Mandatory and permissive rules

[reyamkram]

In the 2014 NEC 90.5 (A) Mandatory rules state, the use of the terms SHALL or SHALL NOT, are mandatory, 90.5 (B) Permissive rules state, are allowed but not required
by the use of the terms SHELL BE PERMITTED or SHALL NOT BE REQUIRED.

I am a little confused, now 250.64 Grounding Electrode Conductor, states, at a separately derived system SHALL BE installed as specified, OK, is SHALL BE, mandatory or
is it a permissive????

Thank you, for any and all information.

 

[ramsy]

250.64 says all of A through F shall be required, not just one or the other.

An example of "shall be permitted" is found in 90.94, providing more that one way to specify units of measuremet.

 

[david luchini]

Mandatory

 

[reyamkram]

250.64 says all of A through F shall be required, not just one or the other.

An example of "shall be permitted" is found in 90.94, providing more that one way to specify units of measuremet.

Yes, you are correct, I did not want to type the whole paragraph, I am a little confused about the wording,
So, to be a permissive rule, it would state SHALL BE PERMITTED or SHALL NOT BE REQIRED.
and a mandatory rule would state, SHALL BE OR SHALL NOT BE. is that correct. because 90.5 just states, SHALL or SHALL NOT, there is no BE,
grammar was not my best subject in high school, thank you for the replay, and your time.

 

[ramsy]

There's more to pile on permissive-band wagons, perhaps more interesting than where the code SHALL begot or NOT.

Since many state-wide code adoptions follow some years behind the newest code cycle, local AHJ plan checkers can use NEC 90.4 interpretation authority to approve plans based on more permissive revisions of same code section not yet adopted.

This permissive-code shopping can only be provided for competitive bids that make their case to the AHJ.

Since inspectors have no mandate to challenge stamped plans, typically drafted under engineering supervision, plans also remove undesirable-inspector interpretations.

 

[LarryFine]

SHELL BE PERMITTED or SHALL NOT BE REQUIRED. is another way of saying the option is available.

 

[don_resqcapt19]

The NEC is written based on the requirements found in the "NEC Style Manual". The following is from the current version of that manual.

3.1.1 Mandatory Rules. Shall, shall not, and shall not be indicate mandatory rules.
Terms such as is to be, shall be not, and must, whose meanings are less clear, shall not be used.
The terms may or can shall not be used in mandatory rules.
3.1.2 Permissive Rules. Shall be permitted and it shall be permissible indicate allowed
optional or alternate methods. (Note that these are still mandatory language and constitute
rules.) The term may shall only be used where it recognizes a discretionary judgment on the
part of an authority having jurisdiction or in an informational note.