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PostPosted: Wed Jun 03, 2009 1:23 pm 
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I discussed this topic directly with Ken Mastrullo from OSHA yesterday. He said, and I am paraphrasing: you do not have to perform the risk analysis, but this doesn't exempt you from wearing PPE. He implied you still need to use the tablular method, you just don't have to worry about meeting the criteria in order to use it.


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PostPosted: Wed Jun 03, 2009 6:44 pm 
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I've can't seeing where it explicitly said that. But if you read the IEEE 1584, they state that they were unseccussful in establishing an arc. If there is no arc, there can be no arc flash. So at that point you can use whatever PPE you think appropriate. HRC 0 is what I usually use as min.

The real question might be if you could use the old -1? No analysis, no arc, so why not no sleeves. -1 was fine for years so why not now?


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PostPosted: Thu Jun 04, 2009 3:49 am 
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No Arc

I don't disagree with you, but this is the message that the driver of NFPA 70E for OSHA, is saying. Ken is the one who is training most of the compliance officers. In New England we are seeing a high level of enforcement with regards to Electrical Safety.


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PostPosted: Thu Jun 04, 2009 8:29 pm 
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Well, we are all individuals with our own opinions. Ask Ken to specify the regulation within 1910 so you can look it up. It doesn't exist. So he is applying his personal interpretation of 70E. That doesn't make him right. If there was an incident, and you have a program in place that conforms to the general outlines of 70E, ask him if you could be cited under the General Duty Clause. I don't think so because you can only be cited if you don't have a program. There is no way OSHA can cite you on a nuance which defaults to a PPE that is not specified. Or rather, they could cite you, but you'd win on appeal or review. With that said, you should still know better. The only requirement that I interpret to be required, based upon the reading of 70E, and this would be an absolute minimum, is that the person performing the work not wear meltable fibers, which would be HRC-1 as a minimum. In the 2009 edition there is no mention of HRC-1 being repealed, or a synopsis of a study that shows a number of injuries when HRC-1 was used appropriately. It is NOT part of the 2009 edition so it can't be used if you are following the task table. But it would still meet the requirement for a no analysis required situation. This is not the policy I follow or recommend, but we are strictly discussing Code here.


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PostPosted: Mon Jun 15, 2009 10:26 am 
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John Perrotti wrote:
I discussed this topic directly with Ken Mastrullo from OSHA yesterday. He said, and I am paraphrasing: you do not have to perform the risk analysis, but this doesn't exempt you from wearing PPE. He implied you still need to use the tablular method, you just don't have to worry about meeting the criteria in order to use it.


I had the oppertunity to attend one of Ken Mastrullo's seminars and didn't agree with his tendency to discount actual IE analysis in favor of the tables. When questioned on this his response was calculating IE wasn't necessary. Sounded a little strange coming from a OSHA rep. I don't agree with Ken or the tables because... IMHO it's an attempt be a "one size fits all". I've see situations where the calulated IE exceeded 40 cal/cm^, yet the tables list it as a cat 2.


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PostPosted: Mon Jun 15, 2009 12:25 pm 
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Table Exception

All of the above information and comments tells us we are still a long way off with the rules and regulations pertaining to NFPA 70E.

Everyone must really keep in mind, the best method is shut it off. All of the risk analysis', studies, and documentation will never need to be put to test as long as we can deenergize.


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PostPosted: Mon Jun 15, 2009 12:30 pm 
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haze10 wrote:
But if you read the IEEE 1584, they state that they were unseccussful in establishing an arc.


No, they say they were unsuccessful in sustaining an arc, not establishing an arc. There will still be an arc, it just wont need an OCPD to clear it.


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PostPosted: Mon Jun 15, 2009 12:33 pm 
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haze10 wrote:
Well, we are all individuals with our own opinions. Ask Ken to specify the regulation within 1910 so you can look it up. It doesn't exist. So he is applying his personal interpretation of 70E. That doesn't make him right


Take out your 2004 70E and look at who the chair was, look at the cover of the 2004 70E handbook and see whos name is on the cover. I think his "personal interpretation" is better than any of ours, and he is now the head of the 70E enforcement for OSHA and training all the compliance officers, so they may share his interpretations.

Not saying you are wrong, just saying that that is an arguement you will probally lose in court.


