Which label and why do you specify (as a design engineer), recommend (as a consultant) or require (as an owner/client or AHJ)? Do you have any specific instances where one has been enforced over the other?

As a follow-up to those who are proponents of the NFPA 70E methods how do you address new installations/panels. Most manufacturers will ship you panels labeled per NFPA 70, Do you specifically specify/request no labeling (will any actually do this), perform a study and field label or scrape all the labels once the arrive and then field label?

I am just trying to see what is standard practice and/or being in-forced (owners or AHJ).

Thanks!!

Manufacturers balk heavily at the idea of labeling anything for 70E. NEC (NFPA 70) makes it very clear that this is a FIELD APPLIED label. The one exception is that at least at one time at least one vendor of lighting panels had a label that I recall said something to the effect of there being no arc flash hazard as long as the dead front cover was in place but I haven't seen this in years. Similarly there are certainly some cases where labeling COULD exist. For instance on industrial control panels where the vendor establishes maximum short circuit (via the SCCR rating) it could definitely be possible to label it but I've never seen anyone do this.

IF the vendor is commissioned to do the arc flash study then by all means they may indeed do it if the customer pays for it. With a large servo drive system that I was project manager over a couple years ago ($12.5 MM just for the electrical on this project), the vendor did the arc flash study and provided quite a bit of labeling of their own. It was also one of the areas that it outside the purview of OSHA and thus outside the NRTL requirement so UL listing wasn't required either.

There is no such thing as a "standard" design. The available power system analysis software (ETAP, SKM, EasyPower) has built in label templates. Similarly if you buy a printer such as one from Brady that does "arc flash labels" it typically comes with label templates in a free software program. And you can pretty quickly make your own.

OSHA as well as NEC and NFPA 70E specify using ANSI Z535 as the standard for labels. This standard was "GHS"ified several years ago. Note that most Brady labels are NOT compliant with the current ANSI Z535 and you have to search for ones that are. Note also that nearly every single label where the text is spelled out in NEC is not compliant with ANSI Z535 either. It contains quite a bit of detail but suffice to say that all arc flash labels must contain the signal word "WARNING" in orange and the very generic exclamation mark triangle symbol to be Z535 (and GHS) compliant. The old circles and other shapes around the signal word are gone in the current Z535 standard and use of the word DANGER for arc flash hazards is definitely prohibited in ANSI Z535 despite the fact that lots of software incorrectly uses it for anything over 40 cal/cm2. Beyond that the contents are pretty much free form but here are some suggestions:
1. Use the PPE level (1, 2, 3, 4) ONLY if using tables from 70E. Otherwise ONLY use the incident energy value, rounded off to a whole number (unless it's something like <1.2 cal/cm2). Do not put both values on a label. This is a requirement in 70E-2015. It may go away in the 2018 edition but right now it's here to stay.
2. Include the arc flash boundary on the label.
3. Not required but to keep everything in one place most labels also include the system voltage and shock boundaries (restricted and limited) on the label as well.
4. Not required but some labels have specific PPE on them. This has changed a couple times due to new information and changes to the standards in the last 10-15 years, and there are some user-defined options here as well which mean I recommend leaving the specific PPE off the label entirely for future-proofing reasons.

Sometimes there are other optional things such as if the incident energy changes drastically depending on use of a maintenance switch or based on arrangement of generators or feeder breaker configuration. Furthermore with arc flash some areas pretty much require a double label such as transformer termination enclosures that may have multiple voltages present.

Another suggestion is to consider whether to print labels as needed on demand, or to develop some system of rounding/bracketing where only a minimum number of labels can be printed ahead of time and stocked instead. The former seems like a better system but every time I have to use the printer I spend most of my time setting it up and getting it working again and only a small amount of time actually printing labels. Also the labels themselves fade even with the "outdoor grade" ones in short order. The only effective solution is to use a UV resistant overlay (transparent film) in which case I've found that an ink jet printed sheet of paper works just as well as the high grade vinyl thermal transfer label. So if you can reduce the total number of labels down to a manageable level then they can be printed at a print shop en masse relatively inexpensively and then stocked and used as needed without all the previously mentioned disadvantages of the print-on-demand approach.

If you do buy a printer, find out who the real vendor is for a certain thermal transfer printer on the market that has an orange colored body. This particular printer is a standard printer made by a lesser known company that has been modified with an RFID reader hidden in the housing. All the print materials for this printer have a 300-400% markup and they are standard materials except that they have an RFID tag stuffed inside the cardboard tube in the middle of the roll. On top of the crazy pricing the RFID board is not very reliable and results in a very frustrating experience every time I went to use their printer. Moral of the story: download the software (free) if you want it but buy the printer from the OEM and you can buy transfer ribbons and media from anyone without the ridiculous markup.

The latest version of NEC (NFPA 70-2014) by the way is completely noncompliant in another way. It has requirements that mandate up to a half dozen or so warning labels on some equipment, especially main breakers in double ended substations. They went label crazy in this edition. ANSI Z535 specifically prohbits more than 3 warning labels for a given task and NEC violates it despite requiring compliance with ANSI Z535 in NEC!

