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Home > Videos >Arc Flash the Easy Way - Part 2, Data Collection
Arc Flash the Easy Way - Part 2, Data Collection

Of the overall time involved in an Arc Flash study, data collection can be the most costly if not properly planned. Eliminating the need for repeated trips to the site and avoiding excess delays and cost is the focus for this presentation. Second in the Arc Flash Risk Assessment series, this presentation emphasizes the benefits that can be recognized both in cost reduction and employee education when facilities maintenance teams are part of the process.

See the full transcript of the webinar below.

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Full Transcript of the Video

Jim Chastain: Good morning. Welcome to the second webinar in this four-part presentation on implementing an OSHA-compliant arc flash safety program at your facility. My name is Jim Chastain. I'm with the applications group here at EasyPower. One of the things that we're gonna try to pass along as we cover the material are areas, opportunities, where you as a tool owner could reduce the cost of compliance at various stages and interactions with the process of completing a study and maintaining your safety compliance as well as including your employees. Again, welcome all. We like to start the sessions with a poll question. And so if you would please participate, there's no obligation and certainly this helps us in terms of understanding the audience (00:01:00) and some cases directing the conversation as we go through it. First is who would you prefer to collect data for your arc flash study? Thank you. So here's how the audience responded. And then the second question, when an arc flash study needs to be updated, which option is more appealing?

Let's close this and share the results. And let's get on with the show. So the agenda has been modified slightly because some of the questions submitted at the last week's session. So I wanted to follow up with those online. And then as I promised, I want to start off with a very simple example, but for me it was very telling in (00:02:00) terms of my understanding of arc flash. And I would encourage anyone in the audience to include anyone on their electrical staff, especially anyone in maintenance, has the opinion that arc flash is really not that big a deal for your situation. And then we're gonna cover quite a bit about data collection, what it is, when it's important, how to do it. And hopefully cram that all into one hour.

So probably one of the best comments from last session was from someone who had experience or had worked at the Dow Chemical plant near Houston. And the statement was that all workers are trained, all qualified workers are trained that every disconnect requires a label and every label device requires arc flash PPE. So if a disconnect is missing a label, assume it fell off, stop and go review the study results. And so that, in my opinion, (00:03:00) is beyond just the letter of the law. It's very much an organization that understands the emphasis on worker safety and incorporating and putting the onus on the worker to make sure that everyone stays in compliance. The question came up, does NFPA 70E apply to power generation companies? Well it turns out in Article 90.2B specifically, the organizations or the installations that are not covered are ship-born, railways, communications equipment outdoors, and electrical utility controlled transmission lines and installations. And interestingly enough, a large segment of our EasyPower users include large utility providers, government agencies, people doing photovoltaic and wind farm installations, and even ship designers. And the question is why. (00:04:00)

This is my own personal opinion, but I think most of these organizations recognize that the safety of their workers is what's paramount for their systems, for their workforce. And EasyPower is a relatively simple way to ensure that their safety standards are met by implementing the guidance for NFPA 70E. The question came up, who pays for tools and personal protective equipment? And the response was I was too wishy washy with my response. And so I went and reviewed the matter. Turns out there was a specific release in 2008 that specifies because these are OSHA rules that anything the employee needs to cover in terms of their work conditions, work tools and PPE, the employer must pay (00:05:00) for and devise a method, if you will, to kind of monitor that those are being utilized in the workplace. So other resources for starters, the question was, is a copy of the slides available? The answer's no. We do record the session and distribute the link to anyone that's registered. But you'll see, both on our website and in the handout section of this webinar, some very useful references. EasyPower 10 Steps is a common sense approach to whether or not arc flash study is even necessary. And then the Practical Solutions to Arc Flash Calculations is the source material for this presentation.

So those are both free, and I invite you to take a look at them. This is what the covers look like. There was another, in fact the response to the poll question is that, well, we're just getting started. (00:06:00) And frequently, at that point you have to make a decision on whether to deal with it in-house or outsource it. Turns out the question is whether or not you need to have an engineering degree to do a study. IEEE's a little bit split on this. It comes down to basically the experience in conducting previous studies is what trumps a specific educational grade. So what you look for, whether you're doing the study in-house or participating with a study, who's conducting it, or selecting someone from outside, is to make sure they have experience in like systems as your plant and that you trust, because they're gonna come back with some recommendations, and all is for naught if you don't have the will to follow through what those recommendations are to improve the safety. Another (00:07:00) suggestion I would make is to keep your team involved at every intersection and learn, both in terms of especially data collection, what's important and what makes a difference in terms of the arc flash results. And then finally, no matter what, I would strongly suggest that you require a data file be delivered with the study.

