If the ball of thermostat wire and wire nuts is not the sort of splice you like to see, we are with you! In this video we cover how to make a lineman's splice / Western Union Splice / NASA splice using a soldering iron and heat shrink.
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Read all the tech tips, take the quizzes
and find our handy calculators at https://www.hvacrschool.com/
Pam Bryan with HVAC school HVAC, our school comm and HVAC school podcast, and I'm out of my house today, it's the weekend Saturday and there's nothing I'd rather be doing and shooting videos for HVAC school. As you can see, I'm all geared up. I've got my. They might puncture it on my plug shot shirt, I'm even prepped with my steel, toed slippers, one of the things that we see a lot in the trade is.
We see splices made on low voltage wiring and usually it's made with a ball of electrical tape over a bunch of wire nuts. So as an example here, let's just say say that this wire here was skinned and we needed to splice it. Well, how would we splice it well, typically in the trade they might cut it back if they can make it reach, they can't make it reach, they might cut it back and then do a ball of wire nuts and electrical tape and strap underneath the suction line Or nobody can see it. Is that a big deal? Well, there are some better options of how this can be done and I'm going to jump right to the best option, enter fire or otherwise known as the lineman splice or the Western Union splice.
So we got ourselves the thermostat wire right and you're. Looking here, you're doing your maintenance, you're doing your service call and well, let's say: let's say: you've got a system and you get a low-voltage short-circuit. So everything looks okay, it's and all of a sudden. You come across a little spot and it's like what skint right there here's my short, so you need to go ahead and get this out of there.
But how do you do it well, like I said, the typical way would be to make a big ball of wire and wrap it with some 3m tape if you're lucky, but I'm going to show you a better way. The first step just cut this out when you're stripping back thermostat wire. This is just typical, 18:8 South wires number set wire and when you're stripping it back. I want you to snip into the end with the wire pull it back and then grab the strings.
This is a nice little string here. I've got no fingernails, but all right, so we're going to we're going to pull it back. We're going to we're going to give ourselves a little room to work here, because you need a little room to work when you do this better place. Now we're going to cut this casing and then I also cut the ends off where I snipped in, because when I snipped in it's possible that I Nick one of these wires, I'm going to cut all those ends off.
So now I've got nice. Nice wire ends to work with. One thing you want to know is: is that whenever you make a slice, you want to splice every single wire, even the wires that you don't think you're going to use is later on. Someone may need those conductors if you didn't slice them, not good.
I'm going to be cutting this in half then don't need the whole length venture it's over. So now we're going to do is solder. It alright. So we've got our letter connection here.
You can see. It's not coming apart, I'm really strong. So that's a lot of force. My cameraman is laughing at me, so you can see this fits over just nice and snug. So when I heat that up that will fit, I've already run it over the wire one of the most common mistakes you can make is forgetting to run this over the wire first and now we're ready almost ready to solder it, except there's two things I forgot. I forget glove fit other glow, offense high-power super inexpensive, weller soldering iron, ready to rake the heats being applied to the bottom of the copper. It's going to take it a little bit to heat up very soon. They see it's certain to slow and you want to get it in all of the all the connection points.
Now you want to grow it. You want to put this in your mouth immediately in order to cool it. Just kidding. Don't do that because it will hurt your mouth.
You do that. Let's talk about some length, you need to have at least about six, probably more, like eight inches, for this to be a practical splice to make, because you have the actual splice itself. But then you have to run heat shrink down the wires, and so one of the first things that I want you to do is take, and I have tried out all these different sizes. But I would take a piece of quarter-inch and run it down the wire and then run a piece of 3/8.
Over top of that just run it well down the wire, so it's out of the way and then do that on both sides. So now I've got that well out of the way in both directions in order to make this work and the reason why I did that is so that way, this can cover what I need to make up where extra back the outer sheeting and then this will Actually cover the splice, so it'll be something like that will be how to how the end configuration is with the splice being under here, and then these two kind of overlapping each other, and then this just sort of covering where extra back and then that gives me Plenty of room for me to work when I'm stripping back and then, when you strip your wires back, then put the heat shrink on them as well mmm how many times a night there's a couple easy things to forget. One of them is to run this down. The wire - and the other thing is, is that when you are finally soldering, you want to keep this as far away from where your soldering as possible, otherwise this will start to shrink down from the heat.
