Basic Electricity For Low Voltage Installers

Due to technical difficulties we bring back a great episode with JATC instructors to make volts, amps, current, and watts feel practical for low voltage work as PoE and modern power delivery move into our lane. We trade water-pressure analogies, real safety stories, and jobsite mistakes so you can size power correctly and stop burning up gear. 
• why PoE and fault managed power make electricity fundamentals mandatory for ICT techs 
• voltage as electrical pressure between two points and why “low voltage” depends on audience 
• how voltage ratings and mixed cabling types can create code and safety issues 
• amps, current, and heat as the real-world limiters for conductors, bundles, and racks 
• AC vs DC confusion in the field and how mismatched power supplies destroy equipment 
• electrical safety explained as volts and amps combining into dangerous wattage in the body 
• watts as work, watt-hours as billing, and why PoE wattage keeps climbing 
• end-of-line voltage, resistance, and voltage drop affecting device performance 
• common low voltage mistakes with power delivery and how to avoid “letting the smoke out” 
• learning resources: All About Circuits, manufacturer PoE training, EveryCircuit, FOA and Uncle Ted’s 
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Transcript

Welcome And Why Power Matters

SPEAKER_05 0:00

Hey water monkeys, welcome to another episode of Let's Talk Cabling. This episode we're talking basic electricity.

SPEAKER_02 0:13

Yeah, let's talk cabling. Have a fiber structure to write. Some day to day and time. Stay connected.

SPEAKER_05 0:27

Do it right Welcome to the show where we tackle the tough questions submitted by apprentices, installers, technicians, project managers, estimators, even customers. We are connecting at the human level so that we can connect the world. If you're watching the show on YouTube, would you mind hitting the subscribe button and that bell button to be notified when new content is being produced? If you're listening to us on one of the audio podcast platforms, would you mind giving us a five-star rating? Those simple little steps help us take on the algorithm so we can educate, encourage, and enrich the lives of people in the ICT industry. Wednesday nights at 6 p.m. Eastern Standard Time, what are you doing? You know I do a live stream where you get to ask your favorites, RCDD, and you know that's me, your questions on installation, certification, design, project management. I even do career path questions. But I can hear you now. But Chuck, I'm dropping my truck at Wednesday nights at 6 p.m. I don't want to get into an exit. I record them and you can watch them at your convenience. And finally, while this show is free and will always remain free, if you find value in this content, will you click on that QR code right there? You can become a Patreon member, you can go to the webpage and buy stuff through the Amazon link. Or we're also looking for corporate sponsorship as well. You know, I've been an ICT technician for 40 plus years. Sometimes I think about that and I go, wow, I forget how old I am until I'm trimming up my mustache and I see all the gray in my mustache. It's like, it didn't used to be that way. I should probably throw up a picture of me like when I'm in my 20s. And I realize that one electrician, there's always that electrician versus low voltage, which is better, right? Well, there's one area where electricians are always almost better than us. And that's when you start talking about volts, current, watts. Ask a low voltage guy to explain that kind of stuff to you. Yeah, good luck with that. Unless you happen to find one who's also an electrician. So I'm dedicating today's show into

Meet The JATC Guests

SPEAKER_05 2:33

what exactly are these things. And so I got to thinking who would be the best person to bring this on the show to discuss. And of course, my dogs are barking. And of course, that had to be my good friends from the JATC in Las Vegas, right after the Bixie conference. Dang it, I wish I could have gone there. Matt Affel and Brandon Duffy. Hello, gentlemen. Welcome to the show. Morning.

SPEAKER_04 2:56

Morning, Chuck. How are you doing today?

SPEAKER_05 2:58

I am doing fantastic. Anytime I get to talk with my buddies, it's a good day. So let's go ahead and do it. Let's go ahead and do the introductions. So for the for the three people who listen to my show, and well, and since two of them are actually on the show, so the one person who watches my show, let's do an introduction. Who are you guys? And uh why why should we listen to you? We'll start off with you, Brandon.

SPEAKER_03 3:21

Well, my name's Brandon Duffy. I'm the recently meant to curriculum coordinator for the JTC of Southern Nevada. I'm a uh somewhat forcibly retired mathematician. I taught public, uh private college mathematics mainly, and uh my my scope over here is teaching uh a broad array of curriculum classes with a heavy emphasis on mathematical computation.

