NM on Block wall

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Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
wbalsam1 said:
If the conduit length was over 24", of which these types of installations usually are, then why wouldn't 300.17 and 358.22 come into play? :smile:

300.17 talks about a raceway. A piece of conduit is not a raceway but a sleeve.

Suppose I ran an nm cable up a stud space for 8' and the insulators blow foam insulation and encapsulate my wire. Do I need to consider fill? I think not -- I know my example is not the same but in effect it is.

Perhaps this is more appropriate. I want to protect my wire coming down a wall so I install 2 runs of 3/8" plywood strips down the wall and use a piece of metal across the face of it. This is not a raceway but it is effectively the same. Is this a code violation?

Also Table 9 note 4 talks of 24" nipples between boxes, enclosure, and similar installations. This seems to verify my stance a bit more that fill is not counted in sleeves.

I realize this is an arguable code section but I do believe the use of Table 9 is meant for raceways.
 

76nemo

Senior Member
Location
Ogdensburg, NY
c2500 said:
That may be, but around here you would be out of business because you would not be able to compete with those running that crappy sleeved NM.

c2500


I agree with you there. I also agree with nakulak, any pipe work looks better than pipe and exposed combined. Yet, in reality of what c2500 states, running an entire garage in thinwall is alot more costly to the HO than using the combination.

As far as throwing a 2X4 up and strapping to it with NM, nooooo way, that's too hoky. Now, don't take that to heart, you see my signature!

I wouldn't run exposed in a garage, permitted or not. I'll sleeve it in thinwall up to the rafters and use the Arlington snap-ons on top if I can staple the NM within 12" of where it leaves the pipe, it's cheaper than buying the transition connectors.

If you are not an electrical junkie/fanatic, or an inspector, you'll never look "up" at the transition where it leaves the pipe, but you would notice the cheesy looking NM at face height if it was run exposed:cool:

You asked, I answered. Not worth much, but,.........you asked;)
 

wbalsam1

Senior Member
Location
Upper Jay, NY
Dennis Alwon said:
300.17 talks about a raceway. A piece of conduit is not a raceway but a sleeve.

Suppose I ran an nm cable up a stud space for 8' and the insulators blow foam insulation and encapsulate my wire. Do I need to consider fill? I think not -- I know my example is not the same but in effect it is.

Perhaps this is more appropriate. I want to protect my wire coming down a wall so I install 2 runs of 3/8" plywood strips down the wall and use a piece of metal across the face of it. This is not a raceway but it is effectively the same. Is this a code violation?

Also Table 9 note 4 talks of 24" nipples between boxes, enclosure, and similar installations. This seems to verify my stance a bit more that fill is not counted in sleeves.

I realize this is an arguable code section but I do believe the use of Table 9 is meant for raceways.

I can not find a single thing in the code to prove your interpretation wrong. No matter how much sense my argument may make to me, it is not supported by the code. Thanks for taking the time to clarify this for me. If I don't care for it, I always have the option of submitting a code change proposal. :smile:
 
Down here we sleeve the romex until it enters the hollow cell in the cinder block below the top course, which is poured solid. We sleeve it with carflex and it runs through the void in the block. We use cut in boxes for the devices.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
wbalsam1 said:
I can not find a single thing in the code to prove your interpretation wrong. No matter how much sense my argument may make to me, it is not supported by the code. Thanks for taking the time to clarify this for me. If I don't care for it, I always have the option of submitting a code change proposal. :smile:
You're welcome. I am not saying I like it either. Theoretically I could run 100' feet of conduit to sleeve a NM cable and just connect it with a rx conn. to the box and it's a sleeve not a raceway. Seems odd but there it is.
 

quogueelectric

Senior Member
Location
new york
My Question would be I heard somewhere that the stapling down of rx in a basement will not be allowed anymore it must be sleved.
Yet I also believe that the xsectional area or rx is determined by the wider side for derating and 3 wire might actually be thinner in this scenario.
I see both oposite oppinions here. I dont have a 2008 book yet.............. oh the shame.
 

