Why should wires not be twisted before putting in wire nut?

Submitted by dhekurbaba t3_11x1rl7 in DIY

Hi all, a novice here, hoping for some insight.

I am replacing a flip switch with a dimmer switch in the house, and in the switch's instructions, it said to hold the wires in parallel and put in the wire nut, but not twist.

The wires I am connecting to are thick & rigid and I couldn't connect them with the switch's wires solidly enough with the nut unless I twisted them together first, so I am worried about what can happen if I go ahead and twist anyway.

Please advise, thanks!

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Sevulturus t1_jd0vzk8 wrote

Some people over twist them and they break. Especially non stranded.

As an electrician, I always twist them together first and use the nut to secure them.

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dhekurbaba OP t1_jd0wwsz wrote

i twisted, put the nut tightly and then slight tug to test

the wall wires are solid and the switch's wires are - i believe the right term is - stranded, hopefully with the tug test i'm ensuring a secure connection

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PlatypusTrapper t1_jd2e6eg wrote

It is very difficult to join stranded and solid wires in a wire nut. What often happens is that the solid wire doesn’t really get twisted and the stranded one kinda wraps around the solid one.

Ever since I’ve learned about Wago 221 wire lever nuts I’ve been using them everywhere. Much easier to use as an amateur and can easily join stranded to solid. You can even join up to 5 wires together which is something that I believe even professional electricians struggle with.

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tsunamisurfer t1_jd3mn94 wrote

As someone who just rewired and added lights to a bedroom, I cannot recommend the Wago wire nuts enough. Makes everything so much simpler. I even put them in the outlets because it makes it way easier to disconnect an outlet if you have a "pigtail" from the wago nut to the outlet - if you need to disconnect the outlet, just unlock from the Wago, no need to untwist the wire from the screw on the outlet!

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YurAvgDroidGuy t1_jd549nk wrote

And then back stab your receptacles from your wagos. That's easy fire recipe, no matches required! 🤣

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tsunamisurfer t1_jd56c5x wrote

I don't get it, is this a fire hazard or something?

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Sevulturus t1_jd5bhbt wrote

Backstabs definitely are. Not all "wagos" are created equal. So you need to be careful with them.

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tsunamisurfer t1_jd5patj wrote

I mentioned specifically that it was convenient when you don’t backstab ( I assume that is when you don’t wind it around the nut?).

What kind of wagons are a hazard? I’ve seen electricians who recommend them

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Sevulturus t1_jd5w673 wrote

I don't trust the non-levered ones that come with cheap fixtures specifically. Overall, I don't like them on anything that moves. I hate backstabs as a rule, or anything that relies on spring pressure to hold.

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tsunamisurfer t1_jd660zp wrote

Oh for sure. I didn't realize Wago sold the backstab-type wire nuts. I agree the backstab type are less stable. My recessed lights came with one of those cheap backstab nuts and it definitely didn't hold the wire as well. I've pulled quite hard on a levered wire nut and it didn't budge, so i feel pretty good about those ones.

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Wellcraft19 t1_jd5e2t9 wrote

Backstabbing outlets should be banned. I wonder how that ever passed through NFPA. They seem to work OK for some 10 years, then slowly start to weaken, creating endless problems.

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Wellcraft19 t1_jd5ebb6 wrote

Backstabbing outlets should be banned. I wonder how that ever passed through NFPA. They seem to work OK for some 10 years, then slowly start to weaken, creating endless problems. I do understand it’s much faster for an electrician to backstab over using the screw terminals, but ‘fast’ should not be the operative word when it comes to electrical installations. Quality and safety should be.

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Bun_Bun_in_heaven t1_jd63k5l wrote

Can you please explain what backstabbing is?

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YurAvgDroidGuy t1_jd64q1f wrote

Pushing a 14awg wire into a small hole in the back of a receptacle. Continuity is maintained essentially via a spring clip, rather than bending the wire around the terminal screw which is the correct method. While somehow this system passes ul certification, it is not a good idea for many reasons, and should not be considered a permanent installation. Just like wagos. Wagos are great in a pinch, but not a substitute for a permanent connection, if you were to ask most certificated electricians.

