arc density test

2085 Views 14 Replies 7 Participants Last post by nap, Jul 12, 2008

toolman001

Discussion Starter · May 17, 2008

I recently got a job to do for a large corp. We are installing a 600 and 1200amp service and connecting it to old existing equipment. This job is under the supervision of a PE who wants an arc test and I never heard of it.
To not look totally stupid I said I would find someone to do it. OK I am totally stupid but what I seem to understand is something to do with the total heat given off as measured in calories per cubic cm. I hope there is someone that can help me with this. Being stupid is not fun.:huh:

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nap

· #2 · May 17, 2008

well, you got me on that one. Not really sure what you are looking for.

BUT whatever is required should be in the job specs (engineers really like those) so that should explain what you are looking for.

If it isn;t and this guy just asks for this off the top of his head, this would be an additional expense (which engineers hate) so you get to ask him to define the parameters of the test he wants.

btw; there is a huge difference between ignorant and stupid. You can cure ignorant. (also nothing wrong with being ignorant. we all start out that way)

JohnJ0906

· #3 · May 18, 2008

toolman001 said:
I recently got a job to do for a large corp. We are installing a 600 and 1200amp service and connecting it to old existing equipment. This job is under the supervision of a PE who wants an arc test and I never heard of it.
To not look totally stupid I said I would find someone to do it. OK I am totally stupid but what I seem to understand is something to do with the total heat given off as measured in calories per cubic cm. I hope there is someone that can help me with this. Being stupid is not fun.:huh:

I think what he is looking for is an arc flash calculation.
Is this a 480 service?
If PE = professional engineer, this is more his job than yours.

Mountain Electrician

· #4 · May 18, 2008

I agree...it sounds as if he is looking for an arc flash analysis. If he is, thats a pretty involved job, although there are some good software packages out there to help out.

Speaking of arc flash, I'm curious as to what lengths companies are going to to institute NFPA 70E compliance includine arc flash analysis, training and PPE. It's a fairly hot topic in industrial circles, I've been to several seminars, and my main industrial customer is starting to incorporate it into their safety program, such as it is. Does any one have experiences to share?

nap

· #5 · May 18, 2008

that was my thought as well; arc flash calcs and yes, that would be the job of an engineer.

I still stand behind my statement that any testing should be in the job specs. If not, it would be up to the engineer to put the extra in writing so you can have record of it and you can charge him. That writing would specify what he was after.

randomkiller

· #6 · May 18, 2008

nap said:
that was my thought as well; arc flash calcs and yes, that would be the job of an engineer.

I still stand behind my statement that any testing should be in the job specs. If not, it would be up to the engineer to put the extra in writing so you can have record of it and you can charge him. That writing would specify what he was after.

Sounds like a new PIA to get taken care of, haven't had to do this yet.

HighWirey

· #7 · May 18, 2008

toolman001 said:
I recently got a job to do for a large corp. We are installing a 600 and 1200amp service and connecting it to old existing equipment. This job is under the supervision of a PE who wants an arc test and I never heard of it.
To not look totally stupid I said I would find someone to do it. OK I am totally stupid but what I seem to understand is something to do with the total heat given off as measured in calories per cubic cm. I hope there is someone that can help me with this. Being stupid is not fun.:huh:

Do not feel inadequate. New technology and continuing education is what seperates our trade from many others.

I was fortunate by having a local retired General Electric power engineer at my right hand during the last ten years, when some of the new stuff was beyond my grasp.

Your OP does indicate that the services of a degreed engineer are required.

Work'in For That Free Tee . . .

toolman001

Discussion Starter · #8 · May 18, 2008

Arc flash is what he wants

Thanks so much for all the responce, you are right arc flash is correct however,when he discribed it to me the term arc density was used. I just listened and felt I was on the verge of new knowledge. He also said that several of the big manufactuers had schools on this test I want to learn.

nap

· #9 · May 18, 2008

arc flash deals with energy density at a given distance. Sounds like he may have been BS'ing his way through this as much as you were.

but, since you do say that for sure, try this:

http://www.arcadvisor.com/arcflash/ieee1584.html

that may help you familiarize yourself with what is happening. There are other sources as well. If you go to the NFPA website, you can read NFPA 70e which deals with this.

nick

· #10 · Jul 11, 2008 (Edited)

arc flash test

its done at the factory . for a test to rate your gear but only on gear thats ul testing stuff not new gear going out to a job meaning a factory test to max out the buss or breakers insulators to see how much they can take under fault conditions , like square d or general electric but not in the field its about the most dangerous test to perform your going to short one leg to ground or phase to phase to read amps volts and see how the aic rating is ? tell him to do this himself and youll will watch , no one in there normal state of mind would do this on new or old gear in the field , your going to stress out your buss your equipment to the limit , have the factory look at this call the manufacturer , and ask yourself why anyone would do it ? for what reason it is basically not a good thing .but iam not a expert just a electrician and there maybe a reason i like to hear why / he may mean a current in rush test now thats different we do that stuff in the field ? or maybe a arc fault test ? arc fault study yes / best of luck to ya my apology to all the above responses i really was thinking a real test was what was to be done ,

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nap

· #11 · Jul 11, 2008

Did you miss the last post from the OP (which btw was alsmost 2 months ago):

Arc flash is what he wants
Thanks so much for all the responce, you are right arc flash is correct however,when he discribed it to me the term arc density was used. I just listened and felt I was on the verge of new knowledge. He also said that several of the big manufactuers had schools on this test I want to learn.

the engineer was after a calculated arc flash density report, and not an actual test. Obviously you aren;t going to do a dead short flash tet in the field. You do that and it is time for new gear. Wouldn't make much sense now, would it?

nick

· #12 · Jul 11, 2008

arc flash

ya , i get reading too fast and dont check the dates sorry nap, we just read the first two post and went crazy , i really should read each but i rush around and never look at the dates . and now i have a question is this test what they used to call a short circuit or coordination study or is it a different area of safety requirement on just some projects or some new engineering thing in the specs on jobs , sorry nap ill start checking the dates my mistake .

nap

· #13 · Jul 12, 2008

Not a huge deal. Sometimes the additional info is a benefit to everybody. Sometimes the late poster is expecting an answer, which typically never comes.

go up a couple posts and click on the link I have in my post. It will help explain the arc density calculations.

nick

· #14 · Jul 12, 2008 (Edited)

arc fault

yes ,thanks nap its all clear now they are different calulations but deal with faults , arc fault one for safety ppe and working clearance and that coordination study one for breaker up and downstream faults pipe type distance wire it makes sense now . but who will really uses this ? the enginneer meaning the arc fault analysis part to cover there job specs. i see it as a osha req, and asked for by job pe but what real purpose is it to the electricians working out there , i know we have safety equipment on our jobs when they work hot stuff ,but have never heard of this ,i know its a good thing on paper looks good but do electricians really work by these guide lines. so if the dead fronts is off the switchgear you have to wear a complete suit of protection which limits your view and you cant work or move your hands to do your work. ive worn a hot suit once it was 98 deg. outdoors in florida sun, i wear glasses and had a face shield , suit complete gloves ya know , we were just checking phase rotation on a transformer ,i could not see the terminals do to fogg in my view . and could not see the tester lites .but our safety guide said it must be done it was more dangerous with the suit ,anyone had this happen?

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nap

· #15 · Jul 12, 2008

I see it as an engineer trying to push his work off on to others. Those others should not really be doing this as it is engineers work.

Same old thing as usual. The more disclaimers the engineer can lay on us and the more work they should be doing they can lay on us, the less liability and work they have to do.

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