Ground screws?

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nunu161

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Why do we use green ground screws when NEC 250.148(C), just says as long as its a screw dedicated for the purpose?
 
nunu161 said:
Why do we use green ground screws when NEC 250.148(C), just says as long as its a screw dedicated for the purpose?
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Because they come in green. I guess you can go buy some screws that aren't green. I believe at one time the code required green screws but I may be wrong about that.
 
i was always told to use a green ground screws but after reading that section i think using a tex screw wouldn't be a violation
 
The screws that come with 4 x 4 troughs are the same thread as a grounding screw. Sometimes the factory workers put double parts bags.. now there is a use for them :grin:
 
Dennis Alwon said:
I don't think a tex screw has the required threads.
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Dennis hit on something I have heard, if anyone can elaborate please do.

Here goes:

Ground screws are supposed to have 3 threads in contact with the box/enclosure, hence the fine thread. The reasoning for this is that a threaded connection would require more torque to strip out. A sheet metal screw has less threads and could be stripped out easier causing a loose connection.

Seems logical, not sure how accurate this is.
 
KevinVost said:
Dennis hit on something I have heard, if anyone can elaborate please do.

Here goes:

Ground screws are supposed to have 3 threads in contact with the box/enclosure, hence the fine thread. The reasoning for this is that a threaded connection would require more torque to strip out. A sheet metal screw has less threads and could be stripped out easier causing a loose connection.

Seems logical, not sure how accurate this is.
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Pretty close, two threads. 250.8 (5 and 6). 2008

10-32 in 1/16" steel = two threads.
 
I always carry Gnd screws because they are 10/32 same as most dead front screws and for some reason electricians always seem to lose or are just two lazy to replace all four screws I like them all installed.

Good question for masters exam.

What color are green ground screws.


If you get this wrong the boot you out the door.
 
Green screws are mentioned twice in the '08:

250.28(B) and 250.156.

Manufacturers probably just make 'em green because "Green is ground".

I can't find any reference in any of the old Codes requiring a normal, run-of-the-mill ground screw to be green. Of course, Art. 250 is pretty big, gets changed a lot, and is hard to search using my computer since they don't fit in my CD tray very well.

Failing all else, without green ground screws, how can we stump cubbies with "What color is the green ground screw?" if the screws aren't green?
 
Green ground screws are not listed...;)



Green ground clips are listed...:-?


250.8 requires exothermic welding, listed pressure connectors, listed clamps or other listed means. [05]


250.8
Listed pressure connectors
Terminal bars
Pressure connectors listed...
Exothermic welding
Machine screw-type fasteners that engage not less than two threads or are secured with a nut
thread-forming machene screws that ...
Connections that are part of listed assembly
other listed means
[08]

The 08 requirements are much different than the 05
 
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