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PostPosted: Mon Jun 15, 2009 12:34 pm 
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short-circuit52 wrote:
I've see situations where the calulated IE exceeded 40 cal/cm^, yet the tables list it as a cat 2.



Interesting, and this situation were all the variables within the limitations of the tables?


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PostPosted: Thu Jun 18, 2009 9:49 am 
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Zog,

I stand corrected listing cat 2... should have been cat 2*. Typo. As for your question:

First, I didn't like the tables in the 2004 edition and dislike them even more in the 2009 release. I was involved in a sitation where the customer has a 1500 KVA, 27.6 kV to 0.480 kV, 6.18 %Z, delta/delta xfmr suppling a switchgear bus. The primary side OCPD is a 50 amp type K fuse link, no OCPD at the secondary terminals, with 5 each 3c/500 mcm cables - 100 ft run connecting to the switchgear bus. Utility availabe fault current = 7kA.

Being a delta/delta xfmr, the 25 ft tap rule doesn't apply and no secondary OCPD is required. As long as the pri to sec voltage ratio x cable ampacity is = 150% or less of the primary PD, it's good to go. The xfmr is protected the primary fuse links only. Ok... this meets NEC for acceptable installation.

Running the short circuit and IE numbers for the switchgear bus terminals at the end of the 100' cable run results in a 27.3 kA fault current and 89.6 cal/cm^ at 85% (14.8 kA)Ia. Clearly an "Energized Work Not Permitted" situation.

Joe the Electrican needs to measure the bus voltage. Looking up the NFPA
70E table for "600 volt switchgear voltage testing" it lists cat 2*. Joe dons the required PPE and opens the back of the switchgear cabinet exposing the energized 480 volt bus, and proceeds to drop the uninsulated adjustable wrench shorting the bus bars.

He wasn't killed but is badly burned and spend the next 3 months in a burn unit getting dead skin scraped off. Along with destroying $70,000 worth of switchgear bus duct. His supervisor didn't want to spend the money for a short circuit study instead opting to buy a copy of NFPA 70E and photo copying the PPE tables. Now the company is embroiled in a million dollar law suit.

The problem is NFPA 70E doesn't correlate very well to NEC. It takes someone with electrical experience as well as NFPA 70E knowledge to put the two together to find potentially dangerous situations. In this case it was the delta/delta xfmr only having primary PD.

Doing a study involves evaluating the entire system in question. Many times I find wrong trip setting and improper fusing. This costs the customer nothing to correct.

I'm not knocking Ken Mastrullo. He's done allot of work with NFPA to improve electrical safety but IMHO has too much ownership in the tables he helped develop. Do I think he's biased... yes.

Would you be comfortable under going open heart surgery because your doctor based his decision on a "typical" symtom he read from a medical book?


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PostPosted: Thu Jun 18, 2009 10:24 am 
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short-circuit52 wrote:
Zog,

I stand corrected listing cat 2... should have been cat 2*. Typo. As for your question:

First, I didn't like the tables in the 2004 edition and dislike them even more in the 2009 release. I was involved in a sitation where the customer has a 1500 KVA, 27.6 kV to 0.480 kV, 6.18 %Z, delta/delta xfmr suppling a switchgear bus. The primary side OCPD is a 50 amp type K fuse link, no OCPD at the secondary terminals, with 5 each 3c/500 mcm cables - 100 ft run connecting to the switchgear bus. Utility availabe fault current = 7kA.

Being a delta/delta xfmr, the 25 ft tap rule doesn't apply and no secondary OCPD is required. As long as the pri to sec voltage ratio x cable ampacity is = 150% or less of the primary PD, it's good to go. The xfmr is protected the primary fuse links only. Ok... this meets NEC for acceptable installation.

Running the short circuit and IE numbers for the switchgear bus terminals at the end of the 100' cable run results in a 27.3 kA fault current and 89.6 cal/cm^ at 85% (14.8 kA)Ia. Clearly an "Energized Work Not Permitted" situation.


Very common problem for Industrial plants. In fact I am giving a presentation on mitigation methods for this very senerio at the Sept EPRI conference.

short-circuit52 wrote:
Joe the Electrican needs to measure the bus voltage. Looking up the NFPA
70E table for "600 volt switchgear voltage testing" it lists cat 2*. Joe dons the required PPE and opens the back of the switchgear cabinet exposing the energized 480 volt bus, and proceeds to drop the uninsulated adjustable wrench shorting the bus bars.