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Bun_Bun_in_heaven t1_jd65e1o wrote

That scares me now. I changed several lights in our house and installed 7 dimmers mostly using the Wagos. I cut and stripped the wires cleanly, made sure the wires were all the way in the Wagos and that the Wagos were closed. What are your thoughts, is it safe?

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PlatypusTrapper t1_jd9gqef wrote

> if you were to ask most certified electricians in the United States *

Europe has adopted these en masse.

I personally think it’s just a culture thing. Like plumbers that won’t use PEX or manifolds. Or mechanics that don’t want to work on electric cars. Tradesmen in general don’t like changing their methods as technology advances. Probably because they’re afraid of something breaking and then getting blamed for it down the road.

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LilyWhitesN17 t1_jd3ch5w wrote

When it was solid and stranded mixed, would always loose twist the solid wires, wind in the stranded and have it longer than the solid pair...when finishing the twist it tightens up holding the stranded. Single solid...and single stranded, ugh..

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nullpotato t1_jd45f1c wrote

For DIY there is nothing better than Wago. I love them for semi-permanent stuff. Understand why pros might not want to spend several dollars per box on connectors but for small projects they are amazing.

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PlatypusTrapper t1_jd47naw wrote

Why not for permanent installs? Too expensive?

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nullpotato t1_jd4bca6 wrote

Cost. I personally use them everywhere but that's because I hate wire nuts.

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YurAvgDroidGuy t1_jd7b3wp wrote

A large pack of wagos on Amazon from a container ship from who knows where may not have any certification. If you use wagos, I'd want them to be UL certified, a quality brand. I've seen some that are a stab type, some that have a lock down bar. The stab/push in type is just like back stabbing a receptacle. The lock down bar type seem to be better but pre-twisting wires and then locking down with a new wire nut is still the best way to maintain continuity and prevent a loss in amperage. If you connect a 12awg to a push in wago and have another 12awg wire continuing to a load, you may as well just use a 16awg wire to send to the load because that push in wago only has partial connection with the line. Think of it like this. Take a stranded wire and cut half the wires off on the stranded end and then twist it together with another stranded wire that has not been cut. The uncut wire will send the line power to the thinner cut wire and have a loss of power sending through the thinner wire. This is the issue with wagos, along with concerns over wires coming loose, wago falling apart, longevity, etc.

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PlatypusTrapper t1_jd7ot1b wrote

You’re right that there’s some crap that’s sold on Amazon. If it’s too cheap it’s probably crap.

The push in ones are used by some people but the internet almost exclusively recommends 221s (lever nuts).

The NEC is 99% about safety. Lever nuts have been determined to be safe.

A smaller connection at a specific point will increase the resistance a bit, that’s true. The difference is marginal though. It may get a bit hotter at the connection but that’s not nearly the same thing as getting hot along the entire cable run. The 12AWG cable will still be capable of transmitting 20A safely along the entire run.

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YurAvgDroidGuy t1_jd7zbu4 wrote

Good info. In the automobile industry, some of these computer modules are throwing codes for slight changes in resistance, for a frayed wire, or 1 strand in a bundle coming loose, very very sensitive. Obviously lights and small electronics are not likely to cause an issue in a home, where loads are not resistance sensitive, but if you have small resistance changes all over your home, and throw a toaster into the mix, a washing machine, a space heater, and these small changes in resistance in my opinion, just are not worth the risk of something happening one day.

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PlatypusTrapper t1_jd82021 wrote

Automotive wiring and building wiring is totally different 🤣🤣

You’re not going to use wire nuts in your car, right?

Building wiring is 90VAC-240VAC. By definition it has a huge range. Automotive wiring is typically 10.5VDC-15VDC (for cars anyway). Of course it’s more susceptible to resistance.

And as for safety, I watched a video where a WAGO 221 survived 100A. It only started failed at 120A and even then it was the plastic housing that melted, the connection was still fine.

I’m personally of the opinion that wire nuts are just as safe or unsafe. Even when they’re properly terminated they can still fail. This is doubly true when they’re used to terminate more than 2 wires or when they are used to terminate stranded to solid. I have personally removed 2-3 of these where one of the wires just fell right out of the wire nut 😂😂

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SangeliaKath t1_jd56akn wrote

>Those won't work in a factory setting. Where the idea is to make as many electrical items as possible. Be they beer signs, or even toys. They are not suitable for assembly type connection work.
>
>I spent nearly 20 years working in a factory that made fancy lamps aka beer signs. And I spent 95% of that time working in the wire connection sections of the lines.

