I have searched old posts but still want to know what everyone is doing. We have had an arc flash analysis done and the guy that did our analysis wanted to know how many labels we wanted for Category 0. I told him that due to the requirement of 130.3(C) "Equipment shall be field marked with a label containing the available incident energy or required level of PPE" that we would need a label for every panel that the mechanics would get into. The procedure that was going to be put in place was to go up to the panel during a maintenance call and read the required ppe off the label and then go get the ppe (perform appropriate visual inspections....inflate gloves, etc) and then go back and perform the troubleshooting. We were told that most people do not label all of there equipment panels if it is going to be a category 0 (though there was no specification of which category 0 panels to label and which weren't required to label) All of our equipment that was under 60 amp feeds (480V) was considered to be a category 0. How is everyone labeling there panels...and is it allowable to not put labels on panels that are category 0? Thanks for the info.

Who says those are catagory 0? That is a major problem IMO.

I wouldn't argue with you. I've never done calculations nor do I have the software to do it. I asked on this forum about a week ago how people felt about that issue. I posed that question to the consultant of how it was acceptable to say it would be a Cat 0 and I was told that it has never been documented any injury resulting from a circuit with that limited current, and that it would not sustain an arc. I was also told that the runs would be reviewed but not calculated...I know the lengths of those runs were never told to the consultant. There could be runs up to 300' with those size breakers feeding the panels out on the floor and that is what had me concerned with whether or not the cat 0 would be an accurate rating....actually I think you (Zog) may have said "sounds like the low bidder" I actually dont think they got quotes from other consultants......either way I still want the employees under me to be protected if there was an AF incident.

What is your oppinion about having a label on every panel at each machine?

The same as yours - 130.3(C) "Equipment shall be field marked with a label containing the available incident energy or required level of PPE"

But the HRC 0 for 480V equipment, even if only 60A shows me a gross misunderstanding by the person that is doing the analysis.

I agree with Zog. You should check the credentials of your AF consultant.

I agree, a label is still required even for HRC 0 panels. HRC 0 is low hazard, not zero hazard and PPE is still required (nonmelting, long sleeved clothing). I also do not believe you can simply classify equipment as HRC 0 just because it is 60A, 480V.

In addition to 70E 130.3, the NEC says in article 110.16, "Electrical equipment, such as switchboards, panelboards, industrial control panels, meter socket enclosures and motor control centers that are in other than dwelling occupancies, and are likely to require examination, adjustment, servicing, or maintenance while energized, shall be field marked to warn qualified persons of potential electric arc flash hazards. The marking shall be located so as to be clearly visible to qualified persons before examination, adjustment, servicing, or maintenance of the equipment." Simply de-energizing the equipment before servicing will not get you around this requirement either since an electrically safe work condition cannot be established until it has been properly verified with a meter (NFPA-70E 120.1).

The exceptions to not performing an arc flash hazard analysis are found in NFPA-70E 130.3 and say all of the following conditions (1-3) listed below must exist, or you must follow NFPA-70E T130.7(C)(9) which assigns an HRC based on voltage and task providing you meet the maximum short circuit current and clearing times specified in the table notes.
(1) the circuit is rated 240V or less
(2) the circuit is supplied by one transformer
(3) the transformer supplying the circuit is rated less than 125kVA

If conditions 1-3 exist and you don't do an analysis, do you label the equipment Category 0?

If you use Table 130.7(C)(9), what do you put on the label? Not all tasks are Category 0.

When conditions 1 through 3 (above) apply, I use a label from SKM's label style selection called - Generic Label 1 (4X6) - Secondary Voltage < 240V

I would think the other software packages have something similar.

Labeling the Panel When Applying the Exception



We do not use the table. I suppose perhaps you could post a copy of just the section on Panelboards or Other Equipment Rated 240V and Below on the actual panel along with a generic AF warning label.

When conditions 1-3 exist we could not just use a generic label simply stating "Warning AF Hazard" since we still are required to specify PPE or incident energy and also wanted boundaries posted for both AF and shock protection. I forced the AF Hazard for that particular panel to 1.1 cal/cm so that it falls into HRC 0 and the AF boundary then defaults to 4 ft. since this values is forced, not calculated.

@ amphead - I like the SKM generic label; not sure EasyPower has that option but I will look.