clearance for 4 square J box?

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J.P.

J.P.

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What is ( and where is ) the clearance required in front of a jbox? I thought I had seen a number on this before but now I can't find it. How much room in front of a 4 square jbox is required?

I ask because the mechanical crew just started running their duct very close to the wall and just about touching out wall mounted jboxes.
 
So there would not be enough space to remove the cover, let alone work on the wires in the box? To my mind that would make the box inaccessible in principle whether or not it fits the NEC definition.
 
It's 24"x16" square duct hanging from straps. It has about 2" of swing to it.

But yeah, it would pretty much suck to work on those boxes.

I'm right on ( and down to receps inside ) a block wall and of course their prints show the ducting right on the wall as well......

Edited for bad measuring:)
 
314.29 applies, but it is a subjective rule without out a specific space required. It would be my opinion that the box in question is in violation of 314.29.
 
Not a good install, likely not compliant. But, that's what stubby screw drivers are made for. The electrician will likely have to have the power off to pull wires out. But once you get them out you can check for good connections. Squeeze them back in the box, screw the cover on and your done. Just don't add any thing where you'll need a box extension.
 
don_resqcapt19 said:
314.29 applies, but it is a subjective rule without out a specific space required. It would be my opinion that the box in question is in violation of 314.29.
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I think a couple of things are in order. First is to review the definition of accessible.

Accessible (as applied to wiring methods). Capable of
being removed or exposed without damaging the building
structure or finish or not permanently closed in by the structure
or finish of the building.
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I think it is quite possible to move the ductwork without damaging anything. It might be inconvenient, but possible.

314.29 Boxes, Conduit Bodies, and Handhole Enclosures
to Be Accessible. Boxes, conduit bodies, and handhole
enclosures shall be installed so that the wiring contained
in them can be rendered accessible without removing
any part of the building or structure ...
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Is the ductwork part of the building or structure? If so, then maybe there is a problem. However, if one could use an offset screwdriver to get the cover off by moving the ductwork a few inches, I don't see how it is in violation of this provision.

JMHO.
 
It is a subjective rule, and I would likely give it a red tag if there was less than 15" of space between the duct work and the box cover.
 
petersonra said:
where does the standard of 15" come from? that is certainly not found in the code.
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It will depend how the AHJ interprets the code. I don't think it is a standard, but if I was the inspector I would red tag the installation under 90.4, 110.26 and 314.29. But now the question is who moves their install? The HVAC or the EC?

I guess it would be the HVAC guy because he installed last.
 
edward said:
It will depend how the AHJ interprets the code. I don't think it is a standard, but if I was the inspector I would red tag the installation under 90.4, 110.26 and 314.29. But now the question is who moves their install? The HVAC or the EC?

I guess it would be the HVAC guy because he installed last.
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Don't forget the code: Because I said so.

"110.2 Approval. The conductors and equipment required or permitted by this Code shall be acceptable only if approved."

"Approved. Acceptable to the authority having jurisdiction."
 
mshow1323 said:
Don't forget the code: Because I said so.

"110.2 Approval. The conductors and equipment required or permitted by this Code shall be acceptable only if approved."

"Approved. Acceptable to the authority having jurisdiction."
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IMO, 110.2 applies to wiring and equipment NOT how they are installed.
 
I would think (bad move, huh?) that if conductors are required to be able to extend 3" past the front edge of a box.....they should be able to at least be able to extend 3" past the front edge of a box unobstructed. That would also allow for removal of a JB cover with a stubby screwdriver.
 
What is purpose of removing the cover if you can not safely work on the conductors.
If removing the cover is all we need then why not have the duct an inch away from the jbox.
Even though Don can not cite a section for the 15", I think it is a good common sense.
 
We try not to but due to variations of construction. We install boxes all the time with less then 15" clearance. I could pull wire, push fish tapes and make joints within 6 inches or less, easy.
 
On a site with construction drawings, I always refer to the HVAC plans to set up my runs by! Sometimes you can pick up other invaluable (IMO) information.

It's usually a case that I will run with-in 4" in respects to usually the X & Y of the bottom of a trunk run.
While it might be a case that I have to run up and over to get there, this clears all branch and insulation of the trunk, and usually leaves 2" free between systems.
This can also help place boxes for inline fan coils, FA interfacing and thermostats placements.
 
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don_resqcapt19 said:
As I said it is a subject issue, that number is just my number and what I would enforce.
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edward said:
What is purpose of removing the cover if you can not safely work on the conductors.
If removing the cover is all we need then why not have the duct an inch away from the jbox.
Even though Don can not cite a section for the 15", I think it is a good common sense.
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Just where should one set such a distance?? I have seen boxes with more then 15" free space directly in front of them, but you may still need to be a really small person just to get to this 15 inches of clearance making a box in another location with only 4 inches in front of it more accessible to most people.

If you want to use 15", that means a box mounted on the side of 16 inch centered floor joists (that are otherwise open/exposed) is also in violation, and I've seen and installed many in that kind of instance with no troubles accessing them.
 
iwire said:
And I think that would be unprofessional of an inspector. That is clearly making a rule up.
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That happens with the enforcement of every subjective rule in the code book. How can any subjective rule be enforced without "making up a rule"?
 
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