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Beuwolf_1

Arc Flash Documentation

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Yes, thanks for the extra documentation. We are going to be implementing arc flash here in the very near future, and the insite has been very helpful. For tthose of you that have had more experience then the rest of us, I do have a question still. When all is said and done, and you have a system implemented, what happens if the electrial demands change with short notice? For instance, we seem to be stuck in a "5S" and "Lean" senerio where the Lean team takes great pride in moving equipment all over the plant. Does this require a new review of the electrical system? Or does this mean that moving equipment from point A to point B has no effect on anything but the buss itself? Thanks again, Beuwolf

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I'm kind of in a similar situation. We are getting ready to do a lot of equipment moving. For the incoming power Arc Flash calculations, I used the specifications from the power company. On all down stream equipment, I did the calculations off of an infinite buss. By doing this as long as moving the equipment does not mean changing it to a different distribution transformer, in theory the the Flash protection boundaries will remain the same. Probably the only time this would not be a safe bet is if your fuses that in most cases are the weakest link in the Arc Flash are not located on your machine which they should be anyway. We do have a few machines that doing this hurt us on but we are adding fuses to these machines to get the category down where it should be Another problem with accounting for distribution for Arc Flash protection is what if the power company increases the capacity of the grid or hook you into a different grid. They aren't going to take the time to call every person on the grid.

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I Received training on Arc Flash back in May and we are starting a committee to implement the requirements. The training was pretty helpful, but what may be more helpful is a web cast that I found that you should be able to show your people and I think that it will be counted as part of the required training. Here is the link http://web1.media.globix.net/client/planteng/2006_0518/19165/launch.htm If anyone has any hints that might help me I would appreciate them. I am looking at using "Easysolv" software to calculate the boundaries and the make the labels. Has anyone used this program and if so what did they think of it. Mark

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I played with a demo but I was a little too much software for me. I was looking for something that was strickly for arc flash. The software did more than that and more than I wanted. Have you thought about doing the calculations yourself?

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No are the calculations easy? Do have the formulas or know where I can find them.

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Do you have the NFPA 70E? I would suggest getting the blue book. Do you have one wires for your plant? Do you have a firm understanding of your plants distribution?

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Already have the 70E, have not gotten a chance to read much of it the Safety Manager has it. The plant currently does not have a one line, working on one now. Plant is pretty small, understand basic distribution.

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Read the 70E and get your one lines done before you do anything whether it be purchasing software, hiring someone to do it, or doing it yourself

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My Elecrical Supply house is doing a FREE arch flash seminar. Arc_Flash_Seminar_09_27_06.pdf

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Chakorules, I know you are an OEM so currently you don't have to really deal with Arc Flash I would strongly suggest you still go so you will be familiar with what customers are asking for when they are discussing lowering the incident energy.

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convenient excuse to get out of office and it even comes with free lunch but... gee... would you look at the fonts, colors and shadows in that invitations? reading it sure makes me see flashes...no, I'm blind...

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I've been sorting through about a 2 foot thick stack of notes on arc flash protection trying to clean up and hated to just throw it away so I have began turning the notes into articles. In the end it will be 25 to 30 articles total but I have publish some of them if anyone would like to have a look http://www.twcontrols.com/index.php?option...1&Itemid=38

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We just finished our study, by changing a few breaker settings, we were able to get most of our site catergory 0 or 1, with a few 2's at the switch boards, and we have one older Reliance drive that is a 3, mainly due to the isolation transformer. Our standard uniform is FRC coveralls and goggles anyway (because of flammable chemicals), so it didn't impact us too much. However our outdoor switchgear is dangerous (greater than 4). We can live with that, because it is remote to the rest of the plant, and we almost never have to deal with it anyway. I do have a question though. If you have a control cabinet, with 120VAC feeding a PLC and a 24v DC power supply, with all DC I/O, and you need to connect an additional output or two. Can you do so without killing the 120? Is this considered working on live electrical ?

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Nice guide TW. A few recommended changes: Alter the last page so that it says the lowest category is 0, not 1. Add footnotes stating the origin of your materials and charts, and where is the 10 page disclaimer?? Just kidding. I would repeat that it is just an informational guide at the bottom or top of each page. Also the IEEE 1584 calculations are supposed to be better than the NFPA 70E. I don't know why, maybe you could point out that they exist anyway in your guide. Excellent effort. Thanks. We had similar results in our plant. We were able to reduce to mostly all 0's and 1's, by changing breaker settings and fuse types. We found a big problem with C.B. short circuit ratings on alot of our added over the years C.B. panels. Fortunately series ratings from Square-D covered alot of it. We just finished our second building, and everything was pretty low because the transformers were smaller, except for some dangerous ratings inside the switchgear. Edited by GerryM

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Any cabinent that contains above 48 Volts requires shock and arc flash protection. So yes, even though it is just one wire going to your PLC and you may be adding an output on the opposite corner of the cabinet PPE is required I have an article that goes into depth on just that subject but waiting for reprint permissions from the NFPA and OSHA

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Hopefully the PPE required is only a Cat.0 in that case, so its really not much anyway. That would be a nice article to see.

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Citing directly out of the NFPA 70E and a few OSHA articles so wanted to get permission from them. Hopefully I will hear from them in a week or so and they will say yes

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What this means is that you have to use your voltage tester on a known energized source of the sample voltage (scale on the meter). this verifies that he voltmeter is working properly. I have had meters fail and read a lower voltage than was actually there and I shut down the whole plant, trying to minimize undervoltage damage to the machines. We checked the voltage with a different meter and everything was correct voltage. The checks that has to be done to make sure that the machine is electrically dead with a multimeter only apply to someone working directly on the circuit. For a mechanic verifiication of the machine not working. Trying to start is all he has to do.

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Ken, I went ahead and put up Part 21: When do you actually have to follow Arc Flash Guidelines http://www.twcontrols.com/index.php?option...2&Itemid=38 Tell me what you think

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Not bad, I thought that was going to be the ruling. Just hoping there was an exception that I had over looked. Our standard "uniform is FRC Cat. 2 rated coveralls and googles, so whenever a maint. person enters a PLC panel he will already have all the required PPE. All of our plc panels are cat. 0.

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