SPEAKER_05 3:45

Very cool. Matt?

SPEAKER_04 3:47

Well, my name is Matthew Apfell. I'm one of the assistant training directors here at the Electrical JATC of Southern Nevada. I'm a senior technician. Um here at the JATC for about uh 15 years now, and full-time as an assistant director for three years. Uh, but being a senior technician, a big CRCD technician, as well as a certified trainer, we we we deal with a lot of different aspects of the limited energy information, communications, technology industry. And one of those things that we see more and more of these days is power delivery. So that's what I'm here to talk to you about.

SPEAKER_05 4:22

Right. And you know, one of the reasons I really want to get into this stuff is it for low voltage installers, for many, many years it's it's okay to have a cursory knowledge of volts and amps and current and and watts, you know, but but now with power over Ethernet and fault managed power systems and all that other stuff being rolled into our job

Voltage Explained With Water Pressure

SPEAKER_05 4:45

description, it's even more critical that we understand this stuff. So let's let's kick this off with volts, right? Can you explain what is volts in its simplest terms, and how can you compare that to something familiar to the text in their everyday life?

SPEAKER_03 5:00

So the analogy that you you typically see in the classroom and a lot of uh t-shirts that you buy off the internet is you've got the three guys, you got one trying to push another through the tube, and uh you got another with rope stenched around the tube. And the the analogy for the volts is it's pressure. And pressure is a somewhat unit unitless uh quantity until you decide what trade you're applying to. If you're a plumber, you know it's gonna be pressure between uh two opposite ends and some kind of fighter in between. With us, it's it's the quantity that's trying to push electrons, for lack of a uh simpler phrase. It's just pressure. And uh one of the things that tied me up in my apprenticeship was it requires two locations to be able to talk about it. You need to talk about voltage from here, from point A to point B. You can't just look at an instantaneous point. It's a difference. It's it needs two quantities. Voltage is a it's an operator, it's not a specific value.

SPEAKER_05 5:58

Matt, how does uh how does voltage affect the performance of low voltage cables? And what is the and can you settle the difference? I mean, settle the argument of what is low voltage, what is high voltage? Because you hear that a lot.

SPEAKER_04 6:12

And and that's an excellent question because it depends on who you're talking to. Low voltage, if you're talking to a lineman, will typically be anything below a certain uh thousands of volts. If you're talking to uh to an electrician or a germ environment, a low voltage might be anything less than 120 volts. But if you're talking to a technician, low voltage would typically be anything below 24 to 48 volts. So it just who's your audience? And the reason why that's important these days is that because the technology, the industry is changing so much, uh, we need to really quantify and really nail that down. And uh the the difference is these days is that with cabling, when you're talking about voltage, now we're starting to see uh a mix of cabling types. We're starting to see communications cable with a certain voltage rating on its jacket being mixed in with uh power conductors that might have a different voltage rating on the jacket. So depending on no matter who you're talking to, you need to be able to identify what voltage is, what the cable type is, and make sure that if you don't have an honest understanding of what it is, that you're not committing code infractions or other violations that might get you or your contractor in trouble.

SPEAKER_01 7:26

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SPEAKER_05 8:07

So how does voltage affect the performance of a low voltage system, though?

SPEAKER_04 8:12

Okay. So if you were talking about a uh PoE system, okay, where PoE cabling is typically referred to as Watts. Well, we're gonna talk about watts here in a second, but Watts in power has an applied voltage to it. That voltage is is what is necessary along with the wattage in order for our clients and what the end product in order for it to work. Um you can also see voltage and cabling in the audio systems. You see a lot of audio systems that might be 70 or 100 volt audio systems, where if the proper voltage isn't applied through the cabling into the speaker, then you're just not going to work properly. And the installation and the understanding and how it's installed and how many speakers, um, where it's applied on the amp, all those things are super necessary these days in order for a quality install. So having the right voltage, having the right cable is very important.

SPEAKER_03 9:11

And again, voltage being the difference in pressure of an electrical nature, so to speak. You put a little rotary uh garden garden water sprinkler out there, how much of the how much of the garden do you want to hit? You know, do you want to apply 15 volts and get 200 gallons of water out there over three hours, or do you want to hit it with 100 volts, or 120 for this for this matter, and actually hit the entire garden in five minutes?

