Can I use sheet metal screws to put a panel cover on?

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Can I use sheet metal screws to put a panel cover on?

  • Only the manufactures supplied hardware?

    Votes: 78 40.8%
  • Any short machine screw that fits?

    Votes: 88 46.1%
  • Sheet-metal screws?

    Votes: 9 4.7%
  • Tek-Screws?

    Votes: 5 2.6%
  • Nail it on with Ramset?

    Votes: 9 4.7%
  • Why would I put the cover on?

    Votes: 14 7.3%

  • Total voters
    191
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Article 90.1

Senior Member
I've also sometimes ripped out cover clamps and drilled/tapped for screws. I have nothing good to say about clamps. Nothing but trouble and I've seen them pinch wires more than once.
Amen to that! Like the time I shut down a Coca Cola office when I got a conductor caught behind one of those STUPID clamps. I do the same thing, rip them out, then use 1/4"x20 bolts, I usually add one to the top of the panel and screw it in from the back. This way you can hang the cover on the bolt and make up the rest.
 

jeremysterling

Senior Member
Location
Austin, TX
Amen to that! Like the time I shut down a Coca Cola office when I got a conductor caught behind one of those STUPID clamps. I do the same thing, rip them out, then use 1/4"x20 bolts, I usually add one to the top of the panel and screw it in from the back. This way you can hang the cover on the bolt and make up the rest.

Thanks for fixing that! I like the top stud sticking out. Nice improvement. Those quarter turn clamp covers didn't usually have the bottom rest ledge, so your "hanger stud" works great. I've seen a panel modified in this manner once or twice.

I'm agreeable to most fasteners being used as long as they are consistent. Sometimes you need two different nut-drivers plus two different screwdrivers to take off the cover because of the mismatched hardware.

I'll use fine thread #10 Teks all the way around (the ones on the left in iwires post).

Like someone already posted, I'll try groundscrews for the deadfront, unless they're stripped, then they get Tek screws, too.
 

Cavie

Senior Member
Location
SW Florida
That is not a code section. :)

You can use what makes you happy, my question is what does the NEC prohibit, if anything.


Nope, you will not find a code section to cover this cover issue but the panel was listed with machine screws wasen't it. You will notice some panels come with thoses strange looking sheet metal looking screws ( CH I think). Then I'm sure you'll get away with the sheetmetal screws on those but then they have those double loops to capture the threads. I love it when some yahoo strips out the machine threads using sheet metal screws and you find a bigger sheet metal screw in it's place. I never giged anybody for it on a old install but new panels got the proper screws what ever type they happened to be. Don't bother to ask me why, I don't have an answer. I have seen real machanics tap out the old stuff and install new machine screws but that was very rare.
 

iwire

Moderator
Staff member
Location
Massachusetts
Nope, you will not find a code section to cover this cover issue but the panel was listed with machine screws wasen't it.

Sure the panel was listed, do we know if the scews are part of the listing?

For instance, if I buy a home cheapo light fixture that comes with the wire nuts that are all plastic do I have to use them or can I use 'real' wirenuts? Do I have to use the screws that came with it that seem to be size '7' when the box needs 8-32s?



I never giged anybody for it on a old install but new panels got the proper screws what ever type they happened to be. Don't bother to ask me why, I don't have an answer.

So you would fail something without knowing the reason why. Well I appreciate your honesty. :)

I guess that would fall under 'The not in my town' rule. :grin:
 

electricmanscott

Senior Member
Location
Boston, MA
Amen to that! Like the time I shut down a Coca Cola office when I got a conductor caught behind one of those STUPID clamps. I do the same thing, rip them out, then use 1/4"x20 bolts, I usually add one to the top of the panel and screw it in from the back. This way you can hang the cover on the bolt and make up the rest.

You do realize half the guys reading this just flipped out because you modified a listed product. :roll:
 

iwire

Moderator
Staff member
Location
Massachusetts
OK I used some of these screws to close a panel up the other night.

301Tek-1.jpg


Was I wrong to do so?
 

hardworkingstiff

Senior Member
Location
Wilmington, NC
OK I used some of these screws to close a panel up the other night.

301Tek-1.jpg


Was I wrong to do so?

IMO (not that it counts, but you asked) it was unwise but not as bad as a sheet metal screw.

I think a blunt end machine screw would be 2nd best to the screws that come with the panel. I am surprised that you do this with all of the technical views you have posted, I guess that means you see nothing wrong with it and no one can prove it is wrong. (My wife was looking over my shoulder and said this seems derrogatory. I do not mean it that way).

Edit: I've done the same thing before myself (using a TEK screw).
 

hillbilly1

Senior Member
Location
Atlanta,Ga
Occupation
Field coordinator/ technical support
I have turned down many jobs for sheet metal screws. There are machine threads in the panel. They get machine thead screws installed.

Many manufactures of single phase loadcenters do not thread the holes, they use screws that create the threads once they are installed. Not saying sheet metal screws are correct or not, but the factory holes are not always threaded.
 

iwire

Moderator
Staff member
Location
Massachusetts
must be a huge panel you closed with these screws;)......... on my screen they have 1" wide threads and they're almost 6" long from the washer to the tip.:cool:


:grin:


How about this, now you can compare it's size against a Fluke T5 tester.

3012Tek.jpg
 

jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
Re: Cutler Hammer screws. Those look like sheet metal screws, strange thread. I don't like them much. If I have trouble with them, I drill and tap for 10-32 or 1/4 x 20 if hole is too large.

I'm surprised how many like tek screws for covers. I hate them, as they will usually mess up whatever thread is there. I think 10-32 should be the norm for smaller covers, 1/4 x 20 for larger ones. Easy to replace if lost, screws should be relatively trouble free.

It would be a simpler world if all covers were either shoe box or hinged and all cover screws 10-32 or 1/4 x 20.
 
Last edited:

jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
Who designied those &%$& SQ D toggle bolt screws?
Are you talking about the long clamps used for covers on an oddball panel Sq D made years ago? With sharp pointed clamps that go nearly all the way to the sides of the panel can? One of the few truly stupid things Sq D ever did was make that panel. I can't remember the model or common name for it. I only saw one of them. Also had a weird breaker with some kind of flexible strips to terminate. Someone designed all that on a Monday following a 2 week drunk or drug binge.
 

SEO

Senior Member
Location
Michigan
Are you talking about the long clamps used for covers on an oddball panel Sq D made years ago? With sharp pointed clamps that go nearly all the way to the sides of the panel can? One of the few truly stupid things Sq D ever did was make that panel. I can't remember the model or common name for it. I only saw one of them. Also had a weird breaker with some kind of flexible strips to terminate. Someone designed all that on a Monday following a 2 week drunk or drug binge.

Installing that type of cover you have to be very careful not to have a conductor under the clamp. Almost everone who has had experience with that kind of cover has had or seen that problem before.
 

marti smith

Senior Member
iwire,

I think it is wrong to use those screws. Yes, they'll do in a pinch, but I'm still going with 250.8(5), (6), and(7) because if we look at 408.2, Art 314 is included. 314.40 (B) goes over thickness of the metal: and two of the threads of the shown screws are greater in depth than that of the thickness of the metal, and so ideally(sp?) there is not 2 threads engaged. They work, I've used them before, but as to the code, no-go IMO.

A very good question. Some good debating as well. :roll:
 
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