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 Post subject: What To Label Panel?
PostPosted: Thu Nov 05, 2009 8:16 am 

Joined: Wed Oct 29, 2008 6:05 am
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See the attached pic.

What PPE CAT and IE level should I label the 208/120 Panel?

Thanks


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PostPosted: Thu Nov 05, 2009 10:24 am 
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PAult wrote:
See the attached pic.

What PPE CAT and IE level should I label the 208/120 Panel?

Thanks


Well, what the study says, HRC 3. However, I would question these results, do you know all the info used for the calulation?


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PostPosted: Thu Nov 05, 2009 10:38 am 
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Location: Lawrenceburg KY
This is what my label would look like. This would be for three phase not single phase.
My calculations does not include your upstream utility data. :)


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PostPosted: Thu Nov 05, 2009 2:13 pm 

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Zog wrote:
Well, what the study says, HRC 3. However, I would question these results, do you know all the info used for the calulation?


See the attached for more detail, using IEEE 1584 study in SKM. Basically at the max clearing time of 2.0 Seconds.

Since this Xfmr is <125 KVA and it is 208V would you label it any different?

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PostPosted: Thu Nov 05, 2009 2:20 pm 

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THE CABLE GUY wrote:
This is what my label would look like. This would be for three phase not single phase.
My calculations does not include your upstream utility data. :)


I like the label.. Looks like this is generated from easypower? Do you do a study on all your transformers <125KVA? why 2* rather than 3? Did easy power calc this?

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PostPosted: Fri Nov 06, 2009 10:47 am 

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With all the <=125KVA transformer and 208VAC arc substaining issues I think I will just use the 70E table for this application and label it with HRC 1 and an 4ft AFB.

What does everyone think?

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PostPosted: Fri Nov 06, 2009 1:17 pm 
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PAult wrote:
With all the <=125KVA transformer and 208VAC arc substaining issues I think I will just use the 70E table for this application and label it with HRC 1 and an 4ft AFB.


Well, I'm one who HATES using the Hazard/Risk Categories and 70E tables.

I haven't had to do this yet, so who knows what the final product would be, but since the transformer is only 75kVA, I would avoid putting a calorie rating on the label if I could, but would include a minimum PPE as all natural fiber, long sleeve shirt and pants, hard hat, face shield, and gloves.


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PostPosted: Fri Nov 06, 2009 1:19 pm 
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Location: Spartanburg, South Carolina
Exception No. 1 to 130.3 indicates that an arc flash hazard analysis is not required for 208V panels served by single transformers less than 125 kVA. IEEE Std 1584 states that

"The arc-flash hazard need only be considered for large 208 V systems: systems fed by transformers smaller than 125 kVA should not be a concern."

The clear implication is that an arc flash hazard does not exist and that because the arc will not self-sustain, the IE will be less than 1.2 cal/cm². I believe that labelling to require Category 0 PPE, 1.2 cal/cm² PPE, or even not labelling would be acceptable to meet NFPE 70E requirements. The NFPE 70E handbook for 130.3(C) states that

"Only the equipment where the incident energy level is greater than 1.2 cal/cm² needs to be marked, but that decision depends on a facility's safety program."


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PostPosted: Tue Nov 10, 2009 7:14 am 

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jghrist wrote:
"Only the equipment where the incident energy level is greater than 1.2 cal/cm² needs to be marked, but that decision depends on a facility's safety program."


I thought everything that may require service while live needed to be labeled?? I cannot find anything in 70E where it says only greater than 1.2 cal/cm2 needs to be labeled, what section is this in?

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PostPosted: Wed Nov 11, 2009 7:37 pm 
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Before that quote, I wrote
Quote:
The NFPE 70E handbook for 130.3(C) states that

This is in the handbook and not in the NFPA 70E text, so it is not governing, but the requirements for arc flash hazard labelling are all for locations where there is a potential arc flash hazard as defined in Article 100.


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PostPosted: Thu Nov 12, 2009 1:52 pm 
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I would suggest a label at least to include HRC0 because you do not want to forget about the shock hazard and associated hazard boundaries.

I also recommend that the "Fed from" information is posted on the label to let the customer or worker easily ID the upstream protective device.


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PostPosted: Mon Nov 16, 2009 12:58 pm 

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jghrist wrote:
Before that quote, I wrote

This is in the handbook and not in the NFPA 70E text, so it is not governing, but the requirements for arc flash hazard labelling are all for locations where there is a potential arc flash hazard as defined in Article 100.



Since the NEC 110.16 requires some kind of label on the equipment we are going to put the PPE category and the minimum required PPE on the labels. If we didn't label this panels with the required PPE wouldn't we have to use the tables to determine it?


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PostPosted: Mon Nov 16, 2009 4:29 pm 
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Quote:
If we didn't label this panels with the required PPE wouldn't we have to use the tables to determine it?

Hello PAult,
I hope we are not confusing you.
I would just set your own method and not worry about the tables.

Basically, you need a company standing statement, training and noted in your final report of how to handle the HRC for task when working on this type panelboard and referencing the NFPA 70E exception to 208vac,<125KVA.

IMO, you can make this a HRC1, HRC2 or HRC3. Just make the decision and stick with it for all situations with such criteria. It’s the best thing you can do until something more definitive is determined.


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PostPosted: Tue Nov 17, 2009 7:45 am 

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THE CABLE GUY wrote:
Hello PAult,
IMO, you can make this a HRC1, HRC2 or HRC3. Just make the decision and stick with it for all situations with such criteria. It’s the best thing you can do until something more definitive is determined.


Thats what I will do.

Thanks for the Help!!


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PostPosted: Fri Dec 04, 2009 2:07 pm 
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This looks like SKM


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PostPosted: Tue Jan 19, 2010 5:08 pm 
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Low Arc Flash Hazards

The attached file is what I use for all panels/enclosures fed by single source transformers < 125kVA, V<=240. We label for uniformity and clarity.


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