Ground Screws

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binney

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Does anyone make a self drilling ground screw? I've seen self tapping ground screws, but never a self drilling ground screw. I'm not talking a #10 self tapper, but something with a self drilling tip and 10-32 threads.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Would you settle for the next best thing?
drilltap.jpg
 

binney

Inactive, Email Never Verified
I have had several sets of these, but a self drilling screw would be awesome, something I can keep in the belt and not cost $30 to replace. If a ground clip can be legal there has to be a way of making a self drilling groung screw.
 

tallguy

Senior Member
binney said:
Does anyone make a self drilling ground screw? I've seen self tapping ground screws, but never a self drilling ground screw. I'm not talking a #10 self tapper, but something with a self drilling tip and 10-32 threads.

Poked around a bit and this was what I found. Of course these are not advertised as ground screws, but it shouldn't matter from an NEC perspective. It's going to cost you ~$.20 a rip to use one (#10 x 1/2") -- cheap really considering the labor saved.

Here's another one.
 

tom baker

First Chief Moderator
Staff member
Those screws won't be allowed in the 2008 NEC, it will call for a machine screw with at least two threads in contact with the enclosure. (this is a change to 250.8)
I prefer the greenlee tap it, they are great.
 

tallguy

Senior Member
tom baker said:
Those screws won't be allowed in the 2008 NEC, it will call for a machine screw with at least two threads in contact with the enclosure. (this is a change to 250.8)
I prefer the greenlee tap it, they are great.

So if a 10-32 self-drilling screw were available we'd be OK?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Minuteman said:
Zip in a #8 drill tip screw with a 5/16" head, back it out, zip in a self tapping 10-32 greenie screw. Done!


A self tapping #10 greenie screw will go into a #8 hole?
 

TOOL_5150

Senior Member
Location
bay area, ca
LarryFine said:
Would you settle for the next best thing?
drilltap.jpg


I bought a set of these, and they are great. But does anyone have any good ideas for tapping holes when the panelboard is allready installed, and you dont have much more than 1/4" - 1/2" of clearance behind the panel?
 
I am stretching here...from somewhere in my memory...maybe someone else here can help.

Tapping a panel enclosure for the grounding screw is not permitted, one would need a bolt and nut or other effective means.

When a manufacturer taps a box, they actually put a "dimple" in the box creating a little more "meat" at the location so there is enough threading for the screw to catch. When we drill and tap there will not be enough threads.
Of course if I am wrong, it will be established before the end of the day.
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
TOOL_5150 said:
I bought a set of these, and they are great. But does anyone have any good ideas for tapping holes when the panelboard is allready installed, and you dont have much more than 1/4" - 1/2" of clearance behind the panel?

Use Minuteman's method. You may have to shorten up a soft ground screw for the final installation. Scrape the paint and go home. Not sure about Pierre's concern. Never have been called on it.
 

Minuteman

Senior Member
infinity said:
A self tapping #10 greenie screw will go into a #8 hole?

If you use a DeWalt 18volt impact driver like this, it will! :cool:


DW056K-2_1.jpg


If you use a #10 screw to make the pilot hole, the greenie may be too loose. Self tapping greenies are tapered at the end and have cutting edges to cut the threads.

FWIW, There are two types of self tapping greenies. Both have the taper, but one has a large notch and the other has several lengthwise grooves. I prefer the ones with the notch.


.
 

electricman2

Senior Member
Location
North Carolina
Occupation
Retired Electrical Contractor
Pierre C Belarge said:
I am stretching here...from somewhere in my memory...maybe someone else here can help.

Tapping a panel enclosure for the grounding screw is not permitted, one would need a bolt and nut or other effective means.

When a manufacturer taps a box, they actually put a "dimple" in the box creating a little more "meat" at the location so there is enough threading for the screw to catch. When we drill and tap there will not be enough threads.
Of course if I am wrong, it will be established before the end of the day.
This is true. Simply drilling a regular panel enclosure using a 10-32 tap will not provide enough threads to secure a ground or anything else.
 

TOOL_5150

Senior Member
Location
bay area, ca
Minuteman said:
If you use a DeWalt 18volt impact driver like this, it will! :cool:


DW056K-2_1.jpg


If you use a #10 screw to make the pilot hole, the greenie may be too loose. Self tapping greenies are tapered at the end and have cutting edges to cut the threads.

FWIW, There are two types of self tapping greenies. Both have the taper, but one has a large notch and the other has several lengthwise grooves. I prefer the ones with the notch.


.


Hey I got one or 2 of those in here somewhere....

DSC00278_resize.JPG


:grin: :grin: :grin:


~Matt
 

iwire

Moderator
Staff member
Location
Massachusetts
Matt, some might say you have an obsession and that you might need help. :D

Me....I am just jealous. :mad:

How come only two look (slightly) used?

How is the power center / charger / light thing? I just saw an ad for one last week and it looked interesting.


BTW.....where is the radio? :cool:
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I don't think Matt uses those tools either. He either just bought them or they are his desk decorations.:grin:

I have never seen or used a 4 gang receptacle plate---special order on that one???
 

DPW

Member
Location
FT. SMITH, AR
Source Of Self Drilling Machine Screw

Source Of Self Drilling Machine Screw

From the previous threads, I have not had any success finding a source of a 10/32 self drilling, self tapping machine screw.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
DPW said:
From the previous threads, I have not had any success finding a source of a 10/32 self drilling, self tapping machine screw.
mcmaster carr even has green ones!

Green Chromate Zinc-Plated Finish
3/8" 92597A400 $6.82 per Pack of 25

1/2" 92597A500 6.99 per Pack of 25
 
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