SPEAKER_05 9:36

Well, I got the I got the perfect analogy for this. So so if you if you follow me on my journey of life, you know that I'm a farmer, well, a homesteader. I call myself a farmer, but I'm really a homesteader. My wife has a butterfly garden. So anything on the property that we grow has to either attract bees, feed us, or feed the livestock on the property, right? We don't grow stuff just because it's pretty. So my wife's got a butterfly garden where it brings her joy. So she she finally talked me into doing it. So we put a butterfly garden out there. It's not that big, it's maybe, I don't know, 20 feet by 20 feet, and it's got lots of pretty flowers in it. And so we went out and bought these um waterers. They're made out of copper tubing, they come up and they had two circles. And you hook the hose at the bottom, and what happens is those circles spin and the water comes out in like a globe fashion, right? So we had one in our butterfly garden, worked fine. And then she said, Well, it's not getting water over this other area. So we went and bought a short piece of hose, attached it to that, put in the second one. Guess what? The second one wouldn't spin because there wasn't enough pressure. Volt analogy? Yes or no?

SPEAKER_03 10:47

Absolutely perfect. Yes!

SPEAKER_05 10:50

Feel free to use that in your class, just make sure you give me credit.

What Counts As Low Voltage

SPEAKER_05 10:54

Let's shift the conversation to amps. What are amps and how do they relate to the movement of electricity?

SPEAKER_03 11:02

So amps being in units of coulombs, it's amps are essentially the speed of um, I guess you would say it's the electrons moving, but but more practical in terms of more practicality, we use the forces that those moving electrons create. That ties into voltage too. But amperage is um it's it's the big problem when it comes to the rating of the conductor, uh, what you're gonna use to send amps from point A to B. That's our heat factor. That's what's gonna start causing problems. And we'll talk about watch here in a minute, but it's the amps that you rate the uh the circumference of the pipe that you're sending the water to from point A to point B.

SPEAKER_05 11:43

So if I had gone with smaller hoses on my butterfly garden waters, they might have worked. Absolutely. Well, actually, that's kind of what we did, but that's but that's beside the whole point. That's beside the point. Now, when you started your when you started your explanation off, you use a term that I never heard before, but gosh, my memory's already forgotten what it was. I'll if I can think of if I can think of it. Settle this argument for me. Okay, I'm not an electrician. I am just a low knuckle-dragging, low voltage cable guy who who doesn't know anything. So I've seen the I've seen people, I'm not people, but various sources of information when they talk about electricity. Some sources say the electrons go from one end of the cable to the other end of the cable. Other sources say that they just go back and forth. Eh, which is it?

SPEAKER_03 12:44

So uh right there is the analogy between AC and DC. And I mean, display directions are really not different. If I'm playing Mortal Kombat in America and my my teammates over in Vietnam, am I sending an electron from here to Vietnam so that the data can be transferred? And the answer is no, absolutely not. Uh without having to talk about um induction or transfer of power. What we are uh caring about is the transfer of the forces that are created by the electrons fighting each other, essentially. We we're moving voltages around, and that is caused by the change of amperage, but it's it's resulting forces and uh properties that that creates that we're interested in.

SPEAKER_05 13:30

Gotcha. Matt, when working with low voltage, what is the practical significance of amps and how does understanding amps help us from causing problems or mistakes in the field?

SPEAKER_04 13:43

Well, there's a lot of different appliances and things that we're plugging

Amps And Why Heat Happens

SPEAKER_04 13:46

in and hooking up these days. Um and those those appliances, and I'll use something like a camera, for instance. Okay, if the camera has a uh a DC uh power supply that's powering it, you need to make sure that it has the right voltage, but also the correct amperage, because if it doesn't have the proper amperage, let's say the amperage is too low, it's just not gonna work. If the amperage is too high, it might work for a second or two, but then it's gonna overpower itself and you might let the smoke out. So a too high or improper amperage can cause a heating of the conductor, it can cause problems. And the conductors or the copper, the aluminum conductors themselves are rated for the amperage that they're gonna be applying across them. And as Brandon said, it's anytime you have the transference of energy with voltage and amperage, then it creates heat. And that heat can cause a problem. And that's one of the problems that we see today in the industry a lot is is people not applying the proper power of the uh whether it be AC or DC, having too many cables bundled together, uh, appliances too close together, stacked in racks, and then you have an overheating problem and you have a breakdown, you have thermal breakdown, and you let the smoke out. So that's and that's a huge problem with uh with the delivery of current and power and average in the pro in the industry today.