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PlatypusTrapper t1_jd57sky wrote

Sure, every cent is important in such a setting so it makes sense to not use them.

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SangeliaKath t1_jde7bsf wrote

Not only is every cent they can save. But also the speed of how and what can be used.

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MosesZD t1_jd49he3 wrote

I just bought an assortment pack of them. I have to rewire some parts of the house this spring and add some new lights and ceiling fans I am so tired of twist couplers...

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Undercover_in_SF t1_jd5htuy wrote

Thanks for this! I have a house with old solid wires and had resigned myself to calling an electrician because I didn’t want to buy a soldering gun.

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PlatypusTrapper t1_jd5k78n wrote

A soldering gun? What would you want to solder?

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Undercover_in_SF t1_jd5qyad wrote

Can’t find it at the moment, but I definitely ended up on a few “how to” pages that recommended solder the two together then wire nut over the bond to make sure the stranded didn’t pull free. I obviously didn’t do much further research, or I would have run into wago’s!

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PlatypusTrapper t1_jd6a0b6 wrote

Soldering is a great way to make an electrical connection but unfortunately it doesn't make a good mechanical one. This is why you shouldn't twist wires together in-line. You should twist them together and then fold the twist over. Much more mechanically strong even if it doesn't look as pretty.

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Bun_Bun_in_heaven t1_jd63dbe wrote

Yes! Wago is amazing! Question: if I have two wires to join but the only Wagos left are three-slot (or three wires to join and what’s left is a four-slot), is it ok to leave one slot empty but closed?

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PlatypusTrapper t1_jd69s3i wrote

Yeah, that's fine. Wago's only come in 2, 3, and 5 position versions btw.

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Bun_Bun_in_heaven t1_jd6r458 wrote

Thank you! I used all 2’s and have larger ones left but didn’t remember there wasn’t a 4 :)

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Bun_Bun_in_heaven t1_jd6ref8 wrote

What are your thoughts on backstabbing with Wagos? Should this be a concern for small boxes? I replaced a bunch of dimmers and at times I had to place the wires inside tightly. All are wrapped with electrical wire.

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PlatypusTrapper t1_jd7knr8 wrote

I’m not an electrician so I really can’t say with full confidence.

I’m not sure what the backstabbing comment has to do with the WAGOs. The ones usually recommended by the internet are the 221s which are never nuts. No backstabbing with those. Are you referring to specific receptacles? I don’t backstab with those either. I’ll side wire or J-hook then if side wiring isn’t available.

I’ve seen some videos of people satisfied with products like the WAGO 773 but I don’t have experience with them.

I don’t think there’s an issue if wires are snug. As long as they fit in the box it should be fine.

The purpose of electrical tape is basically done insurance to make sure nothing touches the wires accidentally. It does basically nothing for mechanical support.

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schmag t1_jd32vah wrote

really a stranded to solid splice shouldn't be nutted... it is allowed, but like you said is difficult to get a good solid connection.

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salmiakki1 t1_jd2g2cp wrote

Is it bad to put electric tape over the nut and wires?

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Sevulturus t1_jd2r0e6 wrote

I hate it. But, where I work it is very very very hot. So if it is fresh tspe, it gets very sticky and tough to remove. If it's old it becomes dry and brittle. Either wY it is a pain in the ass to remove. And because I'm maintenance, sometimes I am trying to pull a marrette off while it is hot to check for power, and having to deal with tape while doing that is such a hassle.

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Zombie_John_Strachan t1_jd2k2aq wrote

Not bad, not required by code

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toalv t1_jd2xza2 wrote

Can be bad. A poor nut connection could be held together by the tape.

No actual electrician I know of uses tape, and in fact they use it as a tell if work has been done DIY or licensed a lot of the time.

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Odd-Cartoonist-288 t1_jd3calm wrote

Everywhere I've gone they have used tape (industrial). I've even gotten bitched at for not using it.

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Sevulturus t1_jd5cooq wrote

I find where I work it's about 50/50 and I hate the guys that tape their connections.