The data file is actually the electrical digital representation of your system, and frankly, it's more valuable to you than to anyone else. So why not? I don't understand why there's a question there. Okay, I suggested at the end of the last session that you invite any maintenance team or any electrical workers that you have that have some doubts about whether or not arc flash is a serious situation. Because what (00:08:00) I'm about to go through is a very simple example of the use of EasyPower, and it conveys a conversation that I had, both of us, the electrician I was working with and myself, very long in terms of industry experience, and yet both of us did not seem to understand arc flash when we started this conversation. So what you're seeing here on the screen is the start page from EasyPower. And as we start a new one line diagram, it gives us the ability to, through the database, edit icon, or focus, draw a one line in this white area. And to do that, I'm gonna use the equipment pallette on the left vertical sidebar.

So I got a call from this electrician in Oklahoma. He had the responsibility of labeling all the above-ground electrical system for an oil field. (00:09:00) And he'd just purchased the tools. He said, "Jim, I have a problem with your tools." I said, "what do you mean?" He says, well, call him up, we got in a go to meeting session, and he described his one line diagram as we talked. And he basically said put a utility icon on the screen, then a two winding transformer, put a bus on the secondary side of the transformer, and on each end of this bus, drop a cable. So I did this, and as you can see, I just click on the equipment pallette and then click a second time on the drawing surface. And as long as I connect the dots, or touch each element, the tool makes a connection. Now you can see as I do this, there's a number of double asterisks, which indicate there's not an adequate amount of data entered for that system, for that element. (00:10:00) So each element in the system has a dialogue box. And so he said, "Jim, go ahead "and open up that first cable." If I double-click on the cable, it shows me the dialogue box for the cable. And you'll notice after we do a couple of these that there's the same general format on every element. And it lends itself to the intuitive flow workflow that people very much like about the EasyPower tools.

He said, "this first cable's a single conductor "for phase, it's a 1c cable. "It's THWN insulation, and it's a 350KCMIL diameter." He says, "it's 50 feet long." Now, you can see these red exclamation points. That means this is the requisite data to do a short circuit study. Once I've entered in this information, which describes a copper conductor through a steel conduit, I can calculate, the tool will calculate these ratios for me, along with (00:11:00) providing the cross-sectional ampacity for the cable. Now, he said, "the second cable's exactly the same "except for the length." So I'm gonna right click and copy on the first cable, right click and paste on the second cable. As we open up that dialogue box, you can see all the data's been carried over. He said, "the second cable is actually 1,000 feet long." So we entered 1,000 feet here. As we hit calculate, nothing changes because we haven't changed the construction of the cable. So we have the same ampacity. And because this is a ratio per thousand feet, these ratios stay the same. But now the tool knows precisely what the impedance is between bus two and bus three, and bus two and bus four, in spite of having the same cable. I'm gonna go up to the transformer.

He said, "I've looked at the nameplate on the transformer. "It's an oil-filled," and all this information comes off the transformer itself, the nameplate. (00:12:00) "It's a class OA, works with a fixed 65 degree rise. "It's a delta Y with the Y grounded. "Nameplate says it's a 1,000 kVA." Now, each of these dialogue boxes has the same general format and a series of tabs across the center. And depending upon what kind of study and which element, we fill in more or less of these tabs. So in the case of a transformer, we'd need to look at the impedance. Here again we have the red exclamation points. Vern said, "the impedance on this nameplate was 5.75%. "It didn't show the X over R or the zero sequence." So again, the tool will calculate those for me. And when I go to the TCC tab, by default we're gonna plot the damage curves when we get father down the road in the analysis. And all this is per ANSI 57.109.

Now you'll notice as we go through these, there's a pane (00:13:00) up here that's referred to as the media gallery. What this allows up to do as we're collecting data for our system is to take digital pictures and connect them with the element in question. So let's say here's the nameplate on this transformer that I've taken a picture with and saved to my hard disk. And now I can connect this to this data block. And at any point in time down the road I can inspect the contents of that picture. So it allows me to double check and save multiple trips to the field when I'm doing data collection. Now, we're also using a default number here for the utility. Normally the utility numbers will be provided by the local telco or utility company. And the numbers that are here are referred to as an infinite (00:14:00) source. So in his case, he said, "I have 55,000 amps available, "short circuit current. "The X over R is 7.4." He didn't have the numbers for the ground, single line to ground, so we're gonna use the same numbers to be conservative to represent the utility information.