SPEAKER_05 15:09

Let me let me apply this to a uh a story that I heard. I did this did not happen to me, okay? This is a story. So a long, long time ago, I had a I mean, a friend of mine had a uh a Mod Tap SLT3 tester. Now, for those who don't know what that is, it's just a simple continuity tester. It had four lights on it. You'd plug it into the cable, you had a remote, you put on the other side, and it would light up pair one, pair two, pair three, pair four, and they better be all green. If one of them turned red, you had a reversal, right? And it said on the instructions, not that anybody read the instructions, don't plug into an active circuit. What'd you do? Let's just say let's just say that somebody might have plugged it into an active circuit, and the LED light started smoking and it burnt it out. Was that because of amps? Too much amps?

SPEAKER_04 15:59

Yeah, yeah, I'd say so. Um, and um when we start talking about power here, uh, we're gonna learn that voltage and amperage have a pretty significant relationship with each other, and that voltage, when you apply more voltage, it actually affects the current. So, and it affects what you're plugging it into. So you probably had too many amps, but you also probably had too many volts, which then therefore affected your affected your but it's low voltage.

SPEAKER_05 16:31

It's low voltage, though.

SPEAKER_04 16:33

Yeah, yeah. Well, you know, it used to be that um if you were a telco technician, all you cared about was your ring voltage. All you cared about whether whether or not you had dial tone and whether or not the you know the circuit was uh was ringing and you had loop back, and then you're hopefully your hand wasn't on the 66 board when you're punching things down because you got bit.

SPEAKER_05 16:52

Yeah, yeah. For for those who don't know what ring voltage is, on the in the old days, before wireless, when everybody had landlines, um, when the they had to send voltage down the cable to ring the bell in the phone. That's what the term ring voltage comes from. And I remember we did a project at J.W. Marriott, downtown Washington, D.C. We had to tone out every single phone line in that building, all the rooms, back of house stuff. And it was so funny because the guys they would take their, they would take their probe, which I have one on my desk. Here we go. They would take their probe. Now back then we had metal tips and they would put it on the thing and they'd go down until they heard the beep, right? Well, they realized that was kind of slow. So what'd they do? They took the the probe, turned around in the back of their hand, licked their finger, and we just go down the block. 66 bucks real quick with them. And the first time they hit ring voltage was really hilarious. They went, wow! By the end of the project, they were just going, yep,

AC Vs DC And What Moves

SPEAKER_05 17:44

ring voltage. Yep, yep.

SPEAKER_00 17:46

Yep, right, yeah.

SPEAKER_05 17:48

It'll it'll wake you up, that's for sure. It'll kill you. But it'll wake you up. It'll bite you. It's better than a cup of coffee. It doesn't taste as good, but it'll wake you up. Arguable. Now let's now let's shift the current the conversation to current. Okay, Brandon, what is can you break down the concept of current and in a way that would make sense to even us low voltage people?

SPEAKER_03 18:10

So, quality aside, current is just the amount of electron flow from point A to point B. It's it's the water in the pipe. And uh when water moves in the electrician's pipe, again, we create the heat.

SPEAKER_05 18:23

Matt, you get to you get to explain current and how it affects the low voltage installed. Remember, low voltage is everything from voice data to fire alarm to gas to everything.

SPEAKER_04 18:36

Yeah, and that that that current, uh whether you're talking about the current, the transfer of electrons themselves, um it's that that that is the power. That is the water, that is the juice, that is what's making things work. So once again, today's electronics and today's appliances that we're installing in the field are very, very sensitive. They are exact. The tolerances in which that these items are manufactured are not very yielding at all. And back to the whole idea of too much or too little when it comes to current, that's the make or break. And that is what's very important about our installation these these days, because uh if you have too much resistance because your cable is junk or you have your terminations are improper, then that's gonna affect your current. That's gonna have you're not gonna have enough power um delivered to your to your product that you're installing, and then it's just not gonna work. So the current, the electrons, what kind of water you're actually getting, that's gonna that's gonna make or break your situation.

