NEC Mistake

Maxwell'sLaw

Member
Location
New York City
Occupation
New construction field electrician
Greetings, hope your doing well.
The reason I am contacting you:

I just saw the post on the topic of the "Mistake in the NEC" that Steven120volts recently put up; here's the link in case you want to review it:


Whilst I understand clearly what he is articulating, and while I have much respect for Steven120volts, as well as AnGry Sparky, and Paul Abernathy, in staying true to my philosophical tagline : "I am a seven footer chopped in half of a latino hillbilly, who's thirst for knowledge far exceeds my limitations",
I am concerned with how do we reconcile the wording of that particular article with the actual laws of physics regarding balanced forces and ampacity thresholds between the receptacle(s) as a unit which serves as a power supply bridge for energizing equipment, the conductors, and the OCPD?

I'd greatly appreciate it if you would kindly grace me with a few minutes or your time to enlighten me on this. In case you want to have a live conversation with me regarding this seemingly contradictory topic.

In the meantime, may Lord Almighty continue to bless you richly and immensely in countless ways each and every day.
 
Nice video thanks for sharing, its not a mistake, section 210.21 deals with the minimum rating, its the floor section 406.4(E) deals with the interchangeability issue. It was inconsistent to have one rule for single receptacles, which always existed, and another rule for duplex.
I once ran across a NEMA 10-30 receptacle that had been installed on a 2-pole 15 on 14/3 wire in a basement. Since there were no other NEMA 14-30 receptacles in the building , and nothing plugged in no NEC violation existed. If someone plugged a 5500W clothes dryer in there would be a violation of the various articles that cover branch circuit load calculations, as you'd violate the load calc how 210.11, 220.10, 210.22, 210.18 etc.. interplay
I have also herd an argument that if a NEMA 14-50 is used for a 40A branch circuit it cannot be used for a 50A branch circuit.
 
This is nothing more than a coordination issue between code sections that was not caught at the time the change to 210.21(B)(3) was made. It can be corrected by changing the reference in 406.12(A) [2026 code, 406.4(A) in the 2023 code]. The current reference is to Table 210.21(B)(3), but should have been changed to Section 210.21(B)(3) to avoid the conflict.
The installation of single receptacles having a rating greater than the rating of the branch circuit has been permitted for a very long time. The 2023 change in 210.21(B)(3) just applied that same rule to multiple receptacles on a branch circuit.
There is no hazard in either case as the branch circuit OCPD is sized to protect the circuit conductors and will open where the load exceeds what is permitted by the breaker time current curve.
 
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