Wiring a 4-switch box with three incoming circuits

[RaysnCayne]

Hey all,

I guess I'm not plugging in the right search info so if this question has been answered, please feel free to link me to it.

I've got a 4-switch box I'm putting in my new garage that has three incoming circuits. (I'm only gonna have a grand total of seven 8' fluorescents in the shop, so I'm pretty sure I've "over-circuited" this setup, but what's run is run.) And now I'm trying to figure out how to wire it.

I have two circuits coming in for the seven lights (4 on one, 3 on the other) and then a third for my exterior lights (which are obviously going to be switched). I'm pretty sure I need to keep my neutrals separate, but what about my grounds? Do I have to twist all seven grounds together and make a pigtail to run across all four switches? That just seems like a lot of wires twisted together to me. I have a pack of those green wire nuts with the hole in them for this purpose, but I don't think it'll hold seven wires. Do I need to break them down? Like twist 3 together then 4 together then twist those two together to get one pig tail?

 

[jeffmoss26]

You can get large gray or blue wirenuts. Gardner Bender #89, Ideal #342 or #454.
I'd say the less connections, the less points of failure.

 

[MrMark]

green nuts are only listed for 4 #12 as I recall. Yes, do what your last sentence states. You need to bundle the grounds into manageable units and then jumper them together.

On that box: anything over 2 gang is unstable and needs support at both ends to keep from rocking in the wall.

 

[RaysnCayne]

Thanks for the input guys. Bottom line is: get all the grounds twisted together one way or another.

I think I prefer the idea of twisting all 7 together and letting one run long (through a hole I'll drill in a big gray wire nut) just to keep it as lean as possible. [This is the very last box I gotta rough in. So buying a bag just for one nut *****. That's gonna be one expensive wire nut.]

@MrMark: Yepper, it's a 4 gang box with a tab on the right. Fits perfectly and very stably where I'm placing her in between a stud and jack stud (for the man door) situation.

 

[BigJohn20]

Thanks for the input guys. Bottom line is: get all the grounds twisted together one way or another.

I think I prefer the idea of twisting all 7 together and letting one run long (through a hole I'll drill in a big gray wire nut) just to keep it as lean as possible. [This is the very last box I gotta rough in. So buying a bag just for one nut *****. That's gonna be one expensive wire nut.]

You really think it's a good idea making your own greenie connector?

You're wiring a garage and you're balking at a wirenut you can pickup for under a couple of bucks in a multipack?

 

[Gooch]

since they are all seperate circuits(i.e. homeruns to the panel. you don't need to tie all the grounds to each other) just need to keep the circuits grounds together

 

[Norcal]

since they are all seperate circuits(i.e. homeruns to the panel. you don't need to tie all the grounds to each other) just need to keep the circuits grounds together

Incorrect,they need to be all connected together. Neutrals from different circuits should not be connected together.

 

[RaysnCayne]

I know, I know, what's $2.79 when I'm building a $13K garage? What can I say? I'm a cheapskate. But I'd like to think I'm a bit practical too.

I think I've got one gray wire nut in my misc. wire nuts bin. A small, cleanly-drilled hole in the tip is no different than a factory-made greenie. It's not that risky. It's fun and safe, kind of like electrical "hot rodding". ; ) And it'll save me the time/gas of another trip to Lowes and I won't have a nearly-full bag of wire nuts I'll never use.

 

[fefarms]

I politely disagree with JeffMoss26 on this. I've found it very difficult to get a 7 wire connection in a single wire nut to be electrically and mechanically secure. My usual practice is to group the grounds into manageable 3 or 4 wire connections, then tie the groups together electrically.

For that matter, I mostly use Wago wall nuts and not twist-on's anyway.

 

[jeffmoss26]

I just figured it would take less space in the box. No harm done!

 

[rlitman]

I've found it very difficult to get a 7 wire connection in a single wire nut to be electrically and mechanically secure.

It can be done.
Line up all the wires, twist them together so they look like one thick twisted wire (you do know that 7 stranded wires like 2 and 4 gauge are factory twisted from things like 12 and 14 gauge wires anyway), then cut the twisted bundle so everything ends together.
IF you just try to shove all the wires in to the nut, and some are longer than others, then it will not be reliable.

Look at the package for the wire nuts. It will explicitly state the complete list of exact combinations of wires that are allowed to be joined by it.
I would use a pigtail though, rather than modify a wire nut by drilling the end.

 

[Gooch]

Incorrect,they need to be all connected together. Neutrals from different circuits should not be connected together.

nec section?

 

[MrMark]

Is there even a nut listed for 7 #12? The bigger nuts I have seen do not have that listing. I would stick to the red ideal nut with 5 #12 as max.

