Grounding 2 gang Duplex

[scout4bta]

When tying the grounds in a 2 gang duplex do I need to tie the ground wires together and to the box or can I tie the gnd to each duplex as I've done. This is a detached steel workshop. I would think that the with all the 'steel' that that would be sufficient grounding.
The box is for led lighting on the ceiling.

 

[alfredeneuman]

All the grounding wires need to be attached to each other. (w/wirenuts or crimp connectors)
There is a 10-32 threaded hole in the back of the box, which is meant for a ground screw.
You've got to ground (bond) the box, and both of the receptacles as well

 

[sberry]

To add to this if the devices were screwed in to the box it may be done differently but with the detached cover it needs a wire to the box too.

 

[scout4bta]

Thanks for the info.

 

[Bert_]

Removing a device should not interrupt the ground path. Plus your box needs a ground screw and jumper.

If those are self grounding receptacles then you could simply ground the metal box and forgo the wire to the receptacle.

For stuff like this I really like just using the pipe ground instead of running a wire. eliminates so much work and the pipe is a better conductor anyway.

 

[ford33]

With EMT used from the breaker box to the metal receptacle boxes why is it necessary to have a separate ground wire to the receptacles? This is assuming self grounding receptacles and well constructed EMT installation.

 

[TRWham]

With EMT used from the breaker box to the metal receptacle boxes why is it necessary to have a separate ground wire to the receptacles? This is assuming self grounding receptacles and well constructed EMT installation.

It's not necessary. EMT is an approved EGC.

 

[scout4bta]

Yes these are self grounding outlets. All wiring is in metallic conduit. So according to 'code' I can forgo the gnd wire to the outlets but tie the gnd wires together along with a gnd wire from the box?

 

[ford33]

i am not a licensed electrician but I am familiar with this installation. If metal conduit is used everywhere a separate ground wire is not necessary. I do not use a ground wire to the outlets. They are grounded when installed in the metal box.

 

[teamextreme]

Yes these are self grounding outlets. All wiring is in metallic conduit. So according to 'code' I can forgo the gnd wire to the outlets but tie the gnd wires together along with a gnd wire from the box?

No, you can eliminate the ground wires being pulled through the conduit. The conduit serves as the "ground wire". The receptacles still need to be grounded. Since you have self grounding outlets they would not need any ground wire IF you are using a mud-ring to install them. For a raised cover installation, which you are using, it will require ground jumpers from the receptacles to a ground screw mounted in the box.

 

[scout4bta]

No, you can eliminate the ground wires being pulled through the conduit. The conduit serves as the "ground wire". The receptacles still need to be grounded. Since you have self grounding outlets they would not need any ground wire IF you are using a mud-ring to install them. For a raised cover installation, which you are using, it will require ground jumpers from the receptacles to a ground screw mounted in the box.

I did not mean to imply not pulling the ground wire through conduit, I definitely have the ground wire in conduit. I was talking about not connecting the gnd wires to the outlet because the outlets are self grounding, connecting the gnd wire to the box and also to the gnd wires.

 

[rabidsquirrel]

No, you need a ground wire from the receptacles to the box. Once you pull that cover off the receptacles are no longer grounded if you rely on the self grounding feature.

Sent from my VS987 using Tapatalk

 

[theoldwizard1]

Removing a device should not interrupt the ground path. Plus your box needs a ground screw and jumper.

If those are self grounding receptacles then you could simply ground the metal box and forgo the wire to the receptacle.

Is this still legal ? Maybe I have been using too many plastic boxes !

 

[alfredeneuman]

To qualify for grounding (without the jumpers) both the box and the cover need to be listed for grounding path with each other.
Each listing costs about $20K and the listing is just for that particular box/cover combination.
That's why few (I know of none) are listed.

 

[exranger06]

I did not mean to imply not pulling the ground wire through conduit, I definitely have the ground wire in conduit. I was talking about not connecting the gnd wires to the outlet because the outlets are self grounding, connecting the gnd wire to the box and also to the gnd wires.

We know what you were implying. What teamextreme is trying to say is, you do not need to pull a ground wire through conduit. You could pull all of the ground wires out of your conduit right now, and you'd still be code-compliant. This is because the conduit itself can act as a ground conductor, as long as you have a continuous metallic path all the way back to the panel. If you do decide to remove the ground wires, all you would have to do is run a ground wire from the receptacle to the ground screw on the box.

Of course you can keep the ground wires in the conduit if you want. In that case, install a jumper to the screw on the box and jumpers to each receptacle and tie them all together.