All this being said a lot of research has gone into labels that shows that for the most part all the warning labels are not very effective and that the specific formatting is not really all that critical in the first place...A simple black-and-white lettered sign is just as effective as the full ANSI Z535 requirement.

So I suggest if you truly want to be compliant, get a copy of the ANSI Z535 set and read it. Get a copy of 70E and read the short section on label requirements there and look at their sample label. Then make your own by modifying (mostly, purging unnecessary details) an existing template from your choice of software programs that you will be using for labels whether you use it to print and send labels to a print shop or print your own.

PaulEngr,

Thanks for the response and plethora of information!


I was not referring to a standard design as much as I am looking to see what the standard practices are and what is actually being in-forced.

I can look at this from two different prospectives.

Ethically, professionally and as l promoter of safety and wanting to make sure everyone goes home safely at the end of the day. Provide the correct and enough information along with proper training to allow people to make an informed decision to create a safe working condition. The two go hand in hand, you can not have just one to make the correct decision.

So my, question really is. “Is there a fine line� between the two NFPA 70 and NFPA 70E? Our clients (Christian Schools and Churches) are working on very tight budgets, which depend heavily on giving/donations. In the the 14 years I have been associated with our operations I can not recall one instance we have ever been asked or required to provide NFPA 70E labeling. I understand that any reputable electrical contractor that would be working at these facilities, during construction or post construction (maintenance, upgrades, repairs, etc.) would most likely be working from the NFPA 70E guidelines and performing hazard risk assents. Is the information we provide on a One-Line and Panel Schedules as part of the initial design (Amp Ratings, AIC Ratings, Available Fault Current, Connect Load, etc.) enough or even available during these post construction activities?

So, what is really required vs standard practice? I have a hard time telling our clients they need to spend more money on a study that is or is not really required??? But, if they study and proper training does create a safer work environment and releases them of some liabilities (again only with correct information and training), I am willing to request/require the extra cost for safety.

Thanks Again!!

I've had this question before as well, related to similar "low dollar" industries, residential, commercial, etc.

First off, all that NFPA 70 (NEC) requires is a warning, something like this:

http://ecmweb.com/ops_maintenance/101ecmSSfig1.gif

The reference to 70E in NEC is in an informational note (also known as a fine print note in older versions). This means that it is there for clarity or information only. It is NOT enforceable. So unlike say ANSI Z535 which is referenced and mandated by OSHA, 70E is 100% voluntary. The warning labels are not voluntary, but 70E is voluntary. NEC is not necessarily mandatory but it is required by state law in all 50 states in the U.S. unlike say Canadian CEC Part I which is the Canadian equivalent and is mandatory by federal Canadian law in that country. This meets Code as far as NEC is concerned and it could theoretically meet OSHA requirements depending on how it is implemented.

The next concern is how does OSHA view things. In this case we have to consider two cases. The first is equipment and industries that are utilities or have equipment similar to utilities such as a cogeneration system, a solar farm, etc. These fall under OSHA 1910.269 which mandates an arc flash study. The second case is everyone else. In this case there are no mandatory requirements except the general duty clause that mandates that employers protect their employees against known hazards. Although this sounds very vague, OSHA has issued citations for arc flash going back as far as 2006.

Next we move on to the practical issue...how to actually do something about this. Based on the use case, there are no qualified personnel on staff...no staff electrician, engineer, etc. So even if an arc flash study was done, there's nobody to train beyond the basics for nonelectricians...nobody qualified to use shock protection nor arc flash protection. So putting labels on and maintaining them doesn't do anyone any good at all. In this case, the general warning sticker actually does exactly what it's supposed to do. It goes something like this:
1. If it doesn't look right to you, go get help from someone qualified, especially if it has soot marks, water coming out of it, big holes in it, doors blown off, or wiring hanging down or exposed.
2. If it tripped, don't reset it. Circuit breakers have been known to explode when they are reset. Get someone qualified to investigate why a circuit breaker tripped and make an necessary repairs. A little inconvenience is better than a lifelong injury.
3. Above all stay away. Stay at least 3 feet away from damaged or suspect electrical equipment, and at least 10 feet from free wiring such as overhead power lines.

A reputable contract electrical company will run into this situation all the time. Construction sites are simply not going to have a complete arc flash study done for the temporary power that exists on most sites. Equipment gets moved around constantly and the study if one exists won't get updated. And some locations such as those under discussion simply aren't going to have an arc flash study on hand and most never will. This means that in this case we fall back to the tables in 70E because that's all that is available. And the personnel using those tables are the qualified electricians doing the work, not the clergy or other personnel on site that are based off staying out of the area unless invited and escorted in.

