Drywall screws to mount electrical panels

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jwelectric said:
Many years ago I even used sheet rock screws to install a radiator in an old Nash Rambler.
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I hope you used the fine-thread type made for metal studs. :)

. I traded that old Nash for a Studebaker that had the exhaust tied up with coat hangers..
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Not Mineralacs on all-thread? Better yet, Uni-strut and straps! :rolleyes:
 
dnem said:
The thread is about weight and application (as in, an application that subjects the screw to blunt shock sheer forces) restrictions.
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All right, how about this snippet from this source:
  1. Type ?S? Fine thread drywall screw withdrawal load = 39.61 lbs (safety factor of 5)
  2. Type ?S? Fine thread drywall lateral resistance load = 60.22 lbs (safety factor of 3.2)
  3. Type ?W? coarse thread drywall screw withdrawal load= 38.42 lbs (safety factor of 5)
  4. Type ?W? coarse thread drywall lateral resistance load = 50.56 lbs (safety factor of 4.46)
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If I am looking at what I think I'm looking at, I would need to install over 90 pounds worth of panelboard, breakers and conductors to overwhelm three drywall screws. Is this correct?
 
the only problem I have with sheetrock screws, is the guys who throw away the screws that come with a listed fan box and use sheetrock screws.

how could this subject possibly have 5 pages, i guess its better than SE cable underground
 
Well, to be fair, at least two of the pages were dedicated to berating David for bringing it up. :D

And now, for my jab at you, you still managed to squeeze in a SE cable reference in your post! I'm starting to think someone stole your code book, but ripped 338 out and left it sitting on the seat of your truck! :D :D

(To be clear, I'm just having fun. :) )
 
georgestolz said:
A


If I am looking at what I think I'm looking at, I would need to install over 90 pounds worth of panelboard, breakers and conductors to overwhelm three drywall screws. Is this correct?
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Of course not, you haven't introduced the pulling tension from conduit runs.
 
George, well, it depends...

Those numbers cite ASTM D1761, "Standard Test Methods for Mechanical Fasteners in Wood." The withdrawal number is the force required to pull the screw out along its axis, and that is probably not the number of concern. The lateral resistance is indeed similar to what you would see from the weight of the panelboard on a wall. But the lateral resistance is tested with a 25/32" (.781") thick piece of wood being screwed to a 2" thick piece of wood, and a 2 1/2" long fastener screws into both pieces of wood. Putting up a panelboard, the threads of the fastener would (presumably?) not see significant engagement with the panelboard, and I think most panelboards are less than 25/32" thick, so there may be more force concentrated on the head of the screw, which may be weaker(?). Furthermore the gypsum board between the panelboard and the stud is not as strong as the wood that this test is done with.

On the plus side, there are those safety factors. ASTM D1761 is silent on them, so one imagines they were chosen somewhat arbitrarily by the manufacturer who wrote the specifications in question.

Lastly, of course, you have to watch out for uneven loading of the screws.

I'm a bit unclear whether this thread is asking about screws being screwed into studs or into drywall, and whether the studs are wood or metal.

---

I'm sure you can tell I was lurking in the wings waiting for my one-year anniversary for a thread where I had something to contribute. I just wish it wasn't this one :D.

Hey Scott, don't confuse us Cantabrigians with the people actually run the city. We just live here!
 
Perhaps it would be more profitable to have a show of hands of all the people that think mounting panelboards with sheetrock screws is a really good idea?

I've got to say that I carry a can of sheetrock screws, but only for a very few select things. One... for sheetrock. Two, for mounting Wiremold 500 and 700 mounting clips, since the assembly doesn't tolerate much of a head on the screw. That's about it. For mounting everything else, I use pan head or hex-washer-head sheet metal screws.
 
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I like pan head #10's for mounting panels in wood. They do a good job.

I use drywall screws for mounting one-holes on the surface of drywall for 1/2 and 3/4 EMT, and mounting 4-squares. They seem to hold well, if not stripped out. If they strip out the steel stud, wash, rinse, repeat. :)
 
I pretty much use the #10s for everything. If your in wood they are overkill for a lot of small items but they are plated and will not rust.

A plain old #10 will spin itself into light gauge steel studs and holds OK, heavy gauge studs I use #10 or larger Teks.

If you have light gauge studs and want a better than average hold drill a 1/4 hole through the drywall and stud then run a metal "ZIP IT" anchor into that hole. Now you can run a #10 into the zip it.

If I have real heavy equipment to mount on light weight studs I use 1/4" toggles right through the stud itself.
 
roger said:
Here is a picture of the smart box with the sheet rock screws originally posted by Mdshunk in another thread.
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I will repeat my question: are all bugle-head screws drywall screws?

(Picture eliminated in the interest of saving space)
 
LarryFine said:
I will repeat my question: are all bugle-head screws drywall screws?
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No, personally I stop calling them dry wall screws once they are larger than #6s

I keep various length and size treated 'deck screws' in the truck and they are bugle head. They work well for fastening lumber when I have to.
 
mdshunk said:
Perhaps it would be more profitable to have a show of hands of all the people that think mounting panelboards with sheetrock screws is a really good idea?
.
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Probably every panel I have installed has been with 4 drywall screw with 1" washers. They are all still hanging as far as I know.

I think it is a great idea.
 
LarryFine said:
I will repeat my question: are all bugle-head screws drywall screws?
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Sorry, I didn't see your first question, must of skipped over it, but the answer is, Heck no, there are also Deck Screws, Picture hanging screws, Electrical Equipment Mounting screws, Miscelaneous screws, Smart Box screws, or any term you personally feel like attaching to a bugle-head screw, even Ground screw for the time being. :rolleyes:

Roger
 
I do mostly residential with obviously wood. I almost always use the coated deck screws/washers to mount my panel to the two studs on eiather side of the panel. If I am fastening to metal I use number 10 apparently the same as everyone else. I do a fair amount of service upgrades on the outside and the houses are rock and then I use tapcons. I have used just plain old everyday sheetrock screws but never to replace listed equipment that came with the assembly.
 
LarryFine said:
I will repeat my question: are all bugle-head screws drywall screws?

(Picture eliminated in the interest of saving space)
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Actually the head isn't the critical determining factor, altho the head is what signals the presence of a "drywall/sheet rock screw". . The critical determining factor in the past was the chemical treatment of the screw that kept it from decomposing in the drywall. . That treatment made the screw brittle but I'm told the chemical process has been changed [in response to power tool screw head twist offs].
 
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