I got a 125Amp panel (Siemens) for installation, and found that the cover screws included did not fit. I later found that my sheet metal screws, fit perfectly. Are there any NEC guidelines against this?actual screw screwed in sheet screws.

  • is the panel correctly assembled?
    – jsotola
    Apr 4, 2020 at 1:00
  • Yeah, the problem I had was that the panel cover was really loose when I screwed it in. (*the original screws) Apr 4, 2020 at 1:04

1 Answer 1


That self tapping screw is a code violation and I know several inspectors that will fail a home owner and an electrician for not using load center cover screws.

The load center screws have a larger head and almost always have a #2 square / slotted head , I got hammered many years ago and even stock several different brands as they are different.

Many of these screws are self forming NOT self tapping. Code specified self forming 2 threads in contact, yes self forming are tough to put in the first time but believe me that is a red flag for inspectors in my area.

I believe 1 brand has corse threads but it is a large head with a slotted / #2 square drive and is ok because it is according to the mfg directions. Self tappers do not.

  • 1
    The OP probably ruined the hole with the self tapping screws.
    – JACK
    Apr 4, 2020 at 12:28
  • What are they citing for the failures? 250.8(A) (with the screw as a system or supply-side bonding jumper between cabinet and front)? Or is this more of a listing/instructions issue? Apr 4, 2020 at 14:16
  • 110.2 the mfg listed equipment has load center cover screws not self tappers. As I said some mfg’s do have corse screws but they still have the oversized heads. 250.8 is for grounding and bonding it specifies 2 threads or secured with a nut. 314.25 covers and canopies where nonmetallic or metal covers and plates , machine screw matching cover size , I think there is another reference to #6, #8 & #10 screws 32 pitch but I may be combining a cover plate grounding requirement. So there are several references with the mfg listed assembly being first.
    – Ed Beal
    Apr 4, 2020 at 19:31
  • @EdBeal -- yeah, makes sense that it'd get written up as a 110.2, given that a too long or too pointy screw can mess up wire insulation Apr 7, 2020 at 1:08

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