electrical question

[john6221]

So after reading 3 different electrical books to make sure I understood the code and good practice, I decided to tackle extending a circuit in my garage. A couple of things came up that I have questions about:

1. How in the heck do I twist 4 wires together before putting on the nut? I can get 3 wires ok, but 4 is impossible for me.

1. I read about how you should not nick or scratch the wire when stripping. But, it seems that the act of twisting them together with pliers or putting on the wire nut causes small scratches. Is that ok?

Thanks!

[BudgetSlasher]

So after reading 3 different electrical books to make sure I understood the code and good practice, I decided to tackle extending a circuit in my garage. A couple of things came up that I have questions about:

1. How in the heck do I twist 4 wires together before putting on the nut? I can get 3 wires ok, but 4 is impossible for me.

linesman pliers (https://www.amazon.com/Stanley-89-865-2-Inch-Linesman-Pliers/dp/B0007XJO7A) and a larger wire nut.

You might also be able to connect 4 hot wires at a screw clamp outlet if you'd rather do that (at least I've seen it done).

1. I read about how you should not nick or scratch the wire when stripping. But, it seems that the act of twisting them together with pliers or putting on the wire nut causes small scratches. Is that ok?

Yes you will get a few impressions from those, I think what is really of concern is is scoring around the circumference (or any other means that causes a significant weak point in the copper) of the wire at the base of the exposed wire. I have worked on a few circuits were the wrong notch was used in the wire strippers (for example: a notch meant for the smaller 14 gauge wire was used on 12 gauge wire), every time I have noticed its because twisting the wires together has causes the wire to shear at that score line.

[lthenderson]

1. How in the heck do I twist 4 wires together before putting on the nut? I can get 3 wires ok, but 4 is impossible for me.

Four takes a lot of hand strength and some skill to do with the proper sized wire nut. An alternative would be to do two wire nuts with a pigtail between them. You can also buy push in connectors instead of using wire nuts.

[Papa bear]

So after reading 3 different electrical books to make sure I understood the code and good practice, I decided to tackle extending a circuit in my garage. A couple of things came up that I have questions about:

1. How in the heck do I twist 4 wires together before putting on the nut? I can get 3 wires ok, but 4 is impossible for me.

linesman pliers (https://www.amazon.com/Stanley-89-865-2-Inch-Linesman-Pliers/dp/B0007XJO7A) and a larger wire nut.

You might also be able to connect 4 hot wires at a screw clamp outlet if you'd rather do that (at least I've seen it done).

1. I read about how you should not nick or scratch the wire when stripping. But, it seems that the act of twisting them together with pliers or putting on the wire nut causes small scratches. Is that ok?

Yes you will get a few impressions from those, I think what is really of concern is is scoring around the circumference (or any other means that causes a significant weak point in the copper) of the wire at the base of the exposed wire. I have worked on a few circuits were the wrong notch was used in the wire strippers (for example: a notch meant for the smaller 14 gauge wire was used on 12 gauge wire), every time I have noticed its because twisting the wires together has causes the wire to shear at that score line.

+1 especially for the linesman pliers.


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[paddedhat]

Two ways to get four conductors twisted tight.

First,  strip a lot more than think you need, I typically end up with roughly a 1"+  of bare copper, on a solid #12. Now you take two pairs of wires, and hold them so that they form an X. They need to be less than 90* apart, closer to 45 to 60* is better.  The  wires need to cross tight to where the insulation starts. Hold this in your non-dominant hand. Now take the lineman's in the other hand and get a good bite on the bare conductors. The tip of the pliers needs to cover where the wires cross, almost touching the insulation. Now grip the wires tight, and pull the lineman's toward you, while twisting clockwise. Make a half turn, release the pliers, get a new grip and repeat. Do this until you have a nice full twist to the end. Now cut the end off, leaving about 5/8" +/-.  Next take the lineman's and twist the end of the cut. This rounds the sharp, squared off, cut end and gives the group a bit of a "thread" to help the wire nut get started.

The second way is to "add" a wire, if you can successfully twist two or three conductors, you can leave the group slightly loose, and add another wire to the bundle. You cross the new wire so that it's parallel to the threaded group and the insulation is even, then you draw into the group by pulling and twisting it tight with the lineman's.