So I look at about my overlap point to be about 3/8 of an inch, something like that and then twist them around each other. Once you get your first full twist, then you give it a little snug to kind of a little tug to pull them together and you keep twisting around clear, so your thumbs give outline I'm actually the some wrestling champion in Florida. So my thumb's are extremely strong. You may find that your thumbs, don't hold up as well as mine.
Do should be understandable. Of course you want to make sure that you don't have any points that are protruding they're going to that are going to poke through the heat shrink when you run it over. So that's my first one. You can see it's nice and snug all right. That's one down now I just got to do all the rest of them all right now, before I start heating, all the heat shrink, I need to make sure that there's no bare wire, otherwise I'm going to be creating a short instead of preventing one. So I got to make sure if I don't see any bare wires now already does go ahead and heat shrink. This wire would literally break in half before these connections broke, but now we got to actually heat shrink them up. So that way, they're all together and looking me alright.
So now we are ready heat shrink, I'm going to suggest using half inch and set up for a 3/8 is a little little too snug. But when it's all said and done, that is a really good place. I mean it's not going anywhere, it's a great splice, but it's really a pain to make and not because any single step is really that hard. But because there's just a lot of things that you have to do in sequence and lengths makes a really big deal.
You know like when you're making a big bowl of wire nuts, it doesn't matter if you get your wire lengths all the same size, but when you're making this splice you've got to have all everything's got to line up in order for it to lay flat and We're going to get to shrink, wrap over it and even in this one I didn't quite perfectly nail it even just doing it on a table. So is there a practical use, so I guess the question on the table is: is there a practical use for this splice and I would say the answer is definitely yes, if you're left in a situation where you have no choice but make an underground low voltage, Splice we're rerunning, a wire is just totally impractical, then I think this would be the way to go if it's going to be exposed underground, exterior or something of that nature. This is going to be a really really good. Splice, it's going to be nice and tight.
It's not going to corrode over time it's going to do a really good job of preventing future short circuits or other issues. It also can bear a lot of tension on it. The wire is going to break before the splice breaks so when in comparison to wire nuts, I don't care. If it takes you, you know five times as long.
This is better, but there are some other decent options. There are the the little button connectors that people on the phone industry use where you put the two wires in and you clip them together and they have a little gel in there. Those are probably okay and in some cases they still don't look very nice and then the other option is you could use button, connector, connectors and still and still use the still use the heat shrink on it. The issue with blood end connectors is the size of the connection is going to be slightly larger because of because of that, and you need to make sure that you double the wire over when you have really small gauge hard single strand wire, like you like, we Have an 18 gauge thermostat wire in most cases and then just make sure that it's a really nice tight, snug crimp once you make that crimp connection, so that's that's also an option. Probably, the best option, like I said, is to either rerun the wire or to use a box. So if you have a an outside application, where a wire has been skinned and you can mount a weatherproof box - put some grommets and make your connections inside that box - that's probably your best bet, but this is also an option anytime you're in an environment where it's Absolutely mission-critical that you get a great connection. This is a really good option to solder connection, it's better than any pretty much any mechanical connection that you're going to make like little wire nut or with a any type of you get add some with allen. Key to tighten down on the wire for our ground, splice kits whatever this nice, this solder connection is going to be great, never use the Western Union South's price splice without soldering it because over time, they'll work apart and then that's just not a good connection.
So, if you're watching this, don't get the idea that I'm ever saying it's okay, just to twist wires together, wrap it with electrical tape and be done - that's not even close to what we did here today. This is a this is mechanically connected by twisting them together. Then soldered, then heat shrink several layers to ensure that we're not going to have any issues with this. So hopefully that was helpful to you.
