Is this code compliant?

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Transportation Guy

Senior Member
Location
Williamsburg,VA
We are wiring a new hotel. The attached picture is what the AHJ in another state allowed. We didnt think out local would accept this because the ENT in the concrete doesnt terminate in the box. Thoughts?

We decided to extend the ENT you see recessed in the concrete with ENT and terminate it in the bottom of a can like this one. On the bottom of the can, we plan to add a coupling and run EMT down to the panel. Basically utilize a trough to house the ENT extensions where they cant be seen and then build a strut rack for the EMT below the trough. Local said he didnt think it would be code and will "get back to us". Thoughts?
 

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Smart $

Esteemed Member
Location
Ohio
I'd comply with 362.46 and call it a day...

362.46 Bushings. Where a tubing enters a box, fitting, or
other enclosure, a bushing or adapter shall be provided to
protect the wire from abrasion unless the box, fitting, or
enclosure design provides equivalent protection.
 

Transportation Guy

Senior Member
Location
Williamsburg,VA
So a topless enclosure would be the same as a bottomless? With a bushing on the ent, branch circuit conductors running into the box as shown, into EMT that is terminated into the bottom of the box would be compliant installation based on what I see. ??
 

Smart $

Esteemed Member
Location
Ohio
What about 300.12?
I can't tell from the picture whether the ENT is continuous or not between terminations... but I do see the run as terminating at the trough... no different than an open bottom enclosure.

PS: Even if it was metallic raceway, bonding bushing on the end and bonded to the box and EGC's would be compliant in my book.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Although I don't see how that photo illustrates mechanical continuity between the raceway and the wireway since they're connected solely by air. Open bottom equipment falls under exception #2 in 300.12. I see no reason why this installation shouldn't meet the exception but according to the specific wording it doesn't. FWIW I've seen an entire apartment house wired this way.

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Smart $

Esteemed Member
Location
Ohio
Although I don't see how that photo illustrates mechanical continuity between the raceway and the wireway since they're connected solely by air. Open bottom equipment falls under exception #2 in 300.12. I see no reason why this installation shouldn't meet the exception but according to the specific wording it doesn't. FWIW I've seen an entire apartment house wired this way.
FWIW, 300.12 says they "shall be continuous between cabinets, boxes, fittings, or other enclosures or outlets." Note it does not say "...between and to..."

If a raceway protrudes into a box's space and has no breaks in it's run to the far-end termination, then the requirement is satisfied... technically. :happyyes:

It is only Exception No. 2 which implies there has to be mechanical continuity to the box unless open bottom equipment.
 

J.P.

Senior Member
Location
United States
Is there a code that states where more than 30 conductors are in the box, dividers must be installed? I was mentioned this but can't find a code reference.

A typical panel has more than 30 conductors.

In that trough. Is that 3/4 pvc? If so...you won't even need bushings afik. Isn't it 1" and larger pipe require bushings?

Edit: Never mind. I saw it is smurf pipe. Not sure why you couldn't run it like you have in the pic. People do it with pvc and switch gears that sit over the top of the pipes stubbed up through the floor. A simple slip in sleeve make the inspector happy in those situations.
 
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Transportation Guy

Senior Member
Location
Williamsburg,VA
Derating

Derating

So in this trough, because I have more than 30 current carrying conductors, these wires are only good for 35% of table 310.15? WOW! This trough is right above the panel. (less than 6') Please tell me I am missing an exception.
 

Smart $

Esteemed Member
Location
Ohio
So in this trough, because I have more than 30 current carrying conductors, these wires are only good for 35% of table 310.15? WOW! This trough is right above the panel. (less than 6') Please tell me I am missing an exception.
The derating kicks in at 31 in a cross section (and only for those in the cross section). Do you know what that means? In a "cross section" is key. I've seen "troughs" with hundreds of conductors yet no 31 in any cross section.
 

Transportation Guy

Senior Member
Location
Williamsburg,VA
I assume if I come in the top left corner and leave bottom right corner those conductors would cross the "cross section"? My plan in to come in from top and go straight out the bottom more or less.


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don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
So in this trough, because I have more than 30 current carrying conductors, these wires are only good for 35% of table 310.15? WOW! This trough is right above the panel. (less than 6') Please tell me I am missing an exception.
Take a look at the exception to 310.15(A)(2).
 

Smart $

Esteemed Member
Location
Ohio
I assume if I come in the top left corner and leave bottom right corner those conductors would cross the "cross section"? My plan in to come in from top and go straight out the bottom more or less.
Actually, I never really thought about it until now, but Code does not define wireway cross section. I've always thought of a wireway cross section as being any plane perpendicular to the long dimension... but Code does not really say that, so it could be any cross section at any angle.

Will the real cross section please stand up??? :p
 

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
Actually, I never really thought about it until now, but Code does not define wireway cross section. I've always thought of a wireway cross section as being any plane perpendicular to the long dimension... but Code does not really say that, so it could be any cross section at any angle.

Will the real cross section please stand up??? :p

Slim Shady!
 

JFletcher

Senior Member
Location
Williamsburg, VA
We are wiring a new hotel. The attached picture is what the AHJ in another state allowed. We didnt think out local would accept this because the ENT in the concrete doesnt terminate in the box. Thoughts?

It terminates *in* the box, not *to* the box. I suppose if he makes a deal of it, you could put a back plate on the box, uni-bit it, and put connectors on the ENT. I dont see a code issue here.
 
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