NEC 314.5 field installed screws

Jpflex

Jpflex

Electrician big leagues
Location
Victorville
Occupation
Electrician commercial and residential
I have always wondered if sharp wood screws to secure a box to support shuch as wooden studs (not part of box assembly or part of manufacture instructions) could be a code violation or issue with some inspectors.

I could not imagine blunt screws securing a box to a wooden stud?

Im aware that field installed holes must be approved but does this include the holes made at the side of a box and what if screws with sharp tip?
 
Jpflex said:
I have always wondered if sharp wood screws to secure a box to support shuch as wooden studs (not part of box assembly or part of manufacture instructions) could be a code violation or issue with some inspectors.

I could not imagine blunt screws securing a box to a wooden stud?

Im aware that field installed holes must be approved but does this include the holes made at the side of a box and what if screws with sharp tip?
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I would think that the head of the screw is what matters.

For example, panhead is better than hex-head.
 
LarryFine said:
I would think that the head of the screw is what matters.

For example, panhead is better than hex-head.
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I figured flat head screws would allow a flush screw with box but as NEC worded sharp wood crews may not be code compliant?
 
Jpflex said:
I have always wondered if sharp wood screws to secure a box to support shuch as wooden studs (not part of box assembly or part of manufacture instructions) could be a code violation or issue with some inspectors.

I could not imagine blunt screws securing a box to a wooden stud?

Im aware that field installed holes must be approved but does this include the holes made at the side of a box and what if screws with sharp tip?
Click to expand...
No idea what you are talking about. Plastic box secured through its side to a stud with screws?? What the heck would the tip (sharp or blunt) of the screws have to do with anything??

Why not just use a box made to mount to a stud to begin with?

-Hal
 
Jpflex said:
I figured flat head screws would allow a flush screw with box but as NEC worded sharp wood crews may not be code compliant?
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How does 314.5 prohibit sharp wood screws? , 314.5 addresses the part of the screw in wiring spaces if you secure a box to a surface with a Sheetrock screw or wood screw the pointed end will not be exposed to the wiring space
 
LarryFine said:
I would think that the head of the screw is what matters.

For example, panhead is better than hex-head.
Click to expand...

hbiss said:
No idea what you are talking about. Plastic box secured through its side to a stud with screws?? What the heck would the tip (sharp or blunt) of the screws have to do with anything??

Why not just use a box made to mount to a stud to begin with?

-Hal
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Indeed. The first provision of the code is that the screw should be blunt.

Second, an example which i personally encountered was a boss who ordeeed double drywall boards (probably for fire rating) to cover stud walls.

Installing single and double gang plastic boxes supplied with nails by manufacture (sharp) could no longer be installed flush with drywall (not tab type)

Wood backing boad behind box was installed and metal screws at inside of box to studs
 
Jaybone812 said:
How does 314.5 prohibit sharp wood screws? , 314.5 addresses the part of the screw in wiring spaces if you secure a box to a surface with a Sheetrock screw or wood screw the pointed end will not be exposed to the wiring space
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Perhaps may or not be NECs intent but as it is stated in 314.5:

Screws or other fasteners installed in the field that ENTER WIRING SPACES shall be as provided by or spcified by the manufactute or shall comply with the following

(1) screws shall be machine type with BLUNT ENDS.
 
Jpflex said:
Screws or other fasteners installed in the field that ENTER WIRING SPACES shall be as provided by or spcified by the manufactute or shall comply with the following
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That refers to screw ends or threads in the box, not screws whose heads only are in the box.
 
Jpflex said:
Perhaps may or not be NECs intent but as it is stated in 314.5:

Screws or other fasteners installed in the field that ENTER WIRING SPACES shall be as provided by or spcified by the manufactute or shall comply with the following

(1) screws shall be machine type with BLUNT ENDS.
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That enter wiring spaces , they are taking about screws you use to secure covers , like a 4” metal 1900 box blank cover , the 8-32’s will enter the wiring space so they have to be blunt ends , in no way does the language adress what you are saying, how can you consider the end of a screw you use to rigidly secure a box to a surface as entering the wiring space ?? It may enter for 1/2 a second when you secure the box but that’s not what the language or intent is adressing and the code making panels expect us in the field to actually have common sense and common sense says this rule has nothing to do with the point of the screw used to secure the box to a surface . If it did how would it be code compliant to mount regular 4” 1900 boxes to a surface unless they were bracketed ?? Think about it
 
Jpflex said:
(1) screws shall be machine type with BLUNT ENDS.
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One example of what this means is that you cannot use a Sheetrock screw to screw in a device with a metal box that has a mud ring. Same would apply to the screws used to hold on a blank cover on a metal box.
 
At rimes I feel the NEC gets too "pickey" but this is one rule I agree with. All too often in inspecting I have found conductors, especially larger ones, with insulation damage from sharp pointed "non-factory" cover screws.
 
Jaybone812 said:
Exactly thank you sir , if his thinking were true how could we mount any boxes in the field that have internal holes with sharp ended screws ??
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I Was not thinking this was NECs intent but merely going based on the NECs wording
 
jim dungar said:
What are the exact words?

Doesn't Arlington make a Listed adjustable box that mounts with pointed wood screws?
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Plastic gang boxes come with manufacture supplied sharp metal wood nails. However, these are not inside the box nor penetrate inside the box. The nails are supported outside the boxes and "do not enter wiring space."
 
jim dungar said:
What are the exact words?

Doesn't Arlington make a Listed adjustable box that mounts with pointed wood screws?
Click to expand...
Screws or other fasteners installed in the field that enter wiring spaces shall be as provided by or specified by the manufacturer or shall comply with the following as applicable:
  1. Screws shall be machine type with blunt ends.
  2. Other fasteners shall have blunt ends.
  3. Screws attaching a cover shall extend no more than 10 mm (3/8 in.).
  4. Screws or other fasteners, other than in (3), penetrating a cover shall extend no more than 8 mm (5/16 in.).
  5. Screws or other fasteners penetrating a wall of a box exceeding 1650 cm3 (100 in.3) shall extend no more than 6 mm (1/4 in.), or more than 11 mm (7/16 in.) if located within 10 mm (3/8in.) of an adjacent box wall.
  6. Screws or other fasteners penetrating the wall of a box not exceeding 1650 cm3(100 in.3) and not covered in 314.23(B)(1) shall be made flush with the box interior.
  7. Screws or other fasteners penetrating the wall of a conduit body shall be made flush with the conduit bodyinterior.
Exception to (3) through (6): A screw shall be permitted to be longer if the end of the screw is protected with an approvedmeans.



These is the exact language of 314.5 common says tells me they are not referring to the end of the screw used to rigidly secure the box to a surface 🤷‍♂️
 
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