A power system study can still be done if desired. As an example of what happens when you skip getting an engineer involved, I did one for a large campground not too long ago that was rather unusual in terms of its power distribution due to the size of the building on site and the fact that the architect and utility (and REA), and fire marshal involved decided to distribute everything from one huge transformer at 208/120 and didn't think twice about the cost of multiple parallel feeders (I think there were something like 4 sets of 350 MCM feeders). The contractor had convinced them that since it's 208/120, there would be no arc flash hazard which was definitely not the case by the time they got through sizing the transformer to a ridiculous size. The utility put primary fuse cutouts on the transformer to protect their system but that was the only protection for the entire system until we get to the various subpanels distributing power throughout the site. It took about 6 hours including inspections to put it all together and a meeting to walk through as-is, mitigated version, and Code requirements, so with a rate of around $150/hour, it would have run $900 for the study. The fire marshal in the area tried to argue that since a fire pump was fed from this disconnect that no protection at all was allowed (a misread of NEC requirements). The only mitigation recommendation I had was to change the disconnects at the pole for fused disconnects on the secondary side of the transformer upstream of the other EXISTING disconnects and to change the fire pump feed to a fused disconnect as well (NEC requirement). The disconnects got marked with all the nasty arc flash warning stickers while the downstream disconnects did not receive such treatment since the upstream fuses mitigated any arc flash hazard.

This was a rather extreme case and one that the tables in 70E are not really appropriate for handling. But it gives you some idea of a worst case scenario.

Not an endorsement but read here. Also look up other cases and you can get a feel for the consequences. Usually aftermath of an incident)

http://www.e-hazard.com/blog/march-2000 ... arc-flash/

Thanks and once again very informative!



Please confirm are you saying that if a Church or Private School has Solar Panels, by OSHA Regulations they are Required to have an Arc Flash Study?

We do have clients that have Solar, as it helps supplement costs, construction incentives utility payback, etc.

OK, let me whip out my crystal ball and read the mind of a bureaucrat. It's very cloudy. Nope, not getting anything here.

If you follow the letter of the regulations, here is what I know. Nothing follows a SIC Code or anything easy like that. A cogeneration facility follows 1910.269 for generation, transmission, and distribution equipment even if it is in an industrial or commercial site but any part of a utility that is "utilization" equipment follows Subchapter S. And if the equipment is "mixed use", it follows BOTH 1910.269 and Subchapter S simultaneously. There is an index in 1910269 Annex A that points to the various regulations that apply for the mixed situation. And many states recognize that equipment that falls under 1910.269 also follows NESC (IEEE C2) instead of NEC (NFPA 70) but the definitions in both of those codes are not exactly in perfect harmony with each other. This also means that sometimes we're following UL and sometimes ANSI, depending on whether it is pure "generation, transmission, and distribution", or mixed or utilization only.

Remember...small scale wind and/or solar that is utility-interactive and generates any significant amount of power is a relatively new thing. Until a few years ago it made zero economic sense. The regulations that did exist were intended for things like large paper mills that supplied about a third of their own power needs from burning waste wood byproducts. Right now nobody is really sure exactly how to regulate it. Even DC arc flash is still relatively in its infancy. We don't have anything on the scale of the IEEE 1584 database for DC arc flashes and so far the models that have been developed are off by a factor that is as low as 140%. So we're not there yet.

As a practical matter after having had discussions with regulators in various industries and various "fringe" cases that are decidedly "not by the book" what I found is that if you choose a set of regulations to follow and you make a plausible case for doing so, chances are that the regulators will just follow your lead and apply the same rules. Here are some examples:
1. In New Jersey, the local Code official decided to apply "occupancy permit" rules to construction in a plant that had been an active site for 200 years and had never applied for a permit. Basically I was replacing a truck scale and he wanted me to pull permits for the scale because it was right out by the road. I'm not exactly sure what "occupancy" means for a truck scale, and industrial plants are almost always essentially continuously under construction. Worse still after giving him a tour of the plant (an iron foundry) he was pretty much at a loss as to how to do inspections, recognizing that it was much more than a house or even a commercial warehouse. So we came to a gentleman's agreement that I'd pull permits for anything clearly visible from the road and perhaps show up to their local meetings once in a while, and invite them in on projects that may interest them.
2. An OSHA official concerned about an afterburner system and how it operated after a sister plant blew theirs up. This got a little hairy because the two Codes (NFPA 85 and 86) require a certain number of exchanges of outside air, but an afterburner system is a flaring system...it is there specifically to burn off fuel that is always present. We eventually came up with an engineering solution.
3. Open pit non-coal mine electrical regulations can fit on about 2 typewritten double spaced pages (I know because I typed them up once). Most mines apply NEC as an engineering standard to fill in the gaps in the regulation, and most mining inspectors also use NEC as a standard when their own regulations are not detailed enough.
4. Lots of issues with a local Kentucky state inspector about dust emissions that was caught up in a local turf battle between federal EPA regions 3 and 4. We got him to agree to use Method 9 for determining whether we were in compliance with fugitive dust emissions, and then invalidated all his attempts at taking observations because of the constraints of method 9 (need the sun to your back and a clear view of blue sky in the background, not staring at the side of a building).