 

[MrMark]

nec section?

I don't have an nec section but I can tell you that what he stated makes sense electrically. Of course, the neutrals must be kept separate between circuits, but on the grounds it makes sense to provide as many paths back to the panel for a fault as possible. If one circuit had a bad ground path the fault could clear through another circuit's ground path if they were tied together. I have never even thought about not tying them all together.

 

[Gooch]

I don't have an nec section but I can tell you that what he stated makes sense electrically. Of course, the neutrals must be kept separate between circuits, but on the grounds it makes sense to provide as many paths back to the panel for a fault as possible. If one circuit had a bad ground path the fault could clear through another circuit's ground path if they were tied together. I have never even thought about not tying them all together.

how is it any different than if i put up 4 single gang boxes instead of 1 single 4 gang box?(other than the box obviously.

Not saying it isn't in the code, I've just never seen it, it's possible I'm wrong.

 

[MrMark]

how is it any different than if i put up 4 single gang boxes instead of 1 single 4 gang box?(other than the box obviously.

Not saying it isn't in the code, I've just never seen it, it's possible I'm wrong.

You couldn't tie them if you put up 4 single gang boxes but that is not the situation presented. If you can tie them because you have that ability with the 4 gang box, I think you should for utmost in safety.

 

[Gooch]

You couldn't tie them if you put up 4 single gang boxes but that is not the situation presented. If you can tie them because you have that ability with the 4 gang box, I think you should for utmost in safety.

your opinion.

 

[ForceFed70]

your opinion.

It's not opinion, it's fact. Tying the grounds together whenever possible is a way to help ensure that there is always a ground path present.

 

[Falcon67]

When I have done this, I leave the grounds long and grab 'em up with lineman's pliers, then twist them all in. It can be done, PITA but with enough twists it'll be mechanically sound. Trim the twist and - optional - cap with a big grey or blue nut.

Every multi-gang box in this house is done like that too.

Now - if you ever go back in there to change things, you'll be sorry LOL. So leave the twist as long as you can, as long as it lays in the box out of the way.

 

[Gooch]

It's not opinion, it's fact. Tying the grounds together whenever possible is a way to help ensure that there is always a ground path present.

the feeds go back to the same place, if one is damaged they all will be. sure there are always the exceptions, but if done correctly, it's not any more dangerous than tying them all together.

 

[MrMark]

the feeds go back to the same place, if one is damaged they all will be. sure there are always the exceptions, but if done correctly, it's not any more dangerous than tying them all together.

Yeah, it's my opinion, but it's based on study and education and experience.

What you just said is not true. They will not all be damaged if one is. One circuit's ground could have an open path or a high resistance path on its way back to the panel whereas the other path from the other circuit is a good path. That is a very common scenario.

I have a feeling there is an NEC section on this. It's too obvious for there not to be. Maybe I will look tonight.

 

[Gooch]

Yeah, it's my opinion, but it's based on study and education and experience.

What you just said is not true. They will not all be damaged if one is. One circuit's ground could have an open path or a high resistance path on its way back to the panel whereas the other path from the other circuit is a good path. That is a very common scenario.

I have a feeling there is an NEC section on this. It's too obvious for there not to be. Maybe I will look tonight.

name how this is a common scenario.

aslong as it's a plastic box, they do not need to be all tied together, you can keep each circuit's grounds seperate inside the same box.

Like I said, it is no different than if I had 4 single gang boxes.

 

[MrMark]

It's not a common scenario for one circuit to have a bad ground on it's way back to the panel? You are seriously reaching on this one and it is not showing well for you. You should just admit you are wrong and move on. Nothing is more unappealing than someone who won't admit they are wrong.

 

[Gooch]

It's not a common scenario for one circuit to have a bad ground on it's way back to the panel? You are seriously reaching on this one and it is not showing well for you. You should just admit you are wrong and move on. Nothing is more unappealing than someone who won't admit they are wrong.

the only time i've had a ground be bad on the homerun, is when it was damaged after installation, which if that happens, the other two homeruns will be damaged as they will be run together.

using your logic, if it were in pipe, we shouldn't be allowed to use one ground for the entire pipe.

I agree, it's unappealing when someone won't admit they are wrong.

 

[MrMark]

try 250.148.

I guess you have it all figured out. I'm sure you've never damaged any wires in pipe when you installed them. Homeruns? lol. I love the term.

I also guess you've never run the "homerun's" in other than the famous pipe which has only one green wire? What about "homerun's" in romex or mc or anything other than "pipe." Could one of them have a bad ground on the way back to the panel, even if you didn't damage it?

I'm out. I could give a **** what you do. This is why I would never hire an electrician in the first place.

