Grounding Conduit for Multiple Circuits.

[checkthisout]

So if you have two circuits entering a metal box, both NM cables, you then run conduit down to another box where you have a plug (on one circuit) and say a light switch on the other.

At the first box, do both grounds need to be connected to the box? If so, do both wires need to be attached to the screw or can you put a say a 12 gauge under the screw then wire nut both grounds (say a 14 gauge and a 12 gauge) wire to the single 12 gauge?

Basically, you can use the conduit as the ground without running grounding conductors through the conduit, so what's the proper way of grounding the first box where the circuits enter when your conduit doesn't run all the way back to the panel?

 

[wyliesdiesels]

Is this metal conduit?

If so, u could omit all EGC wires and use the conduit as the EGC.

Or u can use one wire for multiple circuits sizing the EGC based on the largest breaker size.

As far as bonding the boxes, yes u can use a pigtail- one wire to ground screw spliced to 2 wires in a wire nut. Or use a greenie and forgo the pigtail lead. This will save room in the box.

Multiple ways to do it.

 

[checkthisout]

Does this apply?

Enclosures for Grounding Electrode Conductors Ferrous metal enclosures for grounding electrode conductors shall be electrically continuous from the point of attachment to cabinets or equipment to the grounding electrode and shall be securely fastened to the ground clamp or fitting. Nonferrous metal enclosures shall not be required to be electrically continuous. Ferrous metal enclosures that are not physically continuous from cabinets or equipment to the grounding electrode shall be made electrically continuous by bonding each end of the raceway or enclosure to the grounding electrode conductor. Bonding shall apply at each end and to all intervening ferrous raceways, boxes, and enclosures between the service equipment and the grounding electrode. The bonding jumper for a grounding electrode conductor raceway or cable armor shall be the same size as, or larger than, the required enclosed grounding electrode conductor. Where a raceway is used as protection for a grounding electrode conductor, the installation shall comply with the requirements of the appropriate raceway article

From this it looks like I would need to bond all the boxes in the run with a single ground running back to the first box since my conduit is not continuous back to the breaker panel?

 

[wyliesdiesels]

Does this apply?

Enclosures for Grounding Electrode Conductors Ferrous metal enclosures for grounding electrode conductors shall be electrically continuous from the point of attachment to cabinets or equipment to the grounding electrode and shall be securely fastened to the ground clamp or fitting. Nonferrous metal enclosures shall not be required to be electrically continuous. Ferrous metal enclosures that are not physically continuous from cabinets or equipment to the grounding electrode shall be made electrically continuous by bonding each end of the raceway or enclosure to the grounding electrode conductor. Bonding shall apply at each end and to all intervening ferrous raceways, boxes, and enclosures between the service equipment and the grounding electrode. The bonding jumper for a grounding electrode conductor raceway or cable armor shall be the same size as, or larger than, the required enclosed grounding electrode conductor. Where a raceway is used as protection for a grounding electrode conductor, the installation shall comply with the requirements of the appropriate raceway article

From this it looks like I would need to bond all the boxes in the run with a single ground running back to the first box since my conduit is not continuous back to the breaker panel?

No that doesn't apply. you're confusing different things.

A grounding electrode conductor is the conductor that connects grounding electrodes aka grounding rods to the main service panel.

That has nothing to do with grounding conductors for branch circuits.

But since conduit isnt continuous metal then u cant use the conduit as an EGC and would need a grounding conductor.

U could still use a single grounding conductor for multiple circuits. Say u have multiple circuits and the largest is 20a, then u can use 1 #12 green wire and splice it to multiple circuit's EGC wires in the first junction box where they all meet.

for larger circuits and EGCs refer to nec table 250.122

 

[sberry]

If you are using cables ground both circuits to the box. You can wire nut them all together and connect one to the screw.

 

[checkthisout]

If you are using cables ground both circuits to the box. You can wire nut them all together and connect one to the screw.

That's what I did. It's a 15 and 20 amp circuit. I bunched all the grounds together in the first box then ran a pigtail to the box screw.

All my devices at the downstream boxes just pigtail directly to the boxes. No grounding conductor is running between any of the boxes.

I also did the same thing on the light circuit for the nuetrals. I did run a single nuetral down to the switch box though. Need a neutral for zwave.