 

[checkthisout]

To summarize:

1)Pull the green ground wires out and save them for a rainy day.

2) Buy green grounding screws and put them in the threaded hole in the box marked "GND" and run pigtails from the green grounding screws you have just installed on the boxes to the green screws on the outlets.

3) Make sure your conduit is grounded and connected properly to all boxes so that it acts as ground back to the source.

 

[sberry]

I don't use a green especially since this is all screwed to a steel building.

 

[scout4bta]

Even bought the green ground screws.
Every thing is grounded.
Only have 5-6 more to go.

 

[sberry]

Reminds me that I need to buy a box. Getting to the bottom and sorting.

 

[Bert_]

No, you can eliminate the ground wires being pulled through the conduit. The conduit serves as the "ground wire". The receptacles still need to be grounded. Since you have self grounding outlets they would not need any ground wire IF you are using a mud-ring to install them. For a raised cover installation, which you are using, it will require ground jumpers from the receptacles to a ground screw mounted in the box.

Since the raised cover he is using have the recessed corners you do not have to jumper the receptacle to the box. The recessed corners provide a solid connection compared to raised covers without.

There is reference to this in the NEC but I'd have to do some digging to find the section

 

[grounded-b]

No, you can eliminate the ground wires being pulled through the conduit. The conduit serves as the "ground wire". The receptacles still need to be grounded. Since you have self grounding outlets they would not need any ground wire IF you are using a mud-ring to install them. For a raised cover installation, which you are using, it will require ground jumpers from the receptacles to a ground screw mounted in the box.

 

[egdede]

Bert, why do you say conduit is a better conductor than copper wire?

 

[sberry]

They tested this, some reason about fields and such stuff I don't know much about but it trips the breaker faster. Either is legal.

 

[dscheidt]

Bert, why do you say conduit is a better conductor than copper wire?

Huge cross section gives it much lower impedance. The purpose of the safety ground is to flow enough current to trip the breaker in the event of the short, and do it fast. Metal conduit does that better than copper wire; even if a ground wire is present, the conduit will carry the majority of the fault current. Grounds are used by people who don't believe that, and for redundancy (if the conduit it broken, it won't clear a fault, and will shock you.) in industrial and outdoor applications.

 

[egdede]

I'm surprised...In the future, I suspect I'll still pull a wire through existing conduit out of an abundance of caution.

 

[grounded-b]

Since the raised cover he is using have the recessed corners you do not have to jumper the receptacle to the box. The recessed corners provide a solid connection compared to raised covers without.

There is reference to this in the NEC but I'd have to do some digging to find the section

No, you still need to use a pigtail from each receptacle to the box, when using ANY raised covers. If the corner cover screws become loose, bonding is compromised. The NEC reference has to do with FLUSH (in-wall) mounted devices making solid contact with the metallic box. No ground wire is needed in that case.

Steve
JW

 

[Bert_]

No, you still need to use a pigtail from each receptacle to the box, when using ANY raised covers. If the corner cover screws become loose, bonding is compromised. The NEC reference has to do with FLUSH (in-wall) mounted devices making solid contact with the metallic box. No ground wire is needed in that case.

Steve
JW

250.146(A) says you don't have to if the recepacle is attached to the cover with at least two screws and when the cover screws are located in a non raised portion.

 

[grounded-b]

250.146(A) says you don't have to if the recepacle is attached to the cover with at least two screws and when the cover screws are located in a non raised portion.

No. The exception doesn't say "device attached with two screws", it says two PERMANENT fasteners, such as RIVITS, or a thread locking means.

I agree about the flattened corners of the cover, meeting the first half of the exception, but the second part talks about a LISTED box AND cover combination, providing satisfactory ground continuity.

Steve
JW

 

[mm08822]

no. The exception doesn't say "device attached with two screws", it says two permanent fasteners, such as rivits, or a thread locking means......continue reading the rest of the article.

i agree about the flattened corners of the cover, meeting the first half of the exception, but the second part talks about a listed box and cover combination, providing satisfactory ground continuity.

Steve
jw

and the mfr's spec sheet.......no jumper required.

 

[grounded-b]

and the mfr's spec sheet.......no jumper required.

You are 100% correct, IF you are using Raco ( or other approved ) covers.

Not all covers come with lock washers. Steel City RS-12's come with stamped steel nuts (no LW's )

I'll always put the jumper in, just so I'm covered

Steve
JW