quogueelectric

Senior Member
Location
new york
CHWflorida said:
Down here we sleeve the romex until it enters the hollow cell in the cinder block below the top course, which is poured solid. We sleeve it with carflex and it runs through the void in the block. We use cut in boxes for the devices.
Is this whats called a bond beam or is it a larger sized concrete beam poured around the top of the wall.??
 

electricalperson

Senior Member
Location
massachusetts
the way i do it is i run a piece of emt up and use an emt connector with a plastic bushing on the top and sleeve the romex down the pipe without stripping and strip it in the box like normal
 

tonyou812

Senior Member
Location
North New Jersey
electricalperson said:
the way i do it is i run a piece of emt up and use an emt connector with a plastic bushing on the top and sleeve the romex down the pipe without stripping and strip it in the box like normal
I used to do that too but Ive failed twice for it. the inspectors said that the cable is not supported properly. So now I just use a from too.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
NM on basement walls

NM on basement walls

As far as the 2008 Code is concerned, the following:

"(C) In Unfinished Basements and Crawl Spaces.............................
NM cable installed on the wall of an unfinished basement shall be permitted to be installed in a listed conduit or tubing or shall be protected in accordance with 300.4. Conduit or tubing shall be provided with a suitable insulating bushing or adapter at the point the cable enters the raceway. The NM cable sheath shall extend through the conduit or tubing and into the outlet or device box not less than 6 mm (? in.). The cable shall be secured within 300 mm (12 in.) of the point where the cable enters the conduit or tubing. Metal conduit, tubing, and metal outlet boxes shall be connected to an equipment grounding conductor. "

most of which is marked as a "change"
 

iaov

Senior Member
Location
Rhinelander WI
I use EMT. Its easy and it looks good. I don't know the article off hand but I believe you have to have a fitting where it comes up into the rafters/ cieling joists. Not a bushing.
 

stickboy1375

Senior Member
Location
Litchfield, CT
iaov said:
I believe you have to have a fitting where it comes up into the rafters/ cieling joists. Not a bushing.

When you find it let us know... :wink: IMO, a snap on bushing is a fitting, so as long as I have a staple within 12" i'm good.
 

76nemo

Senior Member
Location
Ogdensburg, NY
iaov said:
I use EMT. Its easy and it looks good. I don't know the article off hand but I believe you have to have a fitting where it comes up into the rafters/ cieling joists. Not a bushing.


Not if it is secured within 12" after leaving the pipe. That's why I stated the Arlington snap-on's are cheaper than the transition connectors. The top of the pipe must utilize a bushing, but only HAS to be secured within 12" there after.
 

blue spark

Senior Member
Location
MN
OK, so my inspector is misinformed and I'm glad. Up here alot of builders fir out their concrete walls with 2x2s and insulate between. IMO, if your running NM which is all we do in resi, I'll sleeve it in EMT. I can't believe there is so much misinformation on this subject. Also in ICF basements, we do the same. Arlington makes a white EMT bushing for the top entrance to the pipe in 1/2 and 3/4.
 

stickboy1375

Senior Member
Location
Litchfield, CT
blue spark said:
Up here alot of builders fir out their concrete walls with 2x2s and insulate between. IMO, if your running NM which is all we do in resi, I'll sleeve it in EMT.


I just use tyraps with holes in them and use tapcons to fasten to the concrete... quick and easy.
 

quogueelectric

Senior Member
Location
new york
augie47 said:
As far as the 2008 Code is concerned, the following:

"(C) In Unfinished Basements and Crawl Spaces.............................
NM cable installed on the wall of an unfinished basement shall be permitted to be installed in a listed conduit or tubing or shall be protected in accordance with 300.4. Conduit or tubing shall be provided with a suitable insulating bushing or adapter at the point the cable enters the raceway. The NM cable sheath shall extend through the conduit or tubing and into the outlet or device box not less than 6 mm (? in.). The cable shall be secured within 300 mm (12 in.) of the point where the cable enters the conduit or tubing. Metal conduit, tubing, and metal outlet boxes shall be connected to an equipment grounding conductor. "

most of which is marked as a "change"
Thanks that is what I was asking about yet also the fill has been changed to the wide dimention of the flat nm I think which could be counter productive unless it was 3/4 pipe.
 
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