Arc Flash requirement by OSHA 1

[cuky2000]

Is arc flash calculation and labels required by OSHA?
Are electrical utility exempt of performing arc flash study?

 

[xnuke]

Yes, and no. Link

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[HamburgerHelper]

I came across a paper once that was a series of solutions the writer came across by interviewing people in industry about arc flash mitigations. Most were what you expected, common mitigations. The last one was a situation were the energies were above 80 or 100 cal/cm^2. At those energies, someone might get killed from the arc blast no matter what they had on. It is like a bomb going off when copper expand 20,000 times its volume when it turns into a plasma. So, the guy in charge hired a firm to study the situation and come up with a solution. He didn't like any of the solutions. Too expensive. So, he got utility workers who passed under an exeption to do the work live work for them. Why anyone would work for that guy or the utility is beyond me. As cheap and easy as arc flash studies and solutions are in comparison to the cost if someone was maimed or killed, I don't understand how even a bean counter can justify unsafe conditions.

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If you can't explain it to a six year old, you don't understand it yourself.

 

[wbd]

Arc Flash calculation and labels are not required by OSHA for General Industry. OSHA can cite for not having the proper PPE for protecting employees from known hazards and arc flash is a known hazards. So to provide the proper PPE, either a study needs to be done or the table in NFPA 70E has to used adhering to the parameters of fault current and clearing time.

OSHA does require utility companies to perform a reasonable estimate of incident energy and they list a table of acceptable methodologies to achieve that. OSHA also does not require labels and frowns on it as OSHA believes that the incident energy should be known prior to the employee arriving at the job site. OSHA believes that this is best accomplished by a tailboard.

The last one was a situation were the energies were above 80 or 100 cal/cm^2. At those energies, someone might get killed from the arc blast no matter what they had on. It is like a bomb going off when copper expand 20,000 times its volume when it turns into a plasma.

This is an outgoing misconception of arc flash. The incident energy is related to the time the arc exists. For the above example cited, what was the time to achieve 80 cal/cm2? Was it 0.25 sec or 1000 sec? Typically there is a reasonable cutoff of 2 sec. Also, what was the fault current used? Was it available fault or fault current from an infinite bus? There are many reasons that the 80 cal/cm2 may not be realistic.

The other notion is that the consensus is that the blast issue is not realistic. There have been cases of large IE but no blast that would slam a person against a wall

 

[dpc]

I'd say NO and NO. That doesn't mean it's OK to ignore arc-flash safety.

OSHA has specific regulations covering electric utilities. These regulations were revised in 2015 to require arc-flash PPE be provided and used by utilities. OSHA "General Duty" clause has been used to fine companies of all types after arc-flash events if no PPE was provided. If someone is injured in a arc-flash accident and no PPE was worn, if OSHA gets involved, they may fine the company. OSHA considers NFPA 70E the accepted "standard" of care for electrical safety, but do not enforce compliance with 70E.

Utilities are "exempt" from the requirements of NFPA 70E. But NFPA 70E is not a legal requirement for anyone anyway. Utilities are not exempt from OSHA, obviously.

Rather than trying to find excuses for not complying with NFPA 70E, companies would be well-advised to work out a reasonable electrical safety program that includes arc-flash protection. After 15 years, we know the PPE is effective IF WORN. It's frustrating to continue to have workers suffering serious burn injuries that are completely preventable.

 

[cranky108]

I agree to a point. That point is some utilities are government enterprises and may not fall under OSHA. We could argue they should be, but that something different.

That said, the same utilities can have OSHA inspectors jailed for entering the properties.

So at that point NFPA 70E may not apply. But the same utility can say they follow the NESC standard.

 

[SeaBow]

We are required to follow NESC as a Public Utility.

NESC 410A3: The employer shall unsure that an assessment is performed to determine potential exposure to an electric arc for employees show work on or near energized lines, parts, or equipment.

We have done these calcs as well as giving our employees some rules of thumb for equipment and locations. It is also super important that the worker understand that even 2 Cal's will burn you. Best to rule on the side of caution with AF. There is a nice video out there of a 1.5 Cal exposure that we shared with our workers.
Link

 

[dpc]

SeaBow: This varies by state in the US. It's a legal requirement in some states, but not others.

 

[SeaBow]

dpc: Good catch. Absolutely! I should have added "in our State".

 

[jraef]

But what OSHA does require is that ALL employers must provide for a safe work environment and with respect to electrical systems, they MUST have an Electrical Safe Work Program that is periodically reviewed and to which employees are periodically tested (I use periodically because there have been changes to the periods and I can't remember them right now). OSHA does not specifically SAY that the program must be NFPA-70E, but it CLEARLY implies it by using it as the only stated example of one.

My company provides Arc Flash Prevention services and Arc Resistant Equipment, so I get involved in this question on a semi-regular basis, probably 6-8 times per year. For people that I have been involved with who have had Arc Flash incidents in their facilities where OSHA inspectors became involved, the sequence tends to go like this;

The inspector(s) first meet with company management, asking to see a copy of their Electrical Safe Work Program. If the answer is "Our what?", the conversation becomes almost immediately hostile and if they cannot produce it very very quickly, OSHA can IMMEDIATELY shut down the entire facility and send everyone home! In addition if the accident cause can be traced to a poor procedural issue that should not have been allowed, the company managers and all supervisors for the area or process where the accident took place can be JAILED. I have not come across anyone who has had that happen, but I attended a seminar by retired OSHA inspectors who confirmed that they have "made examples" of managers at times. The operative issues are that 1) the document is REQUIRED BY LAW of ALL employers, whether or not they actually do electrical work, 2) ignorance of the law is not an excuse, and 3) it cannot be subrogated to off-site contractors, meaning you cannot say "Well, all of our electrical work is done by XYZ Contracting, so they are responsible for it." You can have that contractor provide you with a copy of their program and you can adopt it as your own, but you must still have one and have knowledge of it. These issues have almost universally come as a shock to all of the people I have encountered who have gone through this.

Conversely, the two I met last year who had in fact adopted NFPA-70E reported that the conversation with management was basically very short once that was revealed, so the inspectors move on to the details of the accident to look for what went wrong or what in the procedure, if anything, was not followed.

Utilities have different standards for THEIR electrical work practice programs, but as employers, they are absolutely required to have one, and I would be shocked (pun intended) if any one of them did not. But it does not have to follow NFPA-70E, their standards must, by necessity, be very different.

As to the anecdote about hiring utility workers to get around the rules. The rules are not about the workers, they are about the employers. That guy could have been jailed had anything gone wrong.


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