Insulated tools insdie the LAB would have prevented this. I know you know that but it is that simple. Sounds like a lack of training, understanding, and real Electrical Safety programs at your plant is the guilty party here. As you point out later in your post.

short-circuit52 wrote:

The problem is NFPA 70E doesn't correlate very well to NEC. It takes someone with electrical experience as well as NFPA 70E knowledge to put the two together to find potentially dangerous situations. In this case it was the delta/delta xfmr only having primary PD.

Doing a study involves evaluating the entire system in question. Many times I find wrong trip setting and improper fusing. This costs the customer nothing to correct.


I could not agree more, well said.

short-circuit52 wrote:
I'm not knocking Ken Mastrullo. He's done allot of work with NFPA to improve electrical safety but IMHO has too much ownership in the tables he helped develop. Do I think he's biased... yes.


Well they are his baby, and are a good tempory solution until a real hazard analysis is completed, I think Ken would agree that is the intent of the tables.

short-circuit52 wrote:
Would you be comfortable under going open heart surgery because your doctor based his decision on a "typical" symtom he read from a medical book?


I wish I had a niclel for every time I have said that.


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PostPosted: Thu Jun 18, 2009 11:19 am 
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Zog,

Yes, insulated tools are cheap insurance and would have probably avoided a shorted bus. And yes, training and monitored compliance by the company was lacking. People are resistant to change and dislike wearing PPE... I've heard it all. It's hot, gloves make me more apt to dropping tools, face shields are uncomfortable, etc. On the management side it's "we have to cut spending.


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PostPosted: Thu Jun 18, 2009 7:46 pm 
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I just consulted with a fortune 500 manufacturing plant on their arc flash program. I tried to convince them to go the IEEE IE route. But after getting quotes on the engineering, they opted for the Table method. Companies are strained for cash and in survival mode. Is it reasonable that they be forced to invest some $30 to $70 thousand on engineering for analysis when they can use the Table. I do not believe we need a Table that is 100% accurate in all applications. If you study Hazardous Area Classification, NFPA 497, you learn that the code is designing against a 'two mode' failure - flammable concentration has to be present, and, electrical failure needs to occur. With a Table that is less than perfect, we would still need a double failure - PPE would have to be less than needed, and, arc flash would have to occur. This would be a pretty low probability and no doubt an acceptable risk. The alternative is to just drive more industry out of the country as the compounding effect of multiple regulations force businesses to close. The Table is a low cost compromise that in most cases will be adequate. The only problem is with it, is that I find it hard to believe that such self proclaimed knowledgable professional would select 2 cycles as a clearing time. They obviously have not performed much breaker testing. I would be hard pressed to find 5 industry EE's that would accept that 'perfect' a condition as being a reasonable norm.


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PostPosted: Fri Jun 19, 2009 9:23 am 
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short-circuit52 wrote:
Running the short circuit and IE numbers for the switchgear bus terminals at the end of the 100' cable run results in a 27.3 kA fault current and 89.6 cal/cm^ at 85% (14.8 kA)Ia. Clearly an "Energized Work Not Permitted" situation.

Joe the Electrican needs to measure the bus voltage. Looking up the NFPA
70E table for "600 volt switchgear voltage testing" it lists cat 2*. Joe dons the required PPE and opens the back of the switchgear cabinet exposing the energized 480 volt bus, and proceeds to drop the uninsulated adjustable wrench shorting the bus bars.

Joe the Electrician should have looked at Note 4 of the 70E table. He would see that the maximum 0.5 sec fault clearing time requirement was not met, so the table is not applicable.


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PostPosted: Fri Jun 19, 2009 10:12 am 
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haze10 wrote:
I find it hard to believe that such self proclaimed knowledgable professional would select 2 cycles as a clearing time. They obviously have not performed much breaker testing. I would be hard pressed to find 5 industry EE's that would accept that 'perfect' a condition as being a reasonable norm.


I have wondered about that myself, how about we get that changed to something more reasonable?

I mostly agree with your whole post, but want to add there are 3 options.