Now, the reason I like this example so much is because he had a single protective device in his system, and it was a fuse in the utility cutout switch. So I'm gonna put this right here on the utility bus, open up the dialogue box. Now this is the first connection we've had to the device library in the tools. He said, "I've looked at the label on the fuse. "It's an AB Chance fuse link." And you can see as I'm going through this, the tool knows where I've placed it in the system, and it knows where to look on the manufacturer's catalog to pull up the parts. He says, "it's a model T," which I (00:15:00) remember distinctly, a size 10 fuse, and as we go to short circuit, when I click calculate and this number changes, I'm gonna start with zero, it changed at this location, which says, "okay, I found the part number "you just put together, Jim. "The manufacturers tested it to ANSI standard, "and the environment for the test was an X over R "equal to 15." The tool is gonna compensate that value for whatever environment the fuse sees in my system as I've wired it up. So at this point, he says, "okay, "go ahead and go to short circuit focus." Now if I made a mistake, let's say I put in an extra cable or I haven't terminated something, and I try to go to short circuit focus, the tool's gonna say, "Jim, are you sure "you know what you're doing? "Do you wanna see a report that shows the mistakes?" And sure enough, there's my cable that needs to be terminated and populated.

So I'm (00:16:00) gonna undo, there's an undo button here that just takes out the last step. And we're back to a clean one line diagram. So we go to short circuit focus, I just clicked on the button here at the top. We're gonna look at, excuse me, I am in I'm in my IEC mode, so let me change that. The system allows me to do, I can either consider ANSI or IEC calculations for short circuit. So back to short circuit, we're gonna look at a half cycle, bolted three phase fault. So this is the worst-case fault that can happen at any given bus, and we're gonna fault all the buses. And as we do that, we see some nice numbers and some pretty colors. And what this tells us if this bus, bus two, has a three-phase bolted fault, each phase coming from the utility will see 20,625 amps. Now, we (00:17:00) can look at all three phases, but since it's balanced and they're all the same, it's a little bit redundant.

If I go down to this bus and we experience a bolted three-phase fault, we'll see 17,667 amps. So this is the worst-case fault that this bus will see, and so it needs to be rated in terms of bracing and heat capacity to be able to handle this kind of a fault. Likewise, on this bus, the maximum current that a bolted fault would see is 4,340 amps per phase. He said, "okay, that's good." Now let's calculate instant energy. So that's this little burning man symbol up here with a lightning bolt striking the stick figure. As we invoke that, we see new numbers and new colors. And this is where the electrician said, "Jim, I have a problem with your tools." I said, "what do you mean?" He says, "well, right here, I can see "the arc flash boundary is 27 inches. "The instant energy is 2.3 calories per square centimeter (00:18:00) "at a working distance of 18 inches. "So I know what PPE I need to put on here." "It says down here the arc flash boundary's 28 inches, "2.5 calories per square centimeter, "so I know what PPE I need to put on "to work on bus three. "When I go 1,000 feet down the road, "now my arc flash boundary has almost doubled. "My instant energy's almost tripled. "And you're telling me I need to put on more PPE "to work on this bus hot." I said, "yeah." He says, "well, I've been an electrician for 25 years, "and anyone that knows electricity "knows that the farther away you get from the energy source, "the lower the energy's gonna be. "So what's wrong with your tools?" Well, my response to him was, "well, "I've been an electrical engineer for 25 years, "and I agree with you, Vern. "I don't understand why this energy's going up."