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danauns t1_jd2n4f3 wrote

Is bad.

If a wire comes loose, how do you troubleshoot? It's also extra volume in the box, unnecessary.

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ffxivthrowaway03 t1_jd2x0vh wrote

You... remove the tape? Electrical tape is like the easiest thing to take off in the world.

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Sluisifer t1_jd4dodb wrote

You should strip the wires such that the nut has good overlap with the insulation, and no tape is needed.

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bradorsomething t1_jd1cp9r wrote

Really? I trim and line them up, then use the twist from the wire nut to bind them and start twisting.

Is that the standard in your area? I see how it insures nothing slips down as you twist, but I feel it would take some time (not that I’m knocking it).

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Sevulturus t1_jd1khow wrote

I'm industrial maintenance. A couple extra seconds is worth not having to come back. Especially in super high vibration areas.

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tired_and_fed_up t1_jd1d1lj wrote

Wago, never deal with a nut again.

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FlatterFlat t1_jd28rx8 wrote

Wire nuts are virtually unknown in Europe, we mainly used the screw terminals historically but last few decades Wagos are taking over, especially in the DIY segment in Northern Europe.

Wago 221s for life.

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Wellcraft19 t1_jd5f60p wrote

Wire nuts are very common - on stranded wires - in Northern Europe (Sweden). Every house I’ve seen has them in the junction boxes. That said, screw terminals (‘sugar cubes’) have a place as well. But they are not better than wire nuts properly applied.

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ledow t1_jd5gdok wrote

UK - never seen one.

Never saw one in Italy, either.

I can't even imagine why you'd want to use them, to be honest. They're fiddly as hell.

And as others have echoed: Wago nowadays. Every electrician I know has gone for just having a box of Wagos and the last two I asked (who were working on large installs for workplaces) didn't even carry screw terminal blocks with them any more.

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Wellcraft19 t1_jd5gyux wrote

Maybe because properly applied, few connections are as electrically solid as when using wire nuts. But they sure are used more here in the US - where electrical standards are about a century behind Northern Europe.

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ledow t1_jd5isi4 wrote

"Wire nuts are not used in the UK because the old ceramic ones were banned many years ago for good reason"

I don't think they're any more solid, and there's a lot of talk that they weaken the connections over time / repeated use.

I've lived in houses (and worked in workplaces) with 40's and 50's wiring (and a couple of workplaces with literal 100-year-old wiring still in place, but unused) and things never came loose, just the opposite.

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party_benson t1_jd28yhn wrote

I've used these before and really like them. I've had people express their disdain over me using them though but no real idea why.

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algy888 t1_jd29o05 wrote

Wagos are awesome for things like lighting ballasts. Buy I still prefer wirenuts for anything that has a higher loads or might get hot. If it could get really hot then I use the black Bakelite ones for higher temperatures.

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MicrosoftSucks t1_jd1v6wj wrote

These are a godsend. No more bleeding hands cutting myself on wires.

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Axentor t1_jd3fmha wrote

I use these to test my 1lb antweight bit builds. So damn handy.

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ResponsibleShampoo t1_jd16jrm wrote

14 gauge wires will twist with the wire nut, any thing bigger should be twisted with lineman pliers before capping with a wire nut.

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jackson71 t1_jd13kbg wrote

Electrician here. Here are a few examples directly from the manufactures:

https://www.idealind.com/content/dam/electrical/assets/WireTermination/WireConnectors/TwistOn/Twister/Twister%20WireConnector%20Instructions.pdf

​

https://www.idealind.com/content/dam/electrical/assets/WireTermination/WireConnectors/TwistOn/WingNut/WingNut%20WireConnector%20Instructions.pdf

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JonJackjon t1_jd4du53 wrote

So "Ideal" says pretwisting is acceptable but infers it is not the preferred method.

I've always made the stranded slightly longer than the solid and have had no issues. However in my installations, the stranded is always smaller than the solid (think residential lighting fixtures).

I think the issue with twisting is some folks can make too many "twists" making the wire stressed beyond what it can safely take.

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rgraham888 t1_jd12ayh wrote

I got tired of messing with the wire nuts, so I just use push-in connectors now.

