2012 NFPA 70E Labeling 2

[farmape]

Forgive me if these are dumb questions. the 2012 70E requires the Arc Flash Boundary on the label (among other things). This is defined as the distance at which the incident energy equals 5 J/cm^2 (systems >50V). Is there a method to meet this requirement without calculations, understanding the "Table Method" for PPE (and the associated boundaries) exist. At first glance, it appears, to meet labeling 2012 code, the detailed arc flash hazard analysis is pretty much required, unless there are generic distances listed I am not aware of.
2nd dumb question: NEC (NFPA 70), requires only the label warn qualified person of potential arc flash hazards. Why two NFPA documents have different labeling requirements? Does the NFPA 70 "CODE" and NFPA 70E "STANDARD" differentiate the requirements.
Thanks.

 

[jraef]

As I understand it, the basic code says that it must be labeled, the 70E supplement says how it is to be labeled and what that means. I haven't seen the 2012 yet so I can't comment on that part.

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[jghrist]

If you are using the tables instead of calculating incident energies and arc flash boundaries, use the HRC categories and arc flash boundaries listed in the tables for the labels.

The NEC is a legally required code in most states, but NFPA 70E is only referenced in the NEC and OSHA. The NEC reference to NFPA 70E is in an informational note, so is not an enforceable requirement. The NEC leaves the details of the labeling up to NFPA 70E. Perhaps the reasoning is that the NEC is an installation standard and the labels may need to be revised after the initial installation if conditions change.

 

[farmape]

That is a great explanation, I never heard it or thought it described as simply as that. Thanks. A question I always get is "What are the labeling requirements" ... which results the NEC or the 70E.

 

[farmape]

Both thank you. I agree with yes the installation may change requiring labeling update, and, like you said, the NEC is an installation code. I never thought of that either.
I only have the 2012 70E in front of me, but I cannot see where arc flash boundaries are listed. Where they removed?

 

[jghrist]

The boundaries are now in the first part of each equipment type in Table 130.7(C)(15)(a). The fault current and clearing time requirements were also move from notes to the table body.