  1. Pay for the study
  2. Use the tables
  3. Use all of those EE's that large industrial plants employ and have them do the study them selves instead of all the meanless jobs engineers in a industrial plant get assigned, changing batteries in radios, overseeing stupid liht bulb replacement programs, figuring out how much money they can save by turning off the lights in the vending machines, I could go on and on :)



I would like to see the tables more real world friendly myself, it seems to me someone dosent want them to be applicable and force certian types of facilities to spend $$ on a study. I am with you on this one Haze.


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PostPosted: Tue Jun 23, 2009 1:22 pm 
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jghrist wrote:
Joe the Electrician should have looked at Note 4 of the 70E table. He would see that the maximum 0.5 sec fault clearing time requirement was not met, so the table is not applicable.


Ha yes.... another typical footer "fine print" situation. First, in my experience training is usually the first to get feel the budget cut ax. I ask you all that have posted on this topic, how many electricians know or understand what a fault clearing cycle is? I think an electrician would be hard pressed to tell you what the FCT is on a a specific panel in his facility. Second, without a short circuit study taking into account the PD trip setting, cables, TCC's, etc. how does Joe the Electrician even know the max FCT is 0.5 seconds? Umm... something about labeling? OSHA mandates companies provide the necessary safety equipment, training and documentation for it's employees. No short circuit study - no FCT assessment...no documentation right? So NFPA 70E gets caught in it's own fishing net. Ok... I agree tables are a first start but they paint with a broad brush attempting to cover every situation. The NFPA 70E's escape clause method is "Let's put a footnote in 5pt type so we can't be held responsible". Its dangerous and plain stupid.


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PostPosted: Tue Jun 23, 2009 3:10 pm 
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Zog wrote:
I have wondered about that myself, how about we get that changed to something more reasonable?

I mostly agree with your whole post, but want to add there are 3 options.

  1. Pay for the study
  2. Use the tables
  3. Use all of those EE's that large industrial plants employ and have them do the study them selves instead of all the meanless jobs engineers in a industrial plant get assigned, changing batteries in radios, overseeing stupid liht bulb replacement programs, figuring out how much money they can save by turning off the lights in the vending machines, I could go on and on :)


I would like to see the tables more real world friendly myself, it seems to me someone dosent want them to be applicable and force certian types of facilities to spend $$ on a study. I am with you on this one Haze.


Less not forget the motion detectors in the bathroom to save KW study....


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PostPosted: Tue Jun 23, 2009 7:07 pm 
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I work for a major 500 company that has four large manufacturing plants in the USA. Between all four plants, there is one EE. I taught arc flash at a 300MW combined cycle generating plant. There were 5 ME's on staff, and not one EE. If you know of a companies that employs a lot of EE''s let me know so I can go there. I'm good at group relamping and motion detectors.

Most facilties do not have the in house expertise to do an arc fault analysis. They would have to hire it at a big expense. The Table method is a more than adequate compromise. OSHA is not design to eliminate all accidents, just reduce them to acceptable levels. This was actually decided in some court case where the accident number had to exceed some representative percentage of the workplace. Maybe someone can comment on this as I don't know the particulars.

I drive to work 30 miles each way every workday. "For example, in 2003 about 45,000 Americans died in motor accidents out of population of 291,000,000. So, according to the National Safety Council this means your one-year odds of dying in a car accident is about one out of 6500. Therefore your lifetime probability (6500 ÷ 78 years life expectancy) of dying in a motor accident are about one in 83."

The table even if not perfect probably reduces my risk of death over my working life to less than my driving life.

All we need is the NFPA to refine the table to something that represents real facilities instead of their text book ideas.


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PostPosted: Wed Jun 24, 2009 6:20 am 
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haze10 wrote:
I work for a major 500 company that has four large manufacturing plants in the USA. Between all four plants, there is one EE. I taught arc flash at a 300MW combined cycle generating plant. There were 5 ME's on staff, and not one EE. If you know of a companies that employs a lot of EE''s let me know so I can go there. I'm good at group relamping and motion detectors.


GM, Ford, Chrysler. And it has worked out great for them. :)


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PostPosted: Wed Jun 24, 2009 6:54 pm 
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I heard Fiat is looking for EE's with lighting reduction and vending machine energy cost saving experience to save a euro in their "new" US auto plants.


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