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Obstreperous_Drum t1_jd1fjak wrote

As somebody else said, 14 will usually twist well enough on its own. Anything larger and you new should twist with lineman’s beforehand.

Electrical connection rely on a mechanical connection. Wire nuts are great at holding a mechanical connection in place but not great at being the mechanical connection. The twist is necessary for longevity of the splice.

This is all in regards to solid wire. Stranded will twist on its own typically.

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dadarkgtprince t1_jd0vy57 wrote

Wire nuts were "designed" to not need to twist the solid copper, but you get a better fit by twisting them first. Nothing will happen with you twisting them first. Just twist it until it stops, and if you want you can wrap it with electrical tape

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dhekurbaba OP t1_jd0x14c wrote

i twisted, put the nut tightly and then slight tug to test

the wall wires are solid and the switch's wires are - i believe the right term is - stranded, hopefully with the tug test i'm ensuring a secure connection

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dadarkgtprince t1_jd0xty5 wrote

Yea, test tug should be good. I always do the tug and wrap with electrical tape just in case. No movement happens once you've tucked everything in already, so it should be good pending the nut stayed on when you pushed the wires back in

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dhekurbaba OP t1_jd0zc7z wrote

right, thanks for the tips

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dadarkgtprince t1_jd0zkic wrote

O, and to confirm your verbiage earlier, yes stranded is correct. Solid (where its one giant wire) or stranded (where is a lot of small wires) is how wires come

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imnotsoho t1_jd1u61i wrote

And put them in the box with the nut on top so it can't fall off.

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Punbungler t1_jd132t8 wrote

It does the job for you. More often than not, you will twist one wire around the other, and it becomes shorter. The wires then don't have enough width to catch the threads at the end.

If that's the case and you simply have to twist the wires... just cut the tip off.

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robosmrf t1_jd29dtg wrote

I twist together with lineman's pliers (nines). Then trim the end. Twist on a wire nut and then tape with black tape. Make sure the tape is wrapped the same direction to tighten the wire nut.

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Jackoffalltrades89 t1_jd357dj wrote

The problem is that oftentimes people don’t actually twist the wires together, they wrap one around the other. This is most common in cases where the gauges are different or joined solid core to stranded, because one wire is more flexible than the other. Basically, you want to see the two wires spiraling together, like a DNA strand from a high school biology book, and not one wire spiraling around the other untwisted wire, like one wire is the red stripe on a candy cane and the other is the white core.

If you end up with the latter, the wire-nut is only gripping the outer wire and the inner core can slip free. So while the technically best scenario is to properly twist the wires together and then cap with a wire-nut, the second best option is to put both wires straight into the nut and use that to twist them together as it will have at least some purchase on both wires that way. And using the straight into wire-nut makes the same connection reliably, whereas twisting first may instead wrap one around the other, which is a distant third place in terms of connection quality.

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Raul_McCai t1_jd3c2ea wrote

stranded-to-solid is best done with a Taped WAGO, or a bus bar with crimped U or Ring connectors, or with crimped spade or barrel connectors. The idea is each type of conductor has its own fastening mechanism, since there is no good option to put them together in one fastener.

If I can't do one of the above, I prefer to solder the connection, wire nut it (or insulated crimp), tape it, and then put it in a grounded isolation box, like any metal housing.

The thing about WAGOs is that they are subject to being opened accidentally. It isn't easy, but I've had it happen to me. So I tape them.

Oh the less costly imitators of WAGO are garbage, don't buy any of them to use on your home.

https://www.youtube.com/watch?v=u9jJqSGMB5g https://www.youtube.com/watch?v=WschUxip-4w

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Present_Maximum_5548 t1_jd55vhz wrote

Save them to use on other people's homes 😆

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Raul_McCai t1_jd5ilc3 wrote

you joke. My first house was also my training ground. I learned construction plumbing, electrical, roofing, rough and finish, along with sill work in that one monstrous old Victorian with 15 foot ceilings two floors & an attick that could house a small Vietnamese village.

For the electrical I copied what I saw. most of the wiring had to be replaced as it was exposed peg and post. I put Boston loops all throughout that building.

So glad the statute of limitations has expired.

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meatmechdriver t1_jd3gf8i wrote

just use wagos and enter the 21st century

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