# Self grounding outlet with screws only



## Coppersmith (Aug 11, 2017)

If you are mounting a device on a metal box, then the two #6 screws that hold the device to the box are acceptable for self-grounding as long as you remove the little plastic squares that keep the screws from falling out.

If you are mounting the device in an RS cover, then you must use two #6 screws and nuts to securely fasten the device to the cover. The center screw for receptacles can be installed, but doesn't count toward grounding.

The box itself must be grounded for self-grounding to work. You can attach the ground wire to the box using a grounding screw or a grounding clip.

Obviously, but I will state it for completeness, if you are using a plastic box, self-grounding doesn't work.


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## HertzHound (Jan 22, 2019)

The difference is that a switch is just a switch. A receptacle is used to extend the wiring to a piece of equipment. So having a good ground to a receptacle is paramount.


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## vibrantoyster (Jul 18, 2021)

Coppersmith said:


> If you are mounting a device on a metal box, then the two #6 screws that hold the device to the box are acceptable for self-grounding as long as you remove the little plastic squares that keep the screws from falling out.


In reality, most of the metal boxes are not flush with the wall or had some paint on them, so the only metal-to-metal connection between the receptacle and the box is through the #6 screws and their threads, not yoke to the box, etc.

Is that acceptable for self-grounding?


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## Coppersmith (Aug 11, 2017)

vibrantoyster said:


> In reality, most of the metal boxes are not flush with the wall or had some paint on them, so the only metal-to-metal connection between the receptacle and the box is through the #6 screws and their threads, not yoke to the box, etc.
> 
> Is that acceptable for self-grounding?


I would scrape the paint off the tab if you want to maximize the grounding potential, but in reality the screw itself will conduct sufficient amps to ground the device properly. Code compliant without scraping? Probably not.


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## 99cents (Aug 20, 2012)

You don’t have the clip on the yoke on one of the screws for bonding?


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## HertzHound (Jan 22, 2019)

vibrantoyster said:


> In reality, most of the metal boxes are not flush with the wall or had some paint on them, so the only metal-to-metal connection between the receptacle and the box is through the #6 screws and their threads, not yoke to the box, etc.
> 
> Is that acceptable for self-grounding?


I wouldn’t consider it acceptable if the yoke did not sit on the box. It’s not worded well and may be open to interpretation. In my opinion the self grounding clip is there to hold the screw in place during shipping. Similar to the fiber washer. The difference is that if someone was saving time not using an equipment bonding jumper, they are wasting time having to remove the fiber washer. With the clip, the screw is held in place without having to remove anything. But the yoke still has to sit on the box regardless of how the screws are held in during shipping. The self grounding clip is also mentioned in surface mounted boxes. In this case they are probably talking about “FS” “FD” etc. type boxes, not 4” squares.

Maybe looking it up in the UL white book would really solve the question?


*250.146 Connecting Receptacle Grounding Terminal to Box.*
An equipment bonding jumper shall be used to connect the grounding terminal of a grounding-type receptacle to a grounded box unless grounded as in 250.146(A) through (D). The equipment bonding jumper shall be sized in accordance with Table 250.122 based on the rating of the overcurrent device protecting the circuit conductors.
*(A)Surface-Mounted Box.*
Where the box is mounted on the surface, direct metal-to-metal contact between the device yoke and the box or a contact yoke or device that complies with 250.146(B) shall be permitted to ground the receptacle to the box. At least one of the insulating washers shall be removed from receptacles that do
not have a contact yoke or device that complies with 250.146(B) to ensure direct metal-to-metal contact. This provision shall not apply to cover-mounted receptacles unless the box and cover combination are listed as providing satisfactory ground continuity between the box and the receptacle. A listed exposed work cover shall be permitted to be the grounding and bonding means when (1) the device is attached to the cover with at least two fasteners that are permanent (such as a rivet) or have a thread locking or screw or nut locking means and (2) when the cover mounting holes are located on a flat non-raised portion of the cover.
*(B)Contact Devices or Yokes.*
Contact devices or yokes designed and listed as self-grounding shall be permitted in conjunction with the supporting screws to establish equipment bonding between the device yoke and flush-type boxes.


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## vibrantoyster (Jul 18, 2021)

99cents said:


> You don’t have the clip on the yoke on one of the screws for bonding?


Nope, which means that when the receptacles were installed the electrician that did the work used non self grounding receptacles but decided to grounded them via the mounting screws anyway or maybe back then self grounding receptacles didn't come with the grounding clip. The receptacles look fairly new/modern, it's the Lutron TR but they don't have the self grounding clip. All the boxes are metal and the wiring is BX and grounded in the panel so when checked with a receptacle tester is shows that they are all grounded but the main question is what happens in case of a serious fault when this ground connection should save life, if this type of ground just via contact of the mounting screw will work?


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## SWDweller (Dec 9, 2020)

I maintain that all outlets should have a ground wire attached to them. Just like all conduit should have a ground wire. The use of a ground wire solves a lot of problems long before they rear their ugly little heads. Use of self grounding equipment then becomes just another path. I do not see it as a savings. Decades passed for me before any self grounding equipment made the market place. Old habits die hard.


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## 99cents (Aug 20, 2012)

This is easy. Use a plastic box with a bonding strap and a self bonding device. We have discussed this before and everybody agreed that the Canadian plastic boxes are pure genius.


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## HertzHound (Jan 22, 2019)

99cents said:


> This is easy. Use a plastic box with a bonding strap and a self bonding device. We have discussed this before and everybody agreed that the Canadian plastic boxes are pure genius.


A plastic box with the OP’s armored cable? Here we go. Another thread that’s run it’s course and can now go sideways. Any way we can bring weed into this thread?


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## 99cents (Aug 20, 2012)

HertzHound said:


> A plastic box with the OP’s armored cable? Here we go. Another thread that’s run it’s course and can now go sideways. Any way we can bring weed into this thread?


You just had to ask. 🤣


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## joe-nwt (Mar 28, 2019)

DaveSmithJr said:


> There is not as much voltage in light switches as in conventional sockets, this is due to the fact that lamps need about 50 volts to light up, and sockets contain about 220 volts of voltage.


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## macmikeman (Jan 23, 2007)

Dave always was at the very top of the class............


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## Dennis Alwon (May 9, 2009)

DaveSmithJr said:


> There is not as much voltage in light switches as in conventional sockets, this is due to the fact that lamps need about 50 volts to light up, and sockets contain about 220 volts of voltage.



David this site is for electricians. Clearly you are not or you are trolling. In either case please refrain from posting here. TY


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## joe-nwt (Mar 28, 2019)

gruehwing said:


> There is not as much voltage in light switches as in conventional sockets, this is due to the fact that lamps need about 50 volts to light up, and sockets contain about 220 volts of voltage.


Good morning Dave, 

Shall. We. Play. A. Game?


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