SPEAKER_03 19:47

And in terms of, like you said, the water that uh the water that we're moving, low voltage may depend, uh the definition of low voltage may depend on what trade's doing it. Uh if the the wire men are running right next to the the techs, you know, our water, our water tends to talk to each other. That's why we have a separation. Uh last I saw I was doing at a convention center, the typical uh separation between power and data would be anywhere from 10 inches to 12 inches. Or water talks.

SPEAKER_05 20:17

Yeah, it does.

Safety Debate What Actually Hurts

SPEAKER_05 20:18

Let's take a side step for a second. Let's talk about safety for just a brief second or two, right? You hear all the time, you know, take steps to protect yourself from uh from to being injured from working with electricity, even low voltage stuff. And some people will tell you it's not volts, it's the amps. It's not amps, it's the volts. Which is it that that causes problem and hurts people?

SPEAKER_03 20:42

So yeah. Um I I have the uh distinction of being popped by 880 DC, changing a fuse, as not, yeah. There's a uh unspecified year apprentice without proper supervision in a local that shall not be named. And I'll tell you um 880 volts DC will knock you unconscious. You'll wake up 10 feet away from where you were previously with your journal running over to you asking if you're alive. Um, and that's without a load. I'm alive today because there was no load on that. Now, at the same time, I've had um the privilege of holding on to a 120 core, working with dad at home with a load on it, not being able to let go of it and just watching it kill me. So um, long story short, it's the wattage created within the body that's gonna kill you. Whether Yeah, it's gonna be the wattage that kills you. Yeah.

SPEAKER_05 21:36

So that's a perfect segue, because the next kind of thing I'm gonna talk about was watts.

SPEAKER_01 21:42

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SPEAKER_05 22:54

I didn't even know that. I just, as we were talking, you were talking about volts and amperage, it hit me that, you know, you know, in the Bixie thing, it tells you, well, if you you know the heart stops beating at 250 milliamps, and I've heard other people say, no, it's not the voltage, it's the amps, and blah, blah, blah, blah, blah. So what I'm hearing from you guys is it could be both.

SPEAKER_04 23:12

It is it is both. And I'll and I'll and I'll kind of put it simply, since we're gonna kind of lead up into power and watts next, is that um here's you know, here's an item. Okay, it's not very large, it's not very heavy. Um, it it has a certain mass. So we'll say that this is a certain load or this is a certain amberage. Um if it's not moving very fast, it's not gonna hurt. Okay, if I don't have too much pressure, it's not gonna hurt. Now, if I were to stand back and to throw this at you, it's gonna hurt. Verify. So that's that's kind of the analogy of uh of which is it? Is it the volts or the amps that hurts?

SPEAKER_03 23:52

Well, if if applied together properly, it hurts. So uh I have an amazing example related to me years back. The human body is is absolutely astounding in its complexity, and we have tens, if not hundreds, of thousands of volts within our system just moving things around and electrons shooting back and forth all day. And we've we've got current moving through our body through neurons, and they're all traveling at the same point. There's there's enough amperage in there to kill you several times over, but it's not until with those powers combined in the perfect storm that you're getting enough wattage to slam you through the wall. That exists in the human body.

SPEAKER_05 24:30

Yeah. Yeah, and the human body is the majority of it's water, and there's a lot of salt in our body, and both of the salt water is conductive. Don't don't ask me how I know that. So so like I said, that was perfectly lead into watts, and that was done totally unintentionally.

Watts Work PoE And Power Scaling

SPEAKER_05 24:50

It just worked, right? Watts. Okay, Brandon, you hear a lot about watts. What exactly is a watt and how do they bring volts and amperage together?

SPEAKER_03 24:59

Okay, so mathematics aside, watts are by definition resistive voltage times resist of current. It is an instantaneous value. So there's a lot of uh confusion when it comes to my power bill. What's a watt hour? A watt is an instantaneous moment of work. Well, what is that? You can take a picture of a weightlifter, uh lifting much more than I can, take a picture of it, and it looks pretty easy. I can do that. Well, how long is he holding on to that weight? And and that's a watt hour. It's work. That's why we're billed in terms of KWS or KWH watt hours. Um one of these days I'd like to call the the electric company say, I only use about 235 watts. What's the problem?

