NEC code which mentions arc flash study
- Thread starter adamscb
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- Illinois
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- retired electrician
The NEC does not require arc flash calculations, but in some cases it does require short circuit calculations which are part of the process to determine the arc flash hazard.
David Castor
Senior Member
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- Washington, USA
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- Electrical Engineer
See 110.16 (2020 NEC). As Don said, the NEC does not require an arc-flash study - for any voltage It requires generic labeling and some special labeling for services 1200 A or greater.
relmoudi
New User
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- Buffalo, NY
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- Electrical Engineer
NFPA 70e details arc flash requirements
ron
Senior Member
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- New York, 40.7514,-73.9925
NFPA 70E requires a hazard analysis which leads to an arc flash study, but no jurisdictions that I'm aware of has adopted NFPA70E as a code. 70E typically get invoked when someone gets hurt and OSHA asks why someone was working energized without a hazard analysis.
- Location
- Wisconsin
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- PE (Retired) - Power Systems
- Location
- San Francisco Bay Area, CA, USA
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- Electrical Engineer
OSHA requires that arc flash hazards be identified and labeled with any PPE requirements as part of a REQUIRED program of safe electrical work. OSHA doesn’t specifically require that you use NFPA-70E as the “program” but it is highly recommended. However I have been told by OSHA investigators that if you have a program that lacks the equivalent details of 70E and there is an accident, their scrutiny is increased greatly, often to the point of shutting down a business and sending everyone home until they complete the evaluation. So not following 70E can be a lot more costly than just following it.
mayanees
Senior Member
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- Westminster, MD
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- Electrical Engineer and Master Electrician
From NEC 2023 via NFPA Link there are 11 references to arc flash.
110.16(B)
240.67 & 240.87
... and on and on.
So there's no actual requirement for a Study per se, but labels are required for certain pieces of equipment, and arc flash is addressed for fuses and breakers in the 240.67 and 87 sections.
110.16(B)
240.67 & 240.87
... and on and on.
So there's no actual requirement for a Study per se, but labels are required for certain pieces of equipment, and arc flash is addressed for fuses and breakers in the 240.67 and 87 sections.
mayanees
Senior Member
- Location
- Westminster, MD
- Occupation
- Electrical Engineer and Master Electrician
... unfortunately (for me anyway since that's my line of work) the wording says "field or factory applied" which implies it can just be generic. The only place I can find that actual values are needed is this requirement for fault current availablilty:
110.24 Available Fault Current.
(A) Field Marking.
Service equipment at other than dwelling units shall be legibly marked in the field with the available fault current. The field marking(s) shall include the date the fault-current calculation was performed and be of sufficient durability to withstand the environment involved. The calculation shall be documented and made available to those authorized to design, install, inspect, maintain, or operate the system.
Responsible companies comply with OSHA requirements and OSHA references 70E, so the easiest thing to do is practice per that standard, which says have arc flash labels on panels that may require servicing. But as others have stated, 70E is not mandatory, and the only way you'd end up with it being mandatory is if OSHA shows up at your door because of a fatality.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
But the NEC does not require any Arc Flash Incident Energy value nor a PPE Category, so its labeling requirements do not meet NFPA 70E.
We have two standards, one for installation which must be followed by the EC and a different one for operations which is the responsibility of the owner.
In my opinion two labels are required, the NEC one indicating the hazard and how to avoid it (per ANSI) and the NFPA 70E one an informational label with its values and PPE data.
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