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 Post subject: What is the best way to get started?
PostPosted: Wed Jul 01, 2009 8:05 am 

Joined: Wed Jul 01, 2009 7:19 am
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Location: Troy, Missouri
I am an electrical engineer who works for an OEM who produces industrial machinery. I have been asked to research Arc Flash calculations and what we need to do for NFPA70E compliance for our manufacturing plant. Is there a formal training format that reviews the data necessary to collect on the single line schematic of our plant, what information is essential before beginning calculations, and how to perforrm the calculations correctly?


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PostPosted: Mon Jul 06, 2009 4:30 am 
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Location: North Florida
From the sound of your question, it would seem you plan on doing the study yourself. First ask yourself if your prior training is up to the task. Like coordination and short circuit studys, it's not just numbers and equations in the end but also some understanding of electrical system design. If you're up to the task, then the collection of data to perform the study is the hardest part of the job, particularly in an older plant. You'll need cable sizes, lengths, breaker settings, relay settings, etc. before you begin the study.

It's good to know how to do the equations by hand and understand what they are doing, but for a system of any size you may want to consider purchasing software. The other advantage of this is once the model of the system is complete in the software, you can use it for relay coordination, short circuit, and many other studies. Each time you make a change to the electrical system, the new study is just a minor revision to the one line in the model.

If you decide to do the software route, most companies provide some basic training on how to use the software in a study including answering the questions you ask. I know EasyPower does this and I suspect the others do as well. You can go to the EasyPower web site for more info on this. Good Luck with your study - they can provide some interesting discoveries about your electrical system.

TxEngr


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PostPosted: Mon Jul 06, 2009 5:05 am 
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TxEngr makes some good points. To help obtain a better understanding, you can also check out these three articles about conducting the arc flash study.

[url="http://www.brainfiller.com/documents/ArcFlashJimPhillipsPart1.pdf"]Arc Flash Study Part 1[/url]

[url="http://www.brainfiller.com/documents/ArcFlashJimPhillipsPart2.pdf"]Arc Flash Study Part 2[/url]

[url="http://www.brainfiller.com/documents/ArcFlashJimPhillipsPart3.pdf"]Arc Flash Study Part 3[/url]

It can be quite an undertaking. I'm sure everyone here at the forum can help with questions you may have along the way. We all began at the beginning at on point in time and it is an amazing field.

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PostPosted: Wed Jul 08, 2009 12:42 pm 

Joined: Wed Jul 01, 2009 7:19 am
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Location: Troy, Missouri
I read the articles.... Thank you. I also realized as I was reading you are also the author and have an extensive background. It mentioned in the first article that you are a training instructor. I will check out your website for training programs. Do you have any formal recommendations for software or are you in a position that you need to remain nuetral? After reading the articles and thinking about the time frame upper management is "thinking" this task should take, I do believe I need to manage the expectations here also. Thank you.


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PostPosted: Wed Jul 08, 2009 12:54 pm 

Joined: Wed Jul 01, 2009 7:19 am
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Location: Troy, Missouri
TxEngr:
Thank you for your information. You are correct, the intention is to be trained so that I can perform the calculations and also help direct our other manufacturing facilities in getting ready for their analysis. Have you personally used the EasyPower software? I would like to understand the calculations so manually running calculations are intended but I also see the benefit of using software for future plant changes and knowing the calculations may need to be updated as addition and changes take place. I will check out the EasyPower web site to see what they offer. Thank you again.


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PostPosted: Thu Jul 09, 2009 6:35 am 
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Joined: Fri Jan 16, 2009 1:07 pm
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Location: North Florida
AA -

Yes, I personally use EasyPower software. This is my second industrial facility where I've used it. I'm currently completing the study for our plant which has 70+ medium voltage breakers, 120+ low voltage power circuit breakers with more than 50 MCCs. The last plant was about three times this size but we had several engineers working on the study. I agree with learning about the equations, but to do a facility with much equipment could become tedious. Also, if you're going to carry this to other plants, it's going to take up much of your time. In that case, I would definitly buy some software. Each package has it's advantages and I'm sure some of the folks here can give their opinion. I personally like EasyPower for it's user interface and ease of use. But my reference point is the SKM software back in the DOS days and their software has changed dramatically since then in terms of ease of use. Good luck with your study and you've found a great resource at this forum. I know I've learned a lot since coming here.