Well, the next step in any analysis, when I reach this point is to utilize this arrange (00:19:00) for arc flash icon at the top, which allows me to look at both the one line diagram and the calculations that were being made for the IEEE model. So at bus two, we can see down here it's a 480 volt bus. The fuse is a protective device upstream. This type of bus has an air gap of 25 millimeters. We already knew it had a bolted fault available, short circuit current of 20,625 amps. According to the IEEE model, the maximum current an arc will draw under these conditions, it's 10,345 amps. If we apply that much current to the fuse, the manufacturer says it will trip, or clear the fuse, clear the arc, in 68 milliseconds. If I go down to bus three, same voltage, same fuse, same air gap, now we have 17,667 (00:20:00) amps. IEEE says the maximum current an arc will draw is 9,064 amps. Under that conditions and at that current, the fuse will clear in 83 milliseconds. If I go down to bus four, 1,000 feet away from my transformer, same voltage, same fuse, same air gap, but now we're only exposed to a maximum of 4,340 amps. The IEEE model says an arc, if it were established under these conditions, would draw 2,732 amps. At that current, the fuse will blow in just under three quarters of a second.

So what that says, if I have on the same PPE that I used when I was working on the transformer, and I experience an arcing fault while working on this bus with the same PPE, that the explosion will go off in my face 10 times longer than it did back here. (00:21:00) Consequently, the PPE is not gonna be adequate. And both the electrician and I, in unison, said, "duh." I get it, time is everything when it comes to arc flash. And so in spite of maintaining the position that I knew everything about Ohm's Law, I really did not understand arc flash. And virtually every time I make this presentation to an audience that includes engineers and electricians that have not done a study, everyone values the fact that you can see what's actually going on in the system rather than just looking at data sheets. So thing I want to get across is there's a bunch of, if you will, examples or benefits from this simple example. One is how valuable the tool is actually looking at the system. Even from a lay point of view, there's a lot of things that make sense. (00:22:00) Secondly, the data file has a very high value, to me, if this is my system, understanding what the weak points are and how I can deal with it, especially when I'm looking at what-if scenarios for expansion or, down the road, changes. Secondly, it also makes it, I think, extremely easy to share and to teach people what's going on with not only arc flash but the different parts of my system with respect to other loads. And you'll see this as we get more into the data system. Because just by going through this one example, that makes me, frankly, better prepared to do data collection, understanding how important the timing element is on this arc flash calculation.

So the bottom line is, EasyPower tools will not make you a power systems engineer. But they will make it much easier for you to communicate (00:23:00) with your power systems engineering resources, be that a third party or a corporate facilities engineer or the design team or whoever it is that you work with on an infrequent basis. EasyPower makes it relatively easy to be on the same page. So I want to talk about modeling. And if I'm starting a one line arc flash study, my recommendation is to start with a very simple example of your one line, and essentially create a connection showing a one line at the simplest form between the utility source, whatever your power source is, and the lowest load, the farthest load that's gonna be required in the analysis of arc flash. And the reason for this is, in fact, this doesn't even have to be real data. (00:24:00) This exercise can be accomplished even before you start data collection. But the point is to represent the scope from the utility to the load that you want labeled and make it a very simple representation, and then try to go through the steps of doing an arc flash calculation to see if you get what you expected. And frankly I think it's even more valuable if you go through this process before you do data collection because it will reveal to you the important elements that need to be collected.

And if you don't see the results that you need, is that shortage due to a lack of data or inadequate data collection? Or is it due to an inadequate understanding of the mechanics of the tool? Answering those two questions at this stage will, frankly, (00:25:00) make you better prepared for collecting data. So essentially there's two parts to this particular step. One is the collection of the data itself. And at that point, we're obtaining the equipment that's required, the equipment data, the specifications on the equipment, that's required for an accurate power systems analysis. And then once that's accomplished, building the model is actually using the CAD tools to create a single line diagram and enter that data into the model. And as I say, at this point we're building up a database that can be extremely valuable. So one of the handouts, and you're welcome to request it from sales as well, is called Notes on Data Collection. And it's essentially the notes from the data collection class that we conduct on occasion, and we can do it on-site if that's required. (00:26:00) So the study results would only be as good as the data that's entered into the system model itself. With that statement, I do like to reiterate that if you go through the IEEE model and if you go through NFPA 70E, they still reflect that all of these, precision is not the bottom line as far as the analysis. All of these are results in terms of the analysis or estimates. And so there is at some point, especially if you have cable runs that are under the ground or in the overhead that you can't access, there needs to be some assumptions made. And you need to have a discussion, frankly, with, again, an experienced person on how to handle those assumptions.

