Eddy Current
Senior Member
I did see that in the Mike Holt book, and it said it was for the purpose of working on the receptacle without breaking the ground fault circuit.
Does grounding for four receptacles pigtail have to be a green screw?
- Thread starter Eddy Current
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I did see that in the Mike Holt book, and it said it was for the purpose of working on the receptacle without breaking the ground fault circuit.
- Location
- Massachusetts
The wire must be green or bare, the hardware connecting the wire to the box may be any color or no color at all.
- Location
- Massachusetts
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Removal of the device is not permitted to interrupt the continuity of other portions of the equipment grounding conductor - that is likely what was being mentioned, there are several possibilities of how all the items required to be bonded to the EGC could be done and not every installation will have all the same conditions either. But in general that is why there is only a single lead or jumper going to the receptacle itself.
No color at all - would seem to me it is either transparent or missing
- Location
- Massachusetts
Transparent would be legal. :thumbsup:
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Never said it wasn't, just a possible condition.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
But if you use transparent aluminum, just make sure that all the stuff that goes with it is Al/Cu listed.
mjf
Senior Member
If a screw is missing from a receptacle I generally circular file it. The time to "fix it" usually costs more than the receptacle.
K8MHZ
Senior Member
- Occupation
- Electrician
As you well should.
Just being picky here.
A UL listed receptacle will have terminal screws that are 'not readily removable'. Take a receptacle (I just did this) and try to spin a loose terminal screw all the way out with just your fingers. You should not be able to, as the threads on the screw are crimped so it can't be taken out without damaging the threads in the receptacle, and you would need a screw driver to do that.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
And if you did remove the original screw and then manage to thread in a replacement, it would no longer be "not readily removable" unless you could figure out a way to crimp the threads after inserting the screw. :roll:
And even that is assuming that all you damaged was the threads on the screw and not the threads in the receptacle body.
K8MHZ
Senior Member
- Occupation
- Electrician
That's right!!
You probably would have twisted the threaded tabs around a little, too.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Listing requirements may have changed over the years. Seems like it is easier to remove and successfully reuse said screw on some older devices then it is on most newer devices.
K8MHZ
Senior Member
- Occupation
- Electrician
The listing may have changed, or the screws have been backed out and put back in.
Or both. I have some very old receptacles in the garage. One of these days (not today) I'll pull one and check it out.
Just as a trivia question, I wonder when 'not readily removable' requirement was first in the books.
Eddy Current
Senior Member
So why is it against code to use a 5/16 self taping screw to the box as your pigtail? Wouldnt that be threaded?
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
Number of threads engaged in box wall thickness with coarser thread of larger screw?
Tapatalk!
Tapatalk!
- Location
- Massachusetts
It depends on the thread pitch and box thickness.
Most self tapping screws have a very coarse thread on them and cannot be used for grounding.
However, you can buy self drilling / tapping screws with standard machine threads on them, 10-32, 1/2"x20 etc.. Those can be used for grounding.
K8MHZ
Senior Member
- Occupation
- Electrician
The number of threads won't be in compliance. I don't know the exact article, but there must be at least 3 threads in the metal. The threads in a 5/16 not only have too coarse of threads, but they aren't machine threads.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
code reference to previous answers:
Two threads of the typical 10-32 screw that is commonly used is 2/32 = 1/16 inches. That means the box thickness has to be 1/16 inch or you will not get enough threads engaged with that type of screw to meet this code section. I believe that is part of reason why it is more common to see a raised bump in many boxes today where they intend you to install a grounding screw, as I wouldn't be surprised to see the wall thickness being less then 1/16 inches.
Not sure exactly when it was added but older codes did not have condition 6 which does allow a self tapping screw, but still requires it to have fine enough threads to have two threads engaged when installed.
Other listed means would work if you found a self tapping screw that was listed for the purpose - but I would guess you won't find any.
arknack
Member
- Location
- Jackson, MI
Grounding raised bump
Grounding raised bump
Actually, I thought the raised bumd was there to provide clearance for the screw projection so you wouldn't have to drill a divit in a concrete wall to mount the box.
Grounding raised bump
Actually, I thought the raised bumd was there to provide clearance for the screw projection so you wouldn't have to drill a divit in a concrete wall to mount the box.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
It comes in handy for that, but that may not be the only reason for it. Like I said if the box thickness isn't 1/16 inch then you don't have enough threads to meet code, but those raised bumps are always thicker then the rest of the box. And like everything else I can see them making boxes out of thinner material then they used to for saving a little on cost. I have not measured the thickness of any so I don't know how thick they are.
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