 

[Gooch]

try 250.148.

I guess you have it all figured out. I'm sure you've never damaged any wires in pipe when you installed them. Homeruns? lol. I love the term.

I also guess you've never run the "homerun's" in other than the famous pipe which has only one green wire? What about "homerun's" in romex or mc or anything other than "pipe." Could one of them have a bad ground on the way back to the panel, even if you didn't damage it?

I'm out. I could give a **** what you do. This is why I would never hire an electrician in the first place.

Is this the wording in your code book?

"Where circuit conductors are spliced within a box, or terminated on equipment within or supported by a box, any equipment grounding conductor(s) associated with those circuit conductors shall be connected within the box or to the box..."

 

[ForceFed70]

the only time i've had a ground be bad on the homerun, is when it was damaged after installation, which if that happens, the other two homeruns will be damaged as they will be run together.

The other 2 may be damaged. Maybe not. You can also have failures at any ground connector in the circuit (It's not uncommon to feed a light switch from a plug recepticle, etc).

Yes, it shouldn't happen but it does happen. Home inspectors and electricians run across open grounds all of the time. It's cheap (almost free) insurance and I just don't get why you are argueing against it.

 

[Gooch]

The other 2 may be damaged. Maybe not. You can also have failures at any ground connector in the circuit (It's not uncommon to feed a light switch from a plug recepticle, etc).

Yes, it shouldn't happen but it does happen. Home inspectors and electricians run across open grounds all of the time. It's cheap (almost free) insurance and I just don't get why you are argueing against it.

I was under the impression these were lighting only circuits and the feeds went back to the panel.

I'm not saying you have to do it my way, but to tell me my way is wrong, i think is incorrect. There is always more than one way to skin a cat. For me my way makes more sense, allows for easier install, easier changes/diagnostics, plenty safe(no more dangerous than if a person were to put 4 single gangs instead.)

 

[ForceFed70]

I was under the impression these were lighting only circuits and the feeds went back to the panel.

I'm not saying you have to do it my way, but to tell me my way is wrong, i think is incorrect. There is always more than one way to skin a cat. For me my way makes more sense, allows for easier install, easier changes/diagnostics, plenty safe(no more dangerous than if a person were to put 4 single gangs instead.)

I'm taking a more "in general" approach to the topic.

Easier diagnostics? How? We're talking ground path here there isn't much to diagnose. Easier install... maybe save you 30 seconds per box and I bet it's even quicker/easier for a competent electrician (1 ground wire nut vs multiple). I'm not sure how changes would be easier with the grounds tied together vs seperate. To me, the drawbacks you list are minor while the potential benifit is large.

Your way isn't wrong to my knowledge, although I was also under the impression that it was code to tie all of the grounds together. So long as there is a ground path, your way is also safe.

My point is that it's a better way to do things. I don't think that arguing that it's easier to undo/change or it saves you 15 minutes on an entire electrical project is reason enough for not doing something a better way in the 1st place. By that logic, adding extra rebar in a concrete slab isn't a good idea because you might need to pull it up one day. Or adding extra fasteners isn't a good idea. Etc.

 

[Provincial]

In wiring my shop, I bought a crimper and crimp sleeves (two sizes) that is made for binding the ground wires together. When I have multiple switches or recepticles, I leave the entering wires long enough to attach to the ground terminals on the equipment. Then I twist the bare (solid) ground wires together and crimp them back far enough that the remaining wires extending past the crimp can easily attach to the ground terminals. This is the cleanest way I have found to wire the equipment grounds, and has the advantage of providing an unbroken wire all the way back to previous box.

 

[RaysnCayne]

Wow, I had no idea this little question would generate so much debate. I've been unable to get back to the box since I asked the question, but I'll get to it tonight and post a pic of what I did. (It's a tiny bit more complicated than what I originally described.)

FYI: it's #14 wire, not 12. Didn't see any need to run 12 on light circuits. So that will help me a bit.

 

[Charles (in GA)]

In a large box with lots of circuits and lots of grounds, makes you wonder if drilling and tapping a couple of holes inside the back of the box and mounting a ground bar would be a good thing. Would eliminate a bunch of wire nuts and bulky twisted wire terminations or crimps.

Charles

 

[RaysnCayne]

Here it be gentlemen.

It's certainly amateur hour in there as I'm sure I didn't come close to dressing it like a pro would, but I think she'll work just fine. Should be enough room to push the switches in without crunching anything too badly. I took the advice of leaving all the grounds long. I made the gray nut work like a "greenie" safe and sound. And I tied only the neutrals together that needed to be tied. (I REALLY should've put all those lights on one circuit!) But she should be good enough to pass rough-in now.

Thanks for all the input.