Now, (00:27:00) just as a rule of thumb, very much between data collection and building the one line diagram is about 50% total of the project man hours involved. And so I would strongly recommend the more your team can be involved and the better they can collect the data accurately will benefit both as a cost of the investment in the study but also in their ability to understand the results when it's done and to implement any recommendations as a result. So rules of thumb that we use, just pulling things out of the air from experience, it's roughly two hours per substation and about five or six minutes per load. And then the data entry modeling and verification, which is debugging the technique, is about half an hour per bus and anywhere from five to 15 minutes (00:28:00) per device, depending upon the type of load. The main difference between an arc flash risk assessment and other studies is that you need to model the system in more detail. And that requires increasing the data collection time and the study effort.

If we were just doing short circuit study, that means we just need to collect the voltages and the impedances, if we're doing protective device coordination, then we need the short circuit current and trip settings and ratings for each device and element. And then if we're doing an arc flash risk assessment, which is all that data above and then the calculations for doing instant energy exposure at each bus, again, and we'll cover some of these additional details, needs to be comprehended as you're doing the data collection. So wherever possible, make sure you perform the data collection on de-energized equipment. Probably one of the more dangerous times (00:29:00) in the life of an electrician is when they're taking the front cover or equipment door off of a piece of equipment, and it's heavier than they expected, and for some reason that door or load shifts and accidentally falls into the hot gear. So you don't want to generate an arc flash while you're starting data collection. Frequently, this requires coming back later and or talking to the operations people to see if we can't schedule some downtime to do the data collection.

It's better to be, take a little extra time to do this stage of the game than to hurry it through and miss something or make conditions unsafe for the operator. Look for water, moisture, and any other evidence that there could be equipment failure as a result. And it's frequently, (00:30:00) doing data collection as part of a regular maintenance is also a good idea. And we'll go through a list of elements that we suggest including as far as preparation. It goes without saying that you don't want to leave with excess parts in your pocket because you forgot to put screws back in when you removed them. Now, you'll see later that as you're evaluating what the energy level is, the only way that any of these rules apply is if the equipment's been properly installed, properly maintained, and there's no evidence of equipment failure or malfunction. And all that has to be per manufacturer's directions. So cutting corners, maintenance or doing data collection is not a good idea. Start with (00:31:00) a plan of attack. Make sure that you're including as much information, tribal knowledge, in terms of equipment operations and where things are connected when you're doing the data collection.

Based upon the sketch, if you will, you can form templates or, one of our offerings is a mobile app that assists in data collection and allows you to sketch out one line diagrams, and then that file can be then imported to EasyPower. And we mentioned earlier that come back later is a good policy to have. And consequently, scheduling time and coordinating with operations so you're not interfering or the operators are not unaware that you may have equipment open that they're in the process of either starting or operating. So the more local knowledge, the better. We'll touch on that (00:32:00) later on. I mentioned earlier digital cameras. They're extremely valuable. And if you work in a system where you can take a number of images in a certain order, then as you get back to the offices or as you start to build a model, there's gonna be a system where you can organize or have the images organized such that you can use them in an orderly fashion. Okay, nameplates, huge, because frequently they have the equipment ratings and the details that you need for the data itself.

Any equipment that has adjustable settings, it's important to know the range and what the set points are. And specifically, if they're open or closed based upon the time that you visit, and how frequently they're used, and the alternative settings. Ideally, if you (00:33:00) have information from a previous study, you want to make sure that you're incorporating that. And probably one of the single greatest sins, if you will, of organizations that haven't done a study is they may often not have an up to date one line diagram. So coming right out of the chute, making sure you're producing a one line diagram that's accurate and representative of the plant as it stands is a very satisfying an accomplishment. Obviously on your plan of attack, you want to be able to finish one substation or distribution point before you go to the next. Again, start with a small section, review the data and make sure you've not missed anything. I encourage, go ahead and model it. Enter the data in the tool and make sure you're not missing anything when you're in the early stages so that you're not having to go back at a later time. (00:34:00)

Now, again this is part of the notes handout that I offer. But these are a list of recommended, a list of items that you need to take, including the tools and the camera. So we've talked about identifying all the equipment that's required for assessment. Now, even if it's not gonna have a label on it, many pieces of equipment need to be analyzed or included in the analysis because they will impact the arc flash ratings or the label will be required. So this includes any loads, any voltages and impedances, and anything that represents an X over R change. And very frequently these are large motors. Any protective devices, any enclosures, the condition of (00:35:00) the type of equipment, if there's a description of what air gap there is between conductors. Frequently the closest point of approach, or where the incoming conductors are connected in the main breaker or are connected to the bus work. Again, if it's not on the nameplate or it's not part of the description of the equipment or if it's been modified on a temporary basis, this observation needs to be recorded as part of the data collection.

