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#172204 - 12/15/07 11:22 PM Do they make a "TEK" style ground screw  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,124
Estero,Fl,usa
I was wondering if they have one with a drill head and the regular self tapping swageform 10-32 threads. Seems like a great time saver when you are grounding a cabinet or other enclosure without pre-tapped holes.


Greg Fretwell

Work Gear for Electricians and the Trades

#172207 - 12/16/07 12:28 AM Re: Do they make a "TEK" style ground screw [Re: gfretwell]  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
Well, this is one issue that simply is never going to go away.

Most 'teks' screws have threads that, IMO, are close enough to 'machine screw threads' to count. If you're also talking 'silver bullets,' then they even have something that approaches a binding head.

I am still more than a little PO'd about the way horses were changed in mid-stream, a la AFCI's. To justify this 'no sheet metal screw' nonsense, a certain 'code authority' circulated all manner of pictures showing obviously loose, inappropriate, ordinary screws going into oversize holes.
Once the code came out, this same person went on a crusade against the lowly 'teks' screw, even when properly installed. Thus began this debate.

Greg ... engineering analysis aside ... I'd be happy when the fastener is tight, and used as intended. As long as the metal of the wire is held tight against the metal of the box, I'm not going to lose any sleep.


#172211 - 12/16/07 03:40 AM Re: Do they make a "TEK" style ground screw [Re: renosteinke]  
ausador  Offline
Member
Joined: Mar 2007
Posts: 49
Central Florida
Greg...
A trick I figured out from desperation once....

Buy Sq-D ground bar kits, they are available in 3-hole thru 23-hole. They also include a unique sort of triangular cross sectional tapered self thread cutting screw(s).

Buy 3/4" x #8 self drilling screws (self tappers), these will be useful later as I will explain.

Now you have a ground bar and self drilling screws but one is not allowed to be used with the other right?. frown

However in this case it is exactly what you need, espicially if you have a box/panelboard/gutter/whatever mounted to concrete. There is no way to drill and then tap a hole in boxes mounted to concrete?....there is.

If you position the groundbar where you want it and then use the #8x3/4" self tapper to drill the pilot hole the Sq-D provided screw(s) will cut thier own threads and suck up as tight as it is possible, you'll strip out the screw head before the the screw strips in the can hole you have made.

Anyway the basic trick is to use a #8x3/4" self driller as a pilot hole for the Sq-d groundbar screws,it works and it works great. You dont need a tap, you don't need to pre-drill a specific size hole knowing your bit will run against concrete and be ruined once you punch through.....

If you hold the groundbar in place and use it as a stop then only the cutting head of a 3/4" self-driller will go through, no threads will catch.

I have used this over and over again to ground existing pull boxes, gutters, and older panel cans, it WORKS!!

Hope this helps.... Greg



#172252 - 12/16/07 11:11 PM Re: Do they make a "TEK" style ground screw [Re: ausador]  
JBD  Offline
Member
Joined: Jul 2001
Posts: 599
WI, USA
Originally Posted by ausador
Now you have a ground bar and self drilling screws but one is not allowed to be used with the other right?.


The NEC prohibits "sheet metal" screws. Self-tapping "machine" screws are allowed. Self-drilling non-sheet metal screws are not addressed. In 2008 the screw requirements will finally consider both thread pitch and material thickness.


#172260 - 12/17/07 01:44 AM Re: Do they make a "TEK" style ground screw [Re: JBD]  
EV607797  Offline
Member
Joined: Oct 2006
Posts: 745
Fredericksburg, VA, USA
Drywall screws have also been a continuing source for problems. I can't tell you how many times that I've encountered ground bars that are attached with them, and to make it worse, with coarse-thread ones. Maybe a chance that one thread might catch.


---Ed---

"But the guy at Home Depot said it would work."


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