 

[minytrker]

I ran a ground from the breaker box ground bar to every outlet and light. Is there anything wrong with doing it that way?

 

[wyliesdiesels]

I ran a ground from the breaker box ground bar to every outlet and light. Is there anything wrong with doing it that way?

no.

Just more wire and obviously added cost

 

[penright]

U could still use a single grounding conductor for multiple circuits. Say u have multiple circuits and the largest is 20a, then u can use 1 #12 green wire and splice it to multiple circuit's EGC wires in the first junction box where they all meet.

My panel is in the middle. I was coming out of it with two circuits to two different GFI. Then branching off of it to other outlets, one GFI for outlets to the left and the other for outlets to the right. All is #12 solid copper in EMT, 4" square boxes, and industrial surface mount covers.
Could I have used the EMT as ground, IOW no green wire?
I have already started pulling ground wires anyway, do I need to bond them to the box also?

 

[sberry]

If you are pulling a wire it needs to bond to the box and then a jump to anything cover mounted. Some self grounding outlets may be installed without it provided they mount to the box vs the cover. In a steel building where I am piping I don't run a wire unless I have to or there is some legit reason it may have the potential for becoming disconnected. Steel to steel with the pipe clamped and boxes screwed to the frame it doesn't matter much and there is some argument that it may be even better. I don't know enough about it to qualify that comment so fwiw.

 

[penright]

If you are pulling a wire it needs to bond to the box and then a jump to anything cover mounted.

I bought a package of greenie wire nuts, thinking that would do it.

Unless there is some trick to share, I guess I need to get a package of these?https://www.lowes.com/pd/IDEAL-25-Count-Hook-Wire-Connectors/999959299

Or do not pull a ground?

 

[aandpdan]

Penright, you don't need the green ground wire - the conduit itself is sufficient.

If you choose to use the grounds, bond them to the box.

 

[mm08822]

Penright, you don't need the green ground wire - the conduit itself is sufficient.

If you choose to use the grounds, bond them to the box.

And 1 ground wire is more than enough when your running emt. Don't use your conduit fill on needless ground wires.

 

[checkthisout]

Looks good Pen. No need for the ground wires.

 

[wyliesdiesels]

My panel is in the middle. I was coming out of it with two circuits to two different GFCIs. Then branching off of it to other outlets, one GFCIs for outlets to the left and the other for outlets to the right. All is #12 solid copper in EMT, 4" square boxes, and industrial surface mount covers.
Could I have used the EMT as ground, IOW no green wire?
I have already started pulling ground wires anyway, do I need to bond them to the box also?

If the EMT is complete then yes u can forgo the ground wires.

No u dont need a ground wire for each circuit. As i said above u could use one ground wire for multiple circuits. Just size the wire correctly.

And if the outlets are self grounding and mount to the box as Sberry pointed out above, then u dont need a ground wire on the either.

In your case looks like you will need a pigtail from the outlet to the box ground screw. So u could make your own or buy the premade ones u linked to below.

I bought a package of greenie wire nuts, thinking that would do it.

Unless there is some trick to share, I guess I need to get a package of these?https://www.lowes.com/pd/IDEAL-25-Count-Hook-Wire-Connectors/999959299

Or do not pull a ground?

The greenies are easy. Just have to strip about 4" of insulation off one of the wires and run it through the hole. Then put a loop in the end and wrap it around the green ground screw. Or u can use the premade ones.

As they say, there is multiple ways to skin a cat.

 

[barnjunkie]

I bought a package of greenie wire nuts, thinking that would do it.

Unless there is some trick to share, I guess I need to get a package of these?https://www.lowes.com/pd/IDEAL-25-Count-Hook-Wire-Connectors/999959299

Or do not pull a ground?

I have ground wires included in my conduit runs as well. Its overkill and not required, but since I had the wire.....
I have never seen jboxes under the window like the one in your photo. I hope that works

 

[sberry]

I want to go back to the OP. It described 2 cables and connecting the grounds together. While a single ground or the pipe could be used since this is 2 cables and not single conductors in pipe the grounds in the cables should be used. Not sure this will make sense.

 

[rharman]

Is this metal conduit?

If so, u could omit all EGC wires and use the conduit as the EGC.

