Is the NEC intended as a design manual?

[Guest]

It has been stated previously and widely accepted that the NEC is not intended as a design manual.

Reading 90.1(C) more carefully there may be some wiggle room there (bold added):

This Code is not intended as a design
specification or an instruction manual for untrained persons.

Depending on how
we read the citation we could reverse it and
interpret it as:

This Code is intended as a design specification or an instruction manual for trained persons[/b]

If in fact the NEC is not a design manual for anybody then it might be more clear to break (C) into two separate statements:

This Code is not intended as a design specification. This code is not intended as an instruction manual for untrained persons

Even that would imply that it is an instruction manual for trained persons.

I'm sure this citation has been beat up pretty good by the CMP and the correlating committee, but as it stands the citation can be interpreted in the field in a variety of ways that may be contrary to the intent of the CMP. I can assume the intent, but I cannot be sure because of the sentence diagram & structure.

[ October 15, 2003, 01:04 PM: Message edited by: awwt ]

 

[charlie b]

Re: Is the NEC intended as a design manual?

Originally posted by awwt:Depending on how we read the citation we could reverse it and interpret it as...

You can?t just reverse it in the manner you suggest, without altering the meaning that the author intended to convey. The rules of logical arguments say that if a statement is true, its contrary need not be true. Witness the following argument: (1) All bears are animals, so therefore (2) All animals are bears.

I agree with you that the wording can be interpreted several ways. I also agree that the intended meaning of the word ?or? in the article is as follows, ?This code is not intended as a design specification (for anyone). This code is not intended as an instruction manual for untrained persons.? But I believe that a properly trained person would have come to realize that the code does not provide any instructions, and would not, therefore, look upon the code as an instruction manual. I conclude that there is no need to change the wording.

 

[Guest]

Re: Is the NEC intended as a design manual?

I also should have added this interpretation:

This Code is not intended as a design
specification [for untrained persons] or an instruction manual for untrained persons.

Since the NEC is a permissive document if it's not prohibited it's permitted. In that context the above interpretation (in my opinion) could be logically reversed if applied to trained persons.

I realize the interpretation is probably wrong according to the intent of the authors, but again it could be an easy mistake to make.

 

[BAHTAH]

Re: Is the NEC intended as a design manual?

Has anyone done a design without using or following the requirements of the NEC? In the handbook the note following 90.1(C) starts as follows: "The NEC is intended for use by capable engineers and electrical contractors in the design and/or installation of electical equipment." The NEC is a design aide for capable designers of electrical installations and used in combination with other information and product application data.

[ October 15, 2003, 01:54 PM: Message edited by: grant ]