Now, this is a good point. Arc flash hazard assessment is really only needed for those locations where workers are exposed. So you'll see this, if we have a policy of not working on hot equipment, do we need an arc flash label? Technically, no. The problem is, frequently the manufacturer requires work to be done while a load is in operations. (00:36:00) And so that basically contradicts company policy that says we won't work on hot equipment. Again, that comes down to company policy. Frequently, the scope of work for an arc flash study includes panels and switchboards down to and including 208 volt systems. According to IEEE instructions, 208 volt equipment with a service transformer of less than 125 kVA represents a low arc safety risk. However, most people include a label, because it has to have a label because of voltage. And consequently, because industry standards are kind of evolving, most 208 volt panels are being labeled with arc flash designations as well. (00:37:00) I'm gonna skip over most of this, because it's a little bit redundant. But short circuit analysis requires data on the utilities, the generators, so any source of energy, the transmission lines, the cables, the motors, and whenever possible, getting the nameplate data and a picture of it so that it's legible and can be carried with the file.

When it comes to equipment duty, EasyPower has an extensive library of manufacturers. And we can see that when we get into the tools next week. So again, EasyPower makes it relatively easy to enter this data. And often you can set up your default settings to include the typical values if you have common denominators, cabling and the like, or motors in your plant. We've talked about equipment data. The protective devices include relays, the CTs that are (00:38:00) used by the relays, the settings, delay types, and time dial settings. Fuses would include the type, the amp rating, the voltage, and the peak let-through current. Again, frequently that's gonna be on the manufacturer's data sheet. And in the case of breakers, low voltage power circuit breakers, the type, the fault clearing time, the pickup setting, delay curves, and then more to the point, especially as the evolving NFPA 70E requirements are, it is important to understand whether or not the protective device is reliable enough. Again, this requires some interrogation of the operators.

How frequently is this maintained? When was the last time it was cycled? Which is more an assessment of how aggressive the maintenance is and whether or not there's a concern about (00:39:00) a piece of equipment, even though it's behind a secured panel. The type, now, some of the things you'll see when we get into the tools, the fact that an arc, if it were to form, could be in an enclosure or in open air, will determine or influence the amount of radiation that a worker will receive or could receive. And so that needs to be assessed as I'm doing data collection. The grounding types and number of phases, whether they're accurately connected per the wiring diagram, and then the working distance for any task or procedure that needs to be in place for a piece of equipment that needs to be inspected or maintained while it's hot. And that working distance, you'll see in the tools, we set a default distance, usually of 18 inches. But if I have a procedure that requires me to reach inside of that boundary, I need to convey that (00:40:00) to the operator. And that should reflected in a hot work permit. Again, that's something that EasyPower tools can help us with as far as the base structure of the report required by NFPA.

There may be multiple configurations of the system. For instance, standby generators, tie switches, cross connects, backup substations, any one of which could mean that a different configuration of load and system supplies could be hot or in effect while we're doing maintenance, which could influence my arc flash exposure. All this needs to be comprehended in my data collection and so we need to describe what we call scenarios for those configurations. (00:41:00) And the recommendation is to label to the worst case. And EasyPower makes it relatively easy to do this. Now, this is a real quick list of the elements that are in the EasyPower equipment pallette. They range from the utilities, transformers, fuses, circuit breakers, switches, switch gears, generators, motors, panels, motor control centers, cables, busway, and overhead line, and the current limiting reactors. Each of these has a unique icon and a unique data dialogue box where the data needs to be entered. And again, as you're doing your simplistic design or your simple version before you start, you should pick out representative elements that are most typical in your system to make sure, as I say, (00:42:00) you've got the mechanics down and you're understanding the data that needs to be collected.

So real quick, let me kind of run through some of this, and then we'll touch on more of the cables. It's as important to understand the system elements that impact arc flash and what variations they might have inside of my plant, like insulation types, connection types, breaker panel styles, motor control center styles, transformers, all of which, if we have unique situations, need to be spelled out in detail, especially if someone else is doing the analysis. Likewise with utility data, there is an EasyPower, the icon you'll see down here at the bottom includes numbers. These are data that's required (00:43:00) for the calculation. But these are parameters that, frankly, is referred to as an infinite source. You might think that would show us that worst-case scenario. Well, it turns out if you utilize more realistic examples, as I did in the first example, you end up with a more conservative results, higher instant energy than if you started off with the infinite source. And again, EasyPower makes it easy to accommodate the different types of data that a utility company may supply. And as you saw, we'll be covering this as we actually do the model and the tools.

