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NEC vs ANSI / UL conflict

NEC vs ANSI / UL conflict

NEC vs ANSI / UL conflict

I have always approached the issue of code conflicts from the standpoint that the NEC is related to the installation and connection of equipment, while the construction and design is covered by other standards such as ANSI and UL. Apparently, this line has been blurred by the NFPA some time ago with the issuance of article 430-97 of the NEC. Sub-article b) specifically describes the bus bar phasing arrangements. Here are my questions;

1) Does anyone know of a provision in the NEC, which states that ANSI compliance or UL listing takes precedence over NEC design requirements such as this? I have always acted as such, but being confronted with this situation has shaken my faith in that and I can't find a reference to back me up.

2) Does anyone know of a reference to article 430 being relevant to low voltage system (600V and below) only? Someone else brought this up and I have always ASSUMED so (and yes I know what happens when I ASS-U-ME), but now I am put to task and can't find it!

3) Likewise any provision to allow granfathering of existing UL listed designs? The 5kV equipment I am using has the main horizontal bus bars oriented with phase A in the back; technically in violation of article 430-97, yet the equipment was UL listed this way. I have a 1987 codebook where this article does not exist, and a 1996 book where it does. Must have happened between 1988 and 1995, but I must have killed off the brain cells devoted to those years.

Any help would be greatly appreciated.

I am cross posting this to maximize my chances of getting responses.

Subvert the dominant paradigm... Think first, then act!

RE: NEC vs ANSI / UL conflict

Phase arrangement is an installation issue. Unless the MCC has a built in generator, phases must be brought in from outside. 430-97b describes this connection.

430 clearly doesn't apply only to low voltage, since 430X specifically addresses over 600 volts, and other parts of 430 list specific exceptions for over 600V.

RE: NEC vs ANSI / UL conflict

Article 80.9 in NEC covers existing installations as well as alterations and modifications.  Existing facilities are not required to comply with current Code (unless required by the AHJ).  

Article 430 only covers motor control centers, but I am sure you already know that.

As for conflicts with UL, it might be simplest to call UL and inquire.  UL had a member on the Code Making Panel 11, at least for the 2002 Code.  

Interesting problem - let us know what you find out.

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