After a bit of practice with the first technique, you will be able to easily tackle 5-#12s as long as they are all solid wire and the same gauge. When it comes to mixing wire gauges, it's a lot tougher, and often easier to twist the same size together and add the odd one in. Solids and stranded together can really suck. If it's a single solid to a single stranded, pre-twist the stranded wire with the lineman's and twist it hard. This keeps stray stands from driving you batty while you are installing the nut.Then hold the two wires so that the stranded is about 1/8" ahead of the solid before it enters the wirenut. There is little to be gained by attempting to pre-twist this combo. together before installing the nut. If it's several solids and a stranded. Twist and prep the solids, pre-twist the stranded and then enter them into a wire nut.

As for gouging or damaging the wires, it generally isn't an issue, unless you are doing as budgetslasher describes. This is called "Ringing" and it doesn't matter if you do it by misusing a stripping tool, or skinning wires with a knife, it is a real big deal. On larger conductors, like the ones feeding the main breaker in a service, ringing can cause hot spots and fires. On smaller conductors, it can weaken them until they break at the score.

I hope this helps. It's fascinating to discover how hard it is to describe something that you can do with you hands, and not give a second thought to, then realise that putting all that in words, that you hope makes sense, is another animal entirely. Good luck.

[paddedhat]

1. How in the heck do I twist 4 wires together before putting on the nut? I can get 3 wires ok, but 4 is impossible for me.

Four takes a lot of hand strength and some skill to do with the proper sized wire nut. An alternative would be to do two wire nuts with a pigtail between them. You can also buy push in connectors instead of using wire nuts.

I have a real love/hate relationship with these things. I have used buckets of them on lightly loaded applications, overhead lighting specifically. However, they work by grabbing a very small contact area of the wire by biting into it with a small spring steel tab. When used to supply high amperage, cyclical loads, like a toaster, microwave or hair dryer, IMHO, they are a safety hazard. The connection cycles, and high amp draw, tend to cause the small contact area to heat and cool. This cycling allows the tiny spring clamp to eventually saw it's way through the conductor, leading to an open circuit (if you're lucky) or to a high resistance hot spot that becomes the source of a fire. This is why you can no longer "push wire" the backs of receptacles using #12 wire. Push wired receptacles have the small cheezy little spring connection hidden in them.

 I was doing a volunteer project a while back, when a bunch of older retired guys walked me through a house that they had wired, for a low income family. They were thrilled that they had done the whole job without a wire nut, and they must of had a few hundred bucks worth of push connectors jammed into the electrical boxes. I just wanted to puke at the sight. Hopefully, these guys aren't leaving a bunch of potential failure and fire issues for homeowners to deal with, down the road.

[john6221]

Thanks everyone for the replies.

Paddedhat, your description was perfect, thanks. I tried your first method and it worked well. The wire nuts say that no pre-twist is necessary, but a previous conversation with you informed me of the best practice.

And on a good DIY note, I was able to:
-open a junction box and figure out that both a always-on and switched circuit were spliced there
-replace the over-crowded junction box with a new one
-extend the circuit with 14/3 wire to add two new receptacles with the top outlet switched and bottom always-on

I was pretty happy, felt good about doing it all myself!

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[john6221]

One more thing: plastic drywall boxes. Now, I know that they don't make cable clamps for these boxes and that the NM is required to be stapled within 8-12'' of the box. But it sure seems that the staples don't hold nearly well enough, certainly not as well as a cable clamp would. Is that normal?

[paddedhat]

The staples are no problem. They are there to position the wire in the safe zone of the stud face, away from drywall and trim nails and screws, at least  1-1/4" back from the face of the stud. Overdriving romex staples and damaging the cable insulation is a big problem. I never drive staples to the point that they do anything but lightly touch the face of the cable jacket. If you can still slide the cable a bit, under the staple, with very minimal resistance, it's properly secured. Standard cable staples with rubber coating on the saddle are a better option, and the best ones have the plastic saddle, with two individual nails preinstalled.

Nice job on all the DIY wiring. If you don't already, I would strongly suggest that you add a "non-contact voltage tester" to your tools. This isa pen that detects voltage on the outside of a hot wire or cable. I don't start any electrical project without one clipped on to my shirt. Always test it on a known live circuit before you start using it to check your work. Good luck.

[john6221]

paddedhat-- does that mean that it's ok that the NM cable is a little more "loose" inside the plastic box when compared to using a metal box with a cable clamp?

Funny that you mention a non-contact tester. That's actually the first thing I bought when I started my project!