Or u can use one wire for multiple circuits sizing the EGC based on the largest breaker size.

As far as bonding the boxes, yes u can use a pigtail- one wire to ground screw spliced to 2 wires in a wire nut. Or use a greenie and forgo the pigtail lead. This will save room in the box.

Multiple ways to do it.

Well, I just learned something new. Don't know why I've never known about these. Sure could have used them a few times.

 

[penright]

I have never seen jboxes under the window like the one in your photo. I hope that works

I assume you are talking about the one that is not mounted. It will be for my low voltage connections. I also have a 1" conduit running alongside the one for electrical service. The low voltage will be for IP and alarm. I am not too far from the house for WIFI, just will not go through the metal building.

I have some RG59 left over from previous endeavors. Two issues, one do I have enough to run from the house to the shop. Will the signal be strong enough at that distance (guessing about 225'). So at least I will have two Cat 5 and maybe a RG59. I could mount an antenna on the outside, just did not want it sticking up there. That will get me local channels. Then some day when we get faster internet I can stream ESPN and Fox sports. All that is WAY in the future.

 

[penright]

Looks good Pen. No need for the ground wires.

In your case looks like you will need a pigtail from the outlet to the box ground screw.

After further review, the call is changed. Well kind of, I went with running the ground only because I had the wire bought and would never use it otherwise.
It is nice to know I only needed the one, as mentioned it saves room in my chases.
So I did not feel so dumb spending money that didn't need to be ....
By telling myself that it won't hurt in case some conduit came loose.

 

[matt_i]

My personal feeling is you are doing a good job when you have an actual copper wire as your ground conductor that eventually terminates at a metal stick in the earth, bonded to each metal enclosure and device that has a green screw. I recognize the letter of the code as not requiring it with conduit but better work can be done for what I feel is infinitesimal extra cost.

 

[mjbasford]

I have some RG59 left over from previous endeavors. Two issues, one do I have enough to run from the house to the shop. Will the signal be strong enough at that distance (guessing about 225'). So at least I will have two Cat 5 and maybe a RG59. I could mount an antenna on the outside, just did not want it sticking up there. That will get me local channels. Then some day when we get faster internet I can stream ESPN and Fox sports. All that is WAY in the future.

Rg59 is no longer recommended for standard house runs, let alone this distance. Use rg6 at minimum, but I would recommend rg11 at that length.

 

[wyliesdiesels]

Rg59 is no longer recommended for standard house runs, let alone this distance. Use rg6 at minimum, but I would recommend rg11 at that length.

I assume you are talking about the one that is not mounted. It will be for my low voltage connections. I also have a 1" conduit running alongside the one for electrical service. The low voltage will be for IP and alarm. I am not too far from the house for WIFI, just will not go through the metal building.

I have some RG59 left over from previous endeavors. Two issues, one do I have enough to run from the house to the shop. Will the signal be strong enough at that distance (guessing about 225'). So at least I will have two Cat 5 and maybe a RG59. I could mount an antenna on the outside, just did not want it sticking up there. That will get me local channels. Then some day when we get faster internet I can stream ESPN and Fox sports. All that is WAY in the future.

RG59 hasnt been used for Cable TV for decades. It doesnt have the bandwidth that RG6 has.

Throw it in the scrap pile and buy at least RG6 but as said above that distance may necessitate RG11.

 

[penright]

Rg59 is no longer recommended for standard house runs, let alone this distance. Use rg6 at minimum, but I would recommend rg11 at that length.

RG59 hasnt been used for Cable TV for decades. It doesnt have the bandwidth that RG6 has.

Sorry for hijacking the thread. I have a bad habit for bunny trails. As I said, it not what I would have bought, just what I had. I am glad you guy pointed out the facts in case someone else comes along at a later date.

You all are correct when you say decades, I have had it close to 30 years. When I said past endeavor, I was talking long time ago in a galaxy far away.
If and when the time comes, I will look at it having it's own antenna for local stations. If and when I do put a TV out there, I can stream most of what I want. I hope we have faster internet by summer.

First, I need to focus on finish wiring and building shelves. Most of the outlets are done, waiting on some free light fixtures for the rest. Started playing with shelves last night.

:Throw it in the scrap pile

Done.