NEC 2026 new arc flash hazard markings required

[jim dungar]

AHJs:

Are now expected to review arc-flash labels

They are expected to see if a label exists. They are not required to personally verify the values on the label. Just like they are not required to perform load calculations and wire sizing.

NEC 2026 has functionally mandated the use of IEEE 1584, and IEEE 1584 is only realistically accessible through licensed software or specialized consultants.

This point was raised prior to the IEEE 2018 version being released. Have you looked at the old discussions on Arc Flash sites like the arcflashforum on brainfiller.com?

 

[MyCleveland]

They are expected to see if a label exists. They are not required to personally verify the values on the label. Just like they are not required to perform load calculations and wire sizing.

This point was raised prior to the IEEE 2018 version being released. Have you looked at the old discussions on Arc Flash sites like the arcflashforum on brainfiller.com?

They can ask to see the calcs.

I have not looked for this discussion on your two references…I will now.
I did communicate with JP/brain filler about whether he has generated training in a DVD format as he did with the 2002 version…no, have to sign up for his full class to access.

 

[Aespinosa]

Funny timing on this discussion — I just posted about my experience implementing IEEE 1584-2018 from scratch and validating against 105,000+ test cases. The "only accessible through proprietary software" point really hit home. It shouldn't be this way.

Validated against 105,000+ test cases to get IEEE 1584-2018 right — here's what took me 3 weeks to figure out

So I went a little overboard. I decided to implement IEEE 1584-2018 from scratch and validate it properly. Not just against the handful of examples in the standard — I'm talking about the full IEEE test vector dataset. 105,615 cases. Every combination of voltage, current, electrode...

forums.mikeholt.com

 

[Aespinosa]

Digging deeper about possibly building a tool for calculations.

Some interesting ChatGpt comments...

This Crosses an Important Line (Quietly)

You’re pointing out something historically rare in U.S. codes:

A code compliance requirement whose only feasible path is through licensed proprietary intermediaries.

Most codes:

Can be complied with via education and judgment

Allow conservative bounding

Are implementable with public math

Arc-flash is different.

Why AHJs Are Especially Exposed

AHJs:

Are now expected to review arc-flash labels

Do not have:

IEEE 1584 or SKM / ETAP

Time or budget

So enforcement becomes:

“Does this look like it came from a known tool?”

That is tool-credibility enforcement, not engineering enforcement.

Bottom Line

Conclusion is accurate:

NEC 2026 has functionally mandated the use of IEEE 1584, and IEEE 1584 is only realistically accessible through licensed software or specialized consultants.

That is not how most safety requirements work — and it deserves scrutiny.

The Uncomfortable Truth

Until:

IEEE releases a reference implementation

NFPA hosts a public annex

Or government funds open safety data

…this situation will persist.

Funny timing on this discussion — I just posted about my experience implementing IEEE 1584-2018 from scratch and validating against 105,000+ test cases. The "only accessible through proprietary software" point really hit home. It shouldn't be this way.

Validated against 105,000+ test cases to get IEEE 1584-2018 right — here's what took me 3 weeks to figure out

So I went a little overboard. I decided to implement IEEE 1584-2018 from scratch and validate it properly. Not just against the handful of examples in the standard — I'm talking about the full IEEE test vector dataset. 105,615 cases. Every combination of voltage, current, electrode...

forums.mikeholt.com