SPEAKER_05 25:45

Matt, bring it together for us. How does how does watts affect low voltage? Especially let's talk about choosing the right tools and also PoE.

SPEAKER_04 25:54

Yeah, watts is uh watts is the rage these days. Uh you're starting to see more and more things that are expressed in watts because as we call it low voltage consumer grade appliances, cameras, access control items, PCs, monitors, all these things that people just used to plug in and just didn't even care. But the more that these things are actually powered via limited energy, either distributed DC or PoE, power for Ethernet, they have a watt value. They have a certain amount of work that is required by the circuit in order to make it work. Uh and in PoE, 20 years ago when this technology first started coming out, you know, 15 watts was common. Then it turned into 30 watts, then it turned into 60 watts, then it turned into 90 watts. And now we're seeing more than 90 watts. We're starting to see 100 watts. Well, what does that mean? Well, it just means that more and more things are able to work off of power for Ethernet. More and more technicians in the field today that are installing cable and an infrastructure for these systems, their work, their end-line product is dependent upon the wattage and the correct installation of these things. So in the industry today, an average technician, the expectations of him having to understand the infrastructure and understanding the need is becoming more and more important. Those standards that we see, the IEEE standards that define what uh what POE is, as well as other technologies such as digital electricity, which is delivering power, it's delivering uh the capability of performing work. So the average technician, the average low voltage low voltage installer these days, uh it getting this education on what that means is very, very important.

SPEAKER_05 27:48

You know, this is why I love hanging out with people that are smarter than me. I never I've known that I've known the PoE wattages for years, you know, 15, 30, 60, 90, and now 100 plus. I never paid attention to it before until you just rattled it off. Is it is it coincidental or is there a reasoning behind we doubled it? We went from 15 to 30, and then we went from 30 to 60. Is there a reason why we're doubling it, or is that just happened to be pure coincidence?

SPEAKER_04 28:16

Well, um we'll call it out of a uh it was a product of um of coincidence because you happen to have so many pairs in a uh uh twisted pair cabling. Um when you really get into the standards of PoE and what it is, then you start to see that so many of the pairs. So eight conductor, four-pair cable, so many pairs are used for power on each standard. These days we're up to four-pair PoE, which enables us to send a certain amount of power and data over each pair. Um previous standards of PoE only used either one, two, uh, or more pairs, depending on what it was and what the manufacturer was. But in a nutshell, that's kind of simplistically how you're able to multiply your power like that. Um but keep in mind that uh our industry standards these days that have done amazing things with power, with wattage, what the end-of-line voltage is, but also the data, the throughput of what the capabilities of signal transmission is all simultaneously while delivering power. It's it's an amazing thing.

SPEAKER_05 29:24

So you use the term that I've heard you use before, and I never thought about it until just

End Of Line Voltage And Voltage Drop

SPEAKER_05 29:30

now. What's the difference between end-of-line voltage and voltage?

SPEAKER_04 29:35

Well, simply put like this. So we're gonna go back to our analogy of talking about the uh uh a pipe and water, and uh, you know, we'll talk about a spigot. Okay, the longer the hose, the more resistance. Okay, therefore, the pressure that you get from the spigot or from the source is not gonna be the same exact pressure that you get at the end of the hose. Now, Chuck, when you guys were installing your water features and trying to water the uh water your crops and whatnot, uh right then before you started splitting it, before you started affecting the length of how far it had to travel, you probably had a decent amount of water pressure. But the farther you went, and the the depending on the size of the hose you had, um affected at the pressure at the end. Well, that's kind of what we see in uh communications cabling and electricity in general. Um, all media has resistance and impedance built into it. Um that's just the nature of the impurities of the manufacturing process, whether it's copper or aluminum. And uh quite simply said, is that if you have a power source that's putting out 90 volts, AC or DC, by the time that voltage and that current gets down to the end of the cable to your product, you're not gonna have 90 volts. You're gonna have so much voltage drop. And that's due to the length of the cable, the resistance of the cable. And um, those are all things that our even our technicians these days need to understand.