Also, after spending all afternoon being frustrated with my cheap-o wire stripper, I went out today and bought a nice Klein pliers. One of the things that drove me crazy was that my cheap pair wasn't sized correctly for stripping wire--I kept having to use the 18 gauge hole for stripping 14 gauge wire. Also, they weren't spring loaded, and I kept having to pry them back apart every time. The Klein pair is sized perfectly--the 14 gauge hole perfectly strips 14 gauge wire, and they are spring loaded, making it much easier to use them! And since they are the width of linesman pliers, I can use them to twist and loop as well.

[paddedhat]

Yea, plastic nail on boxes without clamps are a whole other concept. Even the larger ones with the clamps that attempt to grab the cable jacket and keep the cable from being withdrawn from the box, are typically pretty useless.  As long as you have the first staple within 8" of the box, and have a 1/4" of the cable jacket remaining inside the box, you're good to go.

 It's tough to beat Klein for electrician's hand tools. I still have my first pair of Klein lineman's from the eighties. I remember spending time at lunch breaks, as a young apprentice, breaking them in, by soaking the hinge with wd-40 and furiously working the handles back and forth to get the to operate smoothly and drop open, when you held them by one handle. Eventually the plastic grips wear, and you have to install a pair of replacement grips. That can be entertaining, since you have to fish them out of a pot of boiling water and pound them on to the pliers without burning your hands. But if you get lucky enough to not accidentally blow a hole in them by cutting a live wire, they can last a lifetime.

[lthenderson]

1. How in the heck do I twist 4 wires together before putting on the nut? I can get 3 wires ok, but 4 is impossible for me.

Four takes a lot of hand strength and some skill to do with the proper sized wire nut. An alternative would be to do two wire nuts with a pigtail between them. You can also buy push in connectors instead of using wire nuts.

I have a real love/hate relationship with these things. I have used buckets of them on lightly loaded applications, overhead lighting specifically. However, they work by grabbing a very small contact area of the wire by biting into it with a small spring steel tab. When used to supply high amperage, cyclical loads, like a toaster, microwave or hair dryer, IMHO, they are a safety hazard. The connection cycles, and high amp draw, tend to cause the small contact area to heat and cool. This cycling allows the tiny spring clamp to eventually saw it's way through the conductor, leading to an open circuit (if you're lucky) or to a high resistance hot spot that becomes the source of a fire. This is why you can no longer "push wire" the backs of receptacles using #12 wire. Push wired receptacles have the small cheezy little spring connection hidden in them.

 I was doing a volunteer project a while back, when a bunch of older retired guys walked me through a house that they had wired, for a low income family. They were thrilled that they had done the whole job without a wire nut, and they must of had a few hundred bucks worth of push connectors jammed into the electrical boxes. I just wanted to puke at the sight. Hopefully, these guys aren't leaving a bunch of potential failure and fire issues for homeowners to deal with, down the road.

I too don't like using them although I've heard others in the trade say they've gotten better over the years. I recently saw a wirenut on television that comes with a wire out the top so that it eliminates needing to add a pigtail and effectively reduces the wires nutted together by one. I wondered how well it is put together.

[paddedhat]

I doubt that tailed wirenuts are a problem. They have been available as a ground tail, with a green nut and wire, for decades.

[john6221]

Follow-up question regarding NM cable. When running it perpendicular through joists/studs, I know that I need to have 1.25 inches between the hole and the outside edge, otherwise a protective plate is required. How do I cross through a joist cavity that has an HVAC branch? Over, or under?

[lthenderson]

Follow-up question regarding NM cable. When running it perpendicular through joists/studs, I know that I need to have 1.25 inches between the hole and the outside edge, otherwise a protective plate is required. How do I cross through a joist cavity that has an HVAC branch? Over, or under?

Most codes these days say if the duct is carrying environmental air and not a duct removing fumes, dust or other particulates, you can run a wire through it but it needs to be metal sheathed. If it is the latter kind of duct, you can't go through it at all.

[paddedhat]

To follow up on Ithenderson, he is correct,  never run romex through a duct. The biggest issue tends to be ductwork that is "panned" when the entire joist bay is used as a duct, by attaching a sheet metal, or fiberglass ductboard, "pan" across the bottom of the joists, creating a four sided duct. It's generally done on return air ducts, and it's IMHO, a garbage way to do the job.  If you are working a romex around a standard round, oval, or flex duct, I always look at trying to loop over the thing, unless it pushes the wire tight to the bottom of the subfloor. Not only is it important to keep romex back from the face of the stud, but it shouldn't be tight to the subfloor either.  You would be amazed at how many flooring installers and remodelers end up shorting cables out, or puncturing water lines, by nailing through the floor. Not their fault at all, since the piping and cabling didn't belong that tight to the bottom of the subfloor in the first place.

