eave. A metal cover is placed over this which runs from the eave down toward the panel stopping short of the top of the panel (you can see the sleeve(s)). The last one I did required three sleeves to avoid derating issues. Also all the cables had to be UF per the inspector since I was unsuccessful in convincing him it was a dry area where NM could be used.

ETA: Why use the sleeves at all? You want to minimize the number of penetrations into an outdoor panel and the specialised connectors you would need to keep it raintight.
 
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Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
Might want to read it again and post your thoughts afterward, in particular the exception's main content plus condition (b).;)
I guess I'm being dense. I reread the article and I don't see anything to change what I said. Please specifically point out what you think I'm misstating.
 

jap

Senior Member
I guess I'm being dense. I reread the article and I don't see anything to change what I said. Please specifically point out what you think I'm misstating.
The rule only applies to surface mount panels and it cannot go through a structural ceiling.

JAP>
 

jap

Senior Member
Well, one specific instance where this applies is outdoor surface mounted panels. In new construction you could run the branch circuit wiring out the back of the panel and through the block wall to get inside. When the panel is added as an upgrade (usually on older homes with very small panels or fuse boxes), the easiest way to run the branch circuit wiring is through a sleeve connected to the top of the panel. The sleeve stops short of the eave and the cables fan out and are fastened to a wood strip before entering the attic through the eave. A metal cover is placed over this which runs from the eave down toward the panel stopping short of the top of the panel (you can see the sleeve(s)). The last one I did required three sleeves to avoid derating issues. Also all the cables had to be UF per the inspector since I was unsuccessful in convincing him it was a dry area where NM could be used.

ETA: Why use the sleeves at all? You want to minimize the number of penetrations into an outdoor panel and the specialised connectors you would need to keep it raintight.
NM should never be used in the same sentence along with eaves and outdoor.

The inspector was correct.

NM is not rated for such locations.

JAP>
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
But who would ever run such a cable (s) into conduit before entering an enclosure unless the conduit was rUn through the ceiling into the attic for ease of entry. Why would you take an exposed conduit up to 10 feet away from the top of a panel.
Regularly done in warehouse-type installations.
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
NM should never be used in the same sentence along with eaves and outdoor.

The inspector was correct.

NM is not rated for such locations.

JAP>
I contend it is a dry location because the cable can't get wet. I doubt it could even get damp. It's fully covered by pipe, or a metal chase or both. Yes, it's entering the eave, but there is a weatherproof cover over it. The inspector did not agree with me, but that is my argument and I still think I'm right.

BTW, He said if I built a box around it and stucco'ed the box, NM would be OK. Not sure what the difference is.
 
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Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
The rule only applies to surface mount panels and it cannot go through a structural ceiling.

JAP>
Yes, 312.5(C) applies only to surface mount panels. However, if you are running conduit in the standard fashion of connecting it on both ends to a box, 312.5(C) does not apply and you can run the conduit where ever you want including thru a structural ceiling. If you reread my post you will see that is what I was saying.
 

DrSparks

Senior Member
Location
Madison, WI, USA
The rule only applies to surface mount panels and it cannot go through a structural ceiling.

JAP>
Wisconsin SPS 316 electrical code overrides this. We are allowed to sleeve Romex from a surface mounted panel through a structural ceiling into the Attic or through the floor into the basement

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nickelec

Senior Member
Location
US
In these parts we really only use RMC coming out of the meter if it's outdoors. Inside we use emt

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