TxEngr


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PostPosted: Wed Jul 22, 2009 5:38 am 

Joined: Tue Feb 17, 2009 8:38 am
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Location: Westminster, MD
AlwysAsking?s wrote:
I am an electrical engineer who works for an OEM who produces industrial machinery. I have been asked to research Arc Flash calculations and what we need to do for NFPA70E compliance for our manufacturing plant. Is there a formal training format that reviews the data necessary to collect on the single line schematic of our plant, what information is essential before beginning calculations, and how to perforrm the calculations correctly?


AA?,

Your task is to get in compliance with 70E, so the very first thing to do is get the standard, obviously. But the reason I bring this up is that there's allot of work to do with matters other than the Arc-Flash calcs in order to get 70E complaint. In fact, you can get compliant without ever doing an analysis by following the "tables" alternative method for PPE requirements shown in 70E. Not that I recommend that at all, but it goes a long way towards a quick-fix.


As far as doing the calculations yourself, if you're capable, interested and qualified, have at it! It's an exciting career choice. But it's really just that, a career choice. You'll need to get very involved in the analysis in order to be technically correct. And you must be correct.... imagine being on a witness stand defending your calculation of HRC 2 over HRC 3 in an Arc-Flash incident.

My software of choice is SKM, having used it for 17 years. We have SKM and EasyPower at work.. some prefer EasyPower. Having as much experience with SKM as I do, I can attest that if you set out to do the analysis, SKM software and Tech support will give you the confidence needed to present technically-correct information.

John M


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PostPosted: Fri Aug 28, 2009 5:30 am 
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I worked with our corporation to purchase ESA's Easypower software unlimited buses with a corporate license for 2 seats at a time and installed the license on our network.

I had one of the largest one-lines ever seen by most. ESA did some debugging because of my structured layout and quantity of buses or impedance points that was modeled. The software works out great for our company.

I encourage you to attend the week training ESA offers. I worked with the software for a couple of years before taking the training. I still learned a lot of tricks to the trade during the training.


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PostPosted: Thu Mar 14, 2013 8:12 am 
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For the data collection part start with "FlashTrack" for the data collection. It is easy to use and a qualified worker can quickly collect all the data needed for the engineer it do the analysis using (in our case) SKM.

Note: FlashTrack is not for doing calculations, it was designed for the qualified worker to capture the data needed to model the system.
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 Post subject: Re: What is the best way to get started?
PostPosted: Wed May 23, 2018 4:11 am 
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I have been using EasyPower for about 14 yrs now and my data collector uses ESA OneLine Designer so that he can do some of the model building. I have always found that their tech support is outstanding! The best for software I have ever seen.

That said, doing an arc flash study does require some expertise in power systems and arc flash studies. There are many things such as choice of software settings, etc that will affect the outcome of the study. I have found errors in studies done by large firms that usually do design work or other power system analysis in their arc flash study. Many times just because the software has an arc flash module it seems like an easy way to expand their services. Usually I am reviewing an arc flash study for incorporation into a training program and/or electrical safety program and the client is not too happy when I tell them there are errors that drastically affect the incident energy values. Depending on the age of the study, they will back to the firm and the firm will redo the study and labeling or they will have a new study done by my firm.

Since this will be your first study, I will highly recommend that you hire an experienced arc flash engineer who also is adept at the software you choose, to be a mentor. This person can review your efforts to ensure you are on the right track in the beginning.