[john6221]

Ok, sounds good. This duct isn't one of those crappy pan return ducts. It's a 4'' supply duct. I will have to see how much space is between the duct and the subfloor, but it's good to know that I have options.

[srob]

This is an interesting discussion!

A similar question, let's say that you finish a basement with 1x2 strips and rigid foam insulation, with drywall on top. Your wiring might not be set back very far behind the drywall bc there isn't much space, just an inch. Do you need to use metallic sheathed cable or conduit in this application?

Also, if you put in remodel can type recessed lighting and run new wiring through the ceiling, is it ok if it is loose/resting on the ceiling drywall?

[sokoloff]

For the walls where you're only using furring strips, I'd try to keep all the wiring down at knee level. People are very unlikely to hang pictures that low.

For the remodel recessed can case, yeah, you pretty much have to just fish and let the NM lie along the drywall ceiling. It's done all the time and there's not any other realistic option. Fortunately, there isn't much nailing of pictures up through a ceiling either, so it's fine. :)

[zolotiyeruki]

This is an interesting discussion!

A similar question, let's say that you finish a basement with 1x2 strips and rigid foam insulation, with drywall on top. Your wiring might not be set back very far behind the drywall bc there isn't much space, just an inch. Do you need to use metallic sheathed cable or conduit in this application?

Also, if you put in remodel can type recessed lighting and run new wiring through the ceiling, is it ok if it is loose/resting on the ceiling drywall?

paddedhat will probably correct me on this, but the issue is the possibility of driving a screw or nail through the romex.  That's why it's an issue where the romex passes through a stud (since a screw could be forced through).  If it's a situation where the romex can simply be pushed to one side, it's not an issue.  Just think of all those attics with romex draped across to the ceiling boxes.

[paddedhat]

Nope. you're right about the whole concept of protecting wires. when adding or repairing existing wiring, as in "fishing" romex through existing wall and ceiling cavities, you cannot be reasonably expected to fasten it in any way. The fact that it floats can be a positive, as fasteners are less likely to penetrate the wire. In attics it's all about uninhabitable space VS. accessibility. If you install a permanent ladder or steps to the space, then all romex needs to be installed like any other area of the home. The exception being that you can attach cable across the tops of joists and protect the wire with furring strips nailed adjacent to each side of the wire.

Remember that you not only want to keep holes in studs an inch and a quarter back from the edge, but you need to watch as you attach wires to the sides of studs and keep them back from the edge as well. I once laughed as another local  builder had to pull a huge area of a kitchen apart in a new home. The "electrician" had run a bundle of wires down the wall, and managed to secure them flush with the inside face of the stud. The "professional drywaller"then managed to screw the wire bundle tight to the back of the sheetrock, not once, but several times. Since the place was all cathedral ceilings, there was no place to hide junction boxes to patch wires, so the cure was to do a lot of ripping and tearing, while running replacement cables.  It's rare to see such a convergence of morons, but sometimes you get lucky, and the planets align. LOL.

[zolotiyeruki]

Nope. you're right about the whole concept of protecting wires. when adding or repairing existing wiring, as in "fishing" romex through existing wall and ceiling cavities, you cannot be reasonably expected to fasten it in any way. The fact that it floats can be a positive, as fasteners are less likely to penetrate the wire. In attics it's all about uninhabitable space VS. accessibility. If you install a permanent ladder or steps to the space, then all romex needs to be installed like any other area of the home. The exception being that you can attach cable across the tops of joists and protect the wire with furring strips nailed adjacent to each side of the wire.

Remember that you not only want to keep holes in studs an inch and a quarter back from the edge, but you need to watch as you attach wires to the sides of studs and keep them back from the edge as well. I once laughed as another local  builder had to pull a huge area of a kitchen apart in a new home. The "electrician" had run a bundle of wires down the wall, and managed to secure them flush with the inside face of the stud. The "professional drywaller"then managed to screw the wire bundle tight to the back of the sheetrock, not once, but several times. Since the place was all cathedral ceilings, there was no place to hide junction boxes to patch wires, so the cure was to do a lot of ripping and tearing, while running replacement cables.  It's rare to see such a convergence of morons, but sometimes you get lucky, and the planets align. LOL.

Interesting--I was unaware of the "attic stairs => romex has to be protected" rule.  It certainly wasn't followed in my last house!

Did the drywaller think his screws were sinking into studs? Wow.