I think there'll be some cases that you find that just might make sense to use this connection. I've been Brian with HVAC school HVAC, our school comm and HVAC school podcast have a great day.
You must charge an additional $175 to reconnect a shorted low voltage wire. SMH!!! I can't imagine trying to do something like that in a crawl space or attic. Lol!
Don't forget knee pads elbow pads and helmet.
lol "put this in your mouth immediately in order to cool it" Are you in Kanata ?
The best soldering gun you can get your hands on is a Weller GT7A Gun with a 120V, 150W, 700°F Power Head. It's temperature controlled so you can just keep the trigger pulled while you are soldering and it weighs less than a pound. Once you use one of these you will never go back to one of those 10 pound burners your grandfather used. They are a little hard to find but the best place to find one that I have found is eBay.
I never felt my splices were good enough, now I understand I have not been cuing the happy music while working. Thanks. Also nice explanation.
This was a good explanation of a Western Union splice. This is impractical for field work. I use butt connectors and shrink wrap. I then zip tie the cable to the suction line, snugly, on both sides of the splice. I've never had one pull apart. If anyone wants to insist on doing this in the field, Amazon carries butane soldering irons. They are super convenient.
The time it takes to splice and solder each wire. I would have already ran new thermostat wire, I wouldn't recommend this, unless it's the last job on your schedule and you want to milk the clock or something Service area Nepean??
..or you can use the heat shrink insulated crimps because in an appliance there’s no spare 8 inches of wire. Or a decent amount of space to fit a soldering iron. But I get it.
Apparently time is not money in your neck of the woods.
In the real world this place is never going to happen people don't want to pay as it is the other way seems to work and it's cheap and people like that if I did that my boss would fire me takes too much time unless we're getting paid by the hour laugh out loud
Have never seen that done with t stat wire but I like it it’s a more professional looking connection
I wanna carry this stuff so i can charge customers for "optimized splice" lol
Great idea, but ain't nobody got time for that!
Maybe on my own home.
How well does this work for communicating systems that use DC voltage?
Thank you for the video. Why is it necessary to solder the wires? Wouldn’t twisting and heat shrink be sufficient.
I learned this splice in HS shop class back in the 50s. It was used for home electrical wiring before roamex. We didn't have shrink tubing though, just old cloth electrical tape.
Use end butts
They teaches that an electrical school that's nothing new but you don't need to solder a you Service area Orleans??
Give me some blue wire nuts and no tape and I'll get the job done lol .
Incredibly professional way to repair wires. Time consuming but the right way to do it.
NASA HUMPH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I may just be studying this trade, but both of my parents were Western Union, & my dad was in Signal Corps in Army during Korean Conflict. then WU for 33 years until his death in the 1980's my mom was WU until I was born in the late 60's, WU invented it around 100 years before NASA, which was started in 1958, WU was 1851.
I actually been doing WU connections since I was a kid in single digits, & solder it, thats the way my parents insisted.
next if you have the room, you did it wrong! I just saw your typed comment on expert level of splicing like this, splice 1 wire every 2" if possible so you do not have a big pregnant section of wire, & I know, not always possible, but looks so much more professional. did that many times putting taller bars on motorcycles, many times adding 12" or more to wiring for ape hangers.
also those gloves are bad. let a drop of solder hit & melt through the cloth section, I had spark from welding just tacking melt right through a few years ago. but otherwise great video, & I had to give you a little Hell over the WU since I was raised in the old days and saw & was around old machines.
I use staggered small blue wire nuts turned up, and pull the whole length of wire including the splice through 1/2" LFNC which is how it should've been installed in the first place. One stipulation – the conduit must be configured so it can drain.
How about wire ties and liquid tape inside each tie.
Looks good. But not feasible in reality.
I think we should just use double insulated control wiring to make it less likely to need splicing
NOT happening in the real world Are you in Nepean ?
Underground and exposed? May not meet NEC code.
Flux can work magic!
If Zach doesn’t do it I’m not doing it.
Foam insulation wrap painted white on the return?