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 Post subject: Re: What is the best way to get started?
PostPosted: Wed May 23, 2018 6:51 am 

Joined: Wed Jul 12, 2017 6:06 am
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We use all three of the major software programs, SKM, ETAP and Easy Power. Each one has good and bad points but I find that we use SKM more and more on projects. ETAP seems to have more cable options for transmission lines in their library so if your site has much medium/high voltage distribution you may consider that.
Like others have said it is quite an investment in time and money for software and training to do these in house. Large corporations like DuPont for example have software in house and can do their own studies but most companies do not. The data collection is critical and can be time consuming, especially if you don't know what information you need. Trip unit model numbers, breaker types, relay settings all have to be checked and entered in the model. If its not a task you can be dedicated to, I would consider hiring folks that do it everyday.


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 Post subject: Re: What is the best way to get started?
PostPosted: Wed May 23, 2018 10:07 am 
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AlwysAsking?s wrote:
I am an electrical engineer who works for an OEM who produces industrial machinery. I have been asked to research Arc Flash calculations and what we need to do for NFPA70E compliance for our manufacturing plant. Is there a formal training format that reviews the data necessary to collect on the single line schematic of our plant, what information is essential before beginning calculations, and how to perform the calculations correctly?


Since it appears that this will be a one time study with occasional changes you may find it more cost effective to contract this work out to someone who does it for a living. I have been involved with companies that have tried to do it themselves either the study or the data collection and it has not gone well. The exception would be large companies that have enough of a staff and facilities to be able to devote resources exclusively to the project. Don't forget to factor in the yearly maintenance fee to keep the software current and allow access to technical support.

Data collection is a very essential part. I have been working with one company that does their own data collection and I am continually going back to them for more data. When my data collector is used, I don't have that problem as he has been trained and has done data collection for almost 10 yrs now.

The other issue with data collection is the PPE you need to wear. Typically we will use a 40 cal suit for the first couple of levels and then switch to a 12 cal system for the remainder.

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 Post subject: Re: What is the best way to get started?
PostPosted: Wed May 23, 2018 7:52 pm 
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Having worked at a mining facility, there really is no such thing as the ability to go out and do the surveys, yada, yada, yada, because the entire power system is basically reconfigured about every 6 months in their case as the mine advances. Some facilities are constants but others aren't even close. You start having to do more "modelling" in a general sense similar to a utility.

I have worked a little with ETAP but mostly SKM. By far SKM is the most flexible of the two and also the most buggy (version 6), and crashes frequently. With ETAP you are somewhat more limited on settings but it crashes a lot less and it's not as aggressive on licensing. ETAP doesn't make you label as many things as "buses" and doesn't count what are basically internal nodes (no branches) against your bus limit so the licenses are a lot cheaper. SKM as stated earlier was around in the DOS days and underneath it all the underlying "engine" is still the same stuff, just with a MUCH nicer front end. It was pretty much all you had to work with until others came along. One very nice feature is that when you run into some screwy equipment that's not in their already extensive libraries (at one time the largest one), you call them. If they don't have it they'll develop a model within a couple weeks. Really helpful on for instance very obscure fuses. Often though you call and they E-mail you the file in a couple minutes because they already did one of those, just didn't include it in the libraries because it's not as polished or in demand.

Only thing I wish I could do better is that with the mining stuff, wish I could somehow pull in data from the mine maps and somehow import/export it into SKM. I was kind of playing around with the very limited import/export capabilities of SKM and I think I was figuring out a way to do it and then I moved on to another job so I did some proof of concept stuff but never completed it. SKM let's you import/export tables of data and with creative use of this facility it is possible to export/import data into it. I made tons of use of it as-is doing some reporting things like listing what percentage of buses exceeded 40 cal/cm2 for instance or what percentage of buses were fuse protected as opposed to breaker protected. Even some creative things like what percentage of buses that were =<40 cal/cm2 became >40 cal/cm2 if we assume breakers fail and so we calculate arc flash at 2 seconds while ignoring all buses that are fuse protected. Was used to explain why breaker maintenance is important rather than simply throwing on 40 cal/cm2 suits and doing the work without maintaining the equipment properly under the false assumption that it will provide more than enough protection even if the breakers fail.


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