You better not use drywall screws. I have not seen any green ones to date.

Try this put in drill & tap.that the way to do it.

While i am aware that it does not prohibit drywall screws or wood screws, a electrician would understand that drywall screws and wood screws are not to be used. A electrician would take the time to use a proper machine type screw with a nut should he not have the supplied manufacturs screw.

This concerns the comment about using a wood screw or a drywall screw for equipment ground.

I have never seen a listing for either, and since neither is a "listed fitting", they are not allowed in our jurisdiction.

If you cannot use sheet metal I am sure inspectors would have a problem with wood screws. Let use nails, carpet tacks, or liquid solder for that matter.

I believe the \"intent\" is for machined threads, not coarse threads as are wood, sheet metal, drywall screws, etc. Nor do I believe these type items are \"listed\" for the use you are wanting to attach the grounds.

I would also add a 1/4 20 machine bolt is a violation.

min threads/inch for grounding if I remember correctly 28

Mike, As you are aware, for the 2008 Code cycle, CMP 5 has extensively revised the text to 250.8, and exactly defined the types of screws that may be used. Perhaps it is time to do away with your comment about drywall screws and wood screws? This seems to steer some readers into actually believing that these screws would be OK to use.

I don't see, for the life of me, what the difference between a "sheet metal screw" and a regular drywall screw would have on the integrety of a bonding system. I personally don't like either because of the metal stripping out. I do like a standard threaded 10-32 in a metal of adequate thickness much better, tho.

Keep going Mike, I know of no better way to remind and educate than a little at a time as you are doing. Small bites of the large elephant.

Thank you for doing this great job.

David W. Smith Ph.D

what is the reason, the sheet metal or self taping screw are not to be used. As we all know the screws hold building steel togeather, and when we bond to the structureal steel the building is considered bonded togeather.

Hello, I have a question about the ground wires in the time clock. It is my understanding that the clock itself needs to be grounded. In the picture being that it does not bolt in and just clips in. So what i'm asking doesn't the two grounds need to be made together, not separate like they are?

The rule is to prohibit 'self threading' screws, not the specific type of 'self threading' "sheet metal" screw . You cannot guarantee the integrity of threads cut by these screws in a sheet metal box, therefore the screw and nut method, or the formed thread in sheet metal method is preferred (or the rule).