SPEAKER_03 31:05

When when we do lectures in class, uh we like to talk about uh, in terms of AC theory, purely inductive circuits and purely capacitive circuits, which is kind of beyond the scope of this, but they're purely theoretical. Uh, we always have to consider something called I squared R loss, and that's wattage loss doing the pre-work to do the work we want as the end result.

SPEAKER_05 31:27

Gotcha. So end-of-line voltage is basically your voltage drop between where it goes into the cable and where comes out the cable.

SPEAKER_03 31:35

Yep, sir. It takes money to spend it, it takes money to make money, it takes watts to spend watts.

SPEAKER_05 31:42

I love that. Now let's tie it all together. This is probably why you were invited to be on the show, Brandon. Let's bring it all together. What's talk talk about the relationship between volts, amps, and watts? Remember, we're talking to low voltage people here, not electricians.

SPEAKER_03 31:57

Okay, so I'm I'm gonna assume that um you guys are familiar with something called power factor. And when uh when we go through doing calculations in my classroom on the board, I'll put uh an absolutely nightmarish two and a half hour circuit on the board, and you're finding values for every single silly component there. And the only question I'm asking them to do is find the wattage for this nightmare. We'll spend two and a half hours doing it, but at the end of the day, your volt amps apparent, that is the maximum allowable energy in your circuit at any point in time. And its unit is exactly that volt amps. We don't know if they're reactive, we don't know if they're watts. But once we have that power factor, we just have a simple multiplication. We can compound our power factor with our VAs, and that tells you exactly how many watts you can expect.

SPEAKER_00 32:46

Gotcha.

SPEAKER_05 32:47

So since you're the mathematician, there's always that the the uh that diagram that talks about you know voltage and and current and all that stuff. And if you have two values, you can calculate the third. Um can you walk this through that?

SPEAKER_03 33:06

That's about a three-hour conversation.

SPEAKER_05 33:10

So that'll be on part two and part three then.

SPEAKER_03 33:13

Yes, so when you talk about AC or DC or rectified AC to get DC, you still have to uh you have some compounding problems called capacitance and inductance, and those are um a lot of the calculations that you have to lot for when you're getting your eventual VAs and then finding your power factor and your phase angle using inverse trig. Uh simply put, it is a lot of math and it's a lot of uh it's a lot of calculations on a whiteboard that you know it's it's that nightmare you got back there, and and we'll we'll save that for possibly a later time.

SPEAKER_00 33:49

Right.

SPEAKER_04 33:50

Yeah. So and and all all electricians and and technicians these days need to kind of have the basic understanding of Ohm's law, and the that relation between uh voltage, current, and and um and resistance. Um simply put, it's a it's a basic mathematical formula that affects all power transfer and electricity and wattage and power. Um and that's the the whole concept of your resistance times your current equals your voltage. Okay. But uh once you understand Ohm's law, look it up, then uh the nightmare behind the board there uh will start to look a little less uh intimidating, but uh but that's the importance of understanding all the theory, all the mathematics, because without that, then um you know we cannot keep this this uh industry moving in the right direction.

SPEAKER_03 34:45

And it's it's it's important to realize that DC is a it's a function

Ohm’s Law Common Mistakes And Resources

SPEAKER_03 34:50

of AC theory. It's just AC with frequency zero. There's there's a standard set of laws that electricity is gonna follow no matter what it's forced to, it has no choice. And um, depending on whether you're working with DC or AC, there's special cases in each.

SPEAKER_05 35:07

Excellent. Great comment, great, great discussion here. Now let's talk about some common mistakes by low voltage people, not electricians, right? So, Brandon, what are some of the common mistakes that you see done by low voltage people when it comes to volts, amps, and watts?

SPEAKER_03 35:22

So uh perhaps I didn't introduce myself correctly. I'm a German Ward. I'm not privy to a lot of mistakes that techs get to get to make. I'll let Matt answered that one.

SPEAKER_05 35:36

What about you, Matt?