I talked real briefly about the fact that it's important to have the utility information as much as possible because using the infinite source actually ends up with less conservative examples. We can talk more about that in detail (00:44:00) when you have your information. Transformer data, for the most part, is included on the nameplate. And that's why taking a picture of the nameplate that can be associated with the dialogue box is important, both in terms of making sure you've got all the data and you don't have to do a second visit to the site for information or details that you missed, but it can also clear up questions that the engineer doing the study after the fact may have that was missed during the data collection process. And again, EasyPower makes it relatively easy to correlate all the required information from the nameplate. We'll skip through most of this. Again, much of this detail is in the Practical Solutions to Arc Flash Calculations. And I would encourage you to utilize that as well (00:45:00) as the notes from data collection.

The question that was I think came up earlier was okay, if nothing's changed in the plant, why don't I just re-run the study that was done last time and produce new labels? Well, one of the things you need to think about is, okay, even though we didn't change the equipment, how frequently has an off-shift electrician had to keep a system up by replacing a fuse, and he used something that was available in the truck rather than necessarily worrying about the fuse that was specified for that piece of equipment and then forgot, after shift change, to record the fact that he'd used a specific size? Well, frankly, that would change the arc flash calculations, and that's an important part of data collection, is to make sure all three phases, the fuses (00:46:00) are the same size, same manufacturer, and they are as prescribed in the one line diagram. So same thing is true with breaker trip settings or relay trip settings. If just for expediency's sake, an electrician or maintenance personnel has tweaked a relay to keep a system up and running and then for some reason did not record that change, that in fact can modify or change our results in arc flash. So it's not possible, with a high degree of confidence, to say nothing's changed in the plant. Not the least of which, utility data can change, and there's no obligation for them to tell us.

As urbanization expands and we may start off in a remote area where we don't have neighbors, as we conduct our first study. As the (00:47:00) utility company has had to supply other neighbors and other substations that will change our utility data. So again, as I'm redoing a study, I need to include updating my utility information at the same time. So again, breakers, any changes in breakers or set points, and you'll see as we get into details in molded case circuit breakers that they are, it's important to get the part number down correctly because frequently they do not have adjustable settings. And so the more specifics you have on the manufacturer, type, frame size, trip settings, and interrupt rating, the better off you will have your analysis. Solid state trips are probably the most difficult, especially on a piece of equipment that's (00:48:00) aged, or it's difficult to read what the settings are, the dial settings or even the range. And so again, this is where a picture can be extremely valuable. Frequently people will send a copy of a picture of a piece of equipment that they can't read the legend or the dial settings, and our tech support people can help them interpolate based upon the in situs, the orientation of the system around that device, and extrapolate or interpolate what the potential settings could be.

So we're getting close to the end of our time. May not have time to answer questions online, but certainly we'll cover everything via email and pick it up next session if we don't get there. One of the areas that comes up, though, for discussion (00:49:00) is what to do with a switch gear or a panel or a PLC where I potentially have low voltage and high voltage or 480 volt wiring such as this, and much of the system could be 12 volts or 30 volts, which doesn't require PPE, but somewhere up in the corner, I may have a breaker or a relay that is switching 480 volt current. Do I need PPE for that? The answer is absolutely yes. And that's the other reason for doing the study is to understand if I'm kind of doing an innocuous checking on some controllers, is that person exposing themself to an arc flash danger? So again, that will be part of the consideration when I'm doing data collection. Now (00:50:00) a real quick example, and looking forward to next week, one of the conditions that needs to be considered is whether or not the main breaker in a panel or a switch gear can be counted on to calculate or to limit an arcing flash. If you'll remember from last week's discussion, the fireball that surrounds an arcing flash can be as much as eight to 10 feet in diameter. And at the center of that fireball is gonna be a plasma ball. And it can be as much as five or six inches in diameter. And if there's not an arc barrier between the incoming conductors to the main breaker and me, if I'm working on this panel inside of a piece of switch gear, then an arc could be established on either side of this breaker, and that six inch plasma ball could breach (00:51:00) the effectiveness of this breaker and cause the arc to restrike on the other side of the breaker. Consequently, the main breaker in that situation cannot be counted on for protecting the worker.

