ECN Forum Forums Code Related Discussion NEC & other Code issues Lets Talk About Screws Some More

...and I've not seen an electrician yet who has a set of taps as well as number drills on his belt...

Look no further. I always carry a Klein triple tap (actually six different taps). I usually run the proper size through all tapped holes to clean them up. Beats cranking a screw in with a screwdriver that doesn't want to go because the hole is tapped undersize or damaged.

Keep the proper size tap drill bit in your drill case and you are all set.

I do agree with you otherwise.

-Hal

I am still waiting for someone to point us to a UL listed grounding screw.

Or a UL category for such a thing.

Bob
I hope you have a lot of patience

Pierre

LOL Sometimes yes and other times not so much.

For this the wait may be long.

Bob

(throws a little gas on the 'screw' fire)
The IDEAL catalog I have from 2000 on page A-11 shows a UL and CSA stamping for the whole grouping of grounding connectors and accessories, which includes the screws. BUT... the online catalog page show specific bullets of UL Listed on all but the couple of bare screws. I'm going to drop a note to IDEAL rep and see what he comes up with.

Mean Gene, that fix doesn't work. You need to use a listed box, and I've never heard of listing agency with the mark "JU" .

A second for the Kleing 6-in-1 tap tool.

[mutter]damn Chinese 'standard threads' [/mutter]

Yeah,me too Doug.

UL under listing (KDER)Addresses Grounding and Bonding Equipment .

The catagorey covers bonding devices, ground clamps, and bonding bushings and locknuts, ground rods, armored grounding wire, protector grounding wire, grounding wedges, GROUND CLIPS FOR SECURING THE GROUND WIRE TO AN OUTLET BOX, watermeter shunts, and similar equipment.

UL nor other NRTL's list screws per say for the attachment of equipment grounding conductors to enclosures.

The following 2005 comment seems to indicate that CMP 5 accepts screws (other than coarse Thread SMS) all be it unlisted for this purpose


on Comment 5-40 only be reported as “Hold” consistent with Section
4-4.6.2.2 of the NFPA Regulations Governing Committee Projects. The
comment adds new material that has not had adequate public review. The
action on Proposal 5-57 stands as shown in the Report on Proposals.
Submitter: Frederic P. Hartwell, Hartwell Electrical Services, Inc.
Comment on Proposal No: 5-57
Recommendation: Accept the proposal in principle. Revise the last sentence
to read as follows:
“Where screws are used to make field connections of grounding conductors
or grounding terminals to enclosures, machine screws or thread-forming screws
with machine threads shall be used.”
Substantiation: The disallowance of sheet metal screws for this purpose is
appropriate, but the wording has raised three questions: what about metal-tometal
connections in listed enclosures, where the continuity has been evaluated
by the testing laboratory (presumably OK), and on field connections, what
about other screws, such as wood screws that are even less suitable than sheetmetal
screws? What about “teck” thread forming screws that result in machine
threads, but that are often referred to as a type of sheet metal screw? This
comment answers those questions. The real technical issue addressed in this
requirement is the poor mechanical advantage offered by a conventional sheet
metal screw with its very coarse threads. The submitter is aware that this comment
may need to be held in accordance with 4-4.6.2.2(a) of the Regulations,
but wanted to bring the issues to the attention of CMP 5.
Panel Meeting Action: Accept
Number Eligible to Vote: 16
Ballot Results: Affirmative:

"
Keep the proper size tap drill bit in your drill case and you are all set."

I use the Klien tapping tool also. It's great for fixing the bottom hole in a metal box mounted in a masonary wall that usually has the screw rusted in. I use a #26 drill for the #10 tap, but I confess I don't know what the corrosponding drill sizes are for the #6 & the #8 taps, if anyone could help me out here.