SPEAKER_04 35:38

Well, you know, when it comes to power, um you know, we've said the term AC and the term DC. Okay, AC is alternating current, DC is direct current. Um of the major mistakes that I've seen is that uh people aren't understanding the difference, or they'll have a power supply. You know, I'll go back to um a commonly installed system that requires power supplies is uh access control and security. Okay, uh not all access control and security items um require um put it simply like this not all power supplies operate off of put out DC and AC power. Usually it's either or. Okay. Um if you're the installer in the field and you see that there's some power supplies and you know that you need to hook up a maglock, a magnetic lock set for a door, you need to be able to look at the maglock and see what its operating voltage and current is and if it's AC to DC, and then find the right power supply and hook up the right power supply to the right maglock. And I see common situations like that where people are installing a DC maglock on an AC power supply. Um, that is a common mistake that I see. Um, and it's just simply it's very, very different, it's very, very different in operating functions of each. Um but that same principle uh can be applied to many other aspects of uh of our industry and also voltage levels and current levels when it comes to power supplies and things of that nature, is that power is just not power, voltage is just not voltage. Um since a lot of the things that are installed these days are very, very unforgiving, um, you will let the smoke out. So I see people put the wrong the wrong appliance on the wrong power supply, whether it be an under voltage or over voltage situation, and just simply blow things up. Or they just put it on the wrong power supply.

SPEAKER_03 37:41

If it takes 70 volts DC, we can just use you know RMS AC. Nothing bad can happen.

SPEAKER_05 37:47

And sometimes that piece of equipment that it burns out, not cheap.

SPEAKER_04 37:51

No, and they're they're they're not cheap. You know, the a lot of things these days with solid state electronics, um, they are not cheap.

SPEAKER_05 38:00

Yep. So what are some resources? If somebody listened to this show and says, man, this sounds interesting. What are some resources or places that a low voltage person can go if they don't happen to live in Las Vegas and go to and go to your school? What are some resources for them to learn more about volts, amps, and and watts?

SPEAKER_03 38:19

So one of the good ones I've been digging in for are for resources for my students' website called uh all about circuits. And it can take uh any anywhere from a grade school approach to explain things to all the way up to uh engineering. It's where I find a lot of my resources. It's pretty user-friendly. Uh a lot of very good diagrams explaining uh anything from the basics to the engineering standpoint of where you get the square root of three for three phase.

SPEAKER_05 38:44

Matt, do you have any resources?

SPEAKER_04 38:46

You know, I all about circuits. Um you can even go to uh some of our manufacturers uh have pretty good explanations of power. And and I'll I'll use one manufacturer, for instance, uh Softing. On the Softing's website, they have some videos about POE that go into the some of the specifics on what actually it is and the differences between voltage and current. So and that's just one of our training manufacturers that we deal with. Um there are others, uh Fluka is another one that as well that has some pretty good product information details on there so that explain what the powers are in a very, very basic way because they want you to be able to use their products. So they're gonna help you identify some of those different variables.

SPEAKER_03 39:38

One thing I grabbed during COVID because we had the uh we we had to have the ability of showing things online without having anybody in person. It's really difficult to do a real-time uh analysis of a circuit with when you're at a distance, was a website called Every Circuit, which I think mine was a one-time fee of $20. But you can build just about any circuit you can imagine with uh switches, inductors, uh capacitors, and it'll give you the real-time uh values of them. You can it'll construct the real-time overtime wave functions for voltages across components, and you can superimpose them has been a really big uh benefit for my students.

SPEAKER_05 40:22

Do you have something you wanted to add there, Matt?

SPEAKER_04 40:23

Yeah, yeah, yeah. I was gonna say too, is that um for somebody that is also looking for information um on as it relates to power in our industry, um the FOA. Now everybody thinks FOA is just obviously just fiber optics, but it's really, really not. Um they have Lending Lightweave, but they also have Uncle Ted's. And Uncle Ted talks about premise cabling and the standards and and specifications for that. So and Uncle Ted's on the FOA, they actually have some pretty good explanations when it comes to uh those other other forces that we deal with. So um definitely if you're somebody that wants to learn more about those things and how it affects uh communications and premise cabling, um FOA is a good source also to uh to research and dig into.

SPEAKER_05 41:10

Fantastic show. That's what this is why I like to hang out with guys smarter than me, because you're teaching me stuff too, man. I like that. I appreciate you guys coming on the show today.

SPEAKER_04 41:19

Thanks for having us. Thank you, Chuck. Anytime.