You'll see how we make that, now, that information needs to be collected as I'm doing the data collection and needs to be passed along, then, to the analysis as a model is developed. And we'll talk about that next week when we get into the tool operation. Generators are a huge source of actually high energy, incident energy calculations because the lower currents that are usually supplied compared to the normal utility supplies will take longer to trip the protective devices. So consequently, special care needs to be put in place when we're looking at a configuration where the system may run for any amount of time on a (00:52:00) less stiff generator source than it would be on a utility. And again, this is all part of the EasyPower tools. And understanding and looking at these elements in the tool at the data entry stage will give you an understanding of what needs to be collected as you're doing data collection. Likewise with motors, motors are a very large source of current during the first half cycle of a fault. And that's primarily conditional upon the size of the motor and then what type of starter or what type of control are you using for the motor. So the specifics on the motor itself very often come from the data sheet. Very often they're not available if the equipment's old. And so there is the ability to come up with some standard values based upon the EasyPower inclusion (00:53:00) of IEEE and ANSI characterizations of those types of motors. And again, primarily entering a standard motor horsepower and voltage will cover a lot of those typical examples. But if you have specifics from the data sheet, those will improve the accuracy of the calculations. Cabling is surprisingly important in terms of X over R calculations and the compensation that needs to be made when we're evaluating whether or not test equipment or protective devices are adequate.

So understanding the manufacturer, the conductor size, material, the length of the cable, the type of insulation, the voltage, the number of conductors per phase, and whether it's going through a conduit, (00:54:00) a tray, or buried, all of which will have an implication on the impedences and then their reaction to a fault during the early stages of an arc flash. Frequently this is gonna require cleaning up a cable or moving things around. Again, a very dangerous time, if for some reason that cable's not securely hooked into the system, as I'm trying to scrape off some coating to find out what the size of cable is and that conductor shifts and for some reason comes out of the connection, it could be a source of an arcing fault. Bus ducts are unique in the way that they're characterized. And it's worth going through a typical example before I do data collection if my system has a lot of busways. (00:55:00) Likewise overhead line and a campus situation, there is actually a different type of arcing concern there. Frequently that's single line to ground as opposed to the three phase fault. Again, that can be covered by EasyPower tool utilities. And if we have current limiting reactors, that's something else that we would want to include in the modeling. And then relays, again they're a protective device. Everything that implicates their utilization including CTs and dial settings and manufacturer's data recommendations are all part of the data the needs to be required or collected. And this is easily accommodated by the EasyPower tools. (00:56:00)

So real quickly, in terms of constructing the one line diagram, my recommendation is to start with a very simple, minimal system, verify you understand the mechanics not only of building it but of populating the data dialogue boxes, and I'm gonna be able to produce the type of results I'm expecting. Then I'm able to go large. Now, there are some utilities in the tool that allow us to do a better job of laying out the system, especially if it's a very large system. And we have webinars on our website and the refresher session that talks about how to plan your layout so that you don't waste a lot of time scrolling and losing your place. And we'll talk about some of that, at least in reference and passing, next week. I also did want to, and you'll see, we have intentionally adopted the look (00:57:00) and feel of a Microsoft Office application, which again is another valuable feature that most users seem to appreciate. I did want to mention that we do have the industry's first mobile app for collecting data. It's called OnSite. It's a Windows 10 application. It can be downloaded from the Windows app store. There's more information on the website.

Certainly you're welcome to contact sales at if you have additional or need additional information on that application. Thank you all for attending. Next week we're going to be spending primarily the hour on demonstrating how the tool actually works. And we'll start with a simple one line diagram and then migrate to a more typical radial system that has multiple devices and potentially needs for coordination. And we'll be able to answer any questions that you have (00:58:00) at that time. For those of you that would like to get into deep technical references on this, I would encourage you to look at this list of recommended references available on the internet. I think the Conrad book is actually available from EasyPower, and you can purchase that online. If you have information or requests, more questions on any of this stuff, by all means let us know. Thank you for attending, and as I mentioned, we will answer the questions offline. And look forward to everybody joining us next week. Have a good day. (00:58:40)