I kept one good roll of aluminum HAVC tape from my 3 years at a shop and nothing else is as strong for many DIY that I have to do to survive; I forgot what the low-pressure return is called on the condenser but aluminum HAVC tape should not only last longer but provide shielding from a few common vermin;
Nothing makes my wallet smile more than a call where the home owner wrapped his wires around the head of his weed eater. I now place all low voltage wire inside a piece of 3/8 copper pipe. Never to need splicing again. Why is this a hard concept for companies?
Yes. It did hurt.
Nice. I use this splice before, but even don`t know IT`S THE NASA SPLICE ))))
(realy wery strong and good splice)
Just turned a 2min job to a 2hr job 😳
NOPE !!!
What’s that a $300 splice?
Not supposed to use crimp connectors on solid wires
I can run a whole new wire in this amount of time. Service area Ottawa??
After hourly wage and materials it would've been cheaper to run a whole new wire…also, if it was of any importance, ex: used for an inverter or as a communication cable it would be run in a conduit or would have to run a waterproof insulated cable. Especially if it goes underground.
NASA spec is 5 turns each side for a Western Union splice, and splices are to be staggered, to minimize overall thickness of the harness. Are you in Barrhaven ?
I'm sorry but I would use a jelly crimps and ran 2 more calls that day. I would have a much better waterproof connection.
To the folks who say "it takes too long" to do this type of splice –
It *doesn't take too long*. This is the appropriate splice to use OUTSIDE or any WET LOCATION. the heat shrink tubing isn't necessary in an attic, this splice can be done with electrical tape indoors. I have used this splice literally thousands of times and it can be done MUCH faster. The point is that this repair will take about 15 minutes for a skilled journeyman to do. Assuming the customer hit the t-stat cable with a string trimmer (a relatively common problem), a competant service technician will spend about a half hour onsite to troubleshoot, repair, and test this problem using a good butane soldering iron (I use the Master Appliance Ultra-Torch UT100SI) and being mentally organized for the task. The UT100 has a hot air tip to shrink the tubing also. However, a ball of wire nuts and a wad of electrical tape will ONLY KEEP THE MOISTURE IN THE CONNECTORS. Electrical tape is the worst thing to use in a wet location! This will be ANOTHER service call, an UNHAPPY CUSTOMER, and YOU earning the label of a HACK. Good workmanship doesn't take too much time, at takes exactly the right amount of time, so use the appropriate type of connection for the application!
In an attic, a splice can be done with wire nuts, B-caps, Bean crimps, UR connectors (up to 19 AWG) and a host of other methods, including soldering. Soldering is the most secure, permanent connection you can make. Period.
Take pride in your work please, it costs about 10 times more money to send a service technician out to fix your crappy work than it does for you to do it right in the first place so please take pride in good craftsmanship, it's cheaper I. the long run Service area Kanata??
Do spliced wiring in Attic on furnace need to be in a junction box?
If you want to splice the wires with 24 v power alive cut one wire each time. Otherwise, turn off power to 24-volt control transformer before you cut cable all at once you will burnout fuse or transformer.
How dare you claim to be the thumb wrestling champion of Florida! Like you could beat me and take my title with those puny little girl thumbs. Anytime you wanna challenge the Champ just pack some fresh panties and journey up to the Panhandle. I will be more than happy to unleash the Gorilla Thumbs on you. That being said, except for the blatant lie about being the Thumb Wrestling Champion of Florida it was a good video.
Heat shrink butt connectors, they are used for underwater well pump motors at line voltage, so they would be good enough for stat wire. The marine type are best as the also have glue, and can be had in very small sizes
Holly hell that is some extreme half-hot work. Lol I like it though cant wait to see an apprentice get caught spending all day trying it🤣
Nice video. I definitely learned something new. How ever I will never be busting out eye protection much less a soldering iron with a full work load in the dead of summer laid across ceiling joists where the roof meets the wall in the attic to make a low voltage splice. It just ain't happening. Are you in Ottawa ?