Codes & Standards – What is the Correct Perspective, Part 1: Permissive Rules verses Prohibitive Rules?

Blog Post created by bryan.holland on Mar 21, 2016

A fundamental goal during the development of a code or standard is to ensure the written word is clear, concise, and easy to interpret.  This is usually achieved by assembling a diverse group of interested professionals with varying perspectives that collectively work together to produce a consensus document.  The process covers all bases, leaves no stone unturned, and foresees any unintended consequences or conflicts.  The result is a nearly perfect document.


In reality, it is impossible to predict every possible scenario, environmental condition, or desired use of an electrical or alarm product by the public.  Once the code or standard has been published and put into use by professionals in the field, there are many occasions were a wide-range of interpretations occur that potentially lead to disagreements between contractors and enforcement officials.  The primary reason for this occurrence is an opposing point of view derived from the individual’s perspective on the purpose and intent of the code or standard in question.    



A common argument in the field that precisely describes this conflict frequently occurs between the contractor and enforcement official during an inspection.  The contractor will ask the inspector to show him in the code where the installation is not permitted.  The inspector in return will ask the contractor to show him in the code where the installation is permitted.  Which person has the correct perspective?  It can be argued that prior to existence of the code or standard, there were no prohibitions.  However, this would mean the code or standard would only need to contain prohibitive rules since everything else is permitted.  This is rarely the case as most codes and standards contain both permissive and prohibitive rules.  



When a code or standard contains both permissive rules and prohibitive rules, it stands to reason that when a method or practice goes unstated; final approval needs to be on a case-by-case basis with consideration of all the specific conditions of the installation. To believe a code or standard is only prohibitive is too restrictive and limits practices that may not have been conceived by the writers at time of publication. To believe a code or standard is only permissive is too liberal and does not allow the code official to use reasonable discretion to reject an installation based on all the facts.



Discretional authority is prevalent in all levels of government and all forms of law, such as statutes or rules. There is a concept in statutory law, which is the manner in which many states adopt building codes and other construction standards that is called, "Expressio unius est exclusio alterius or, "the express mention of one thing excludes all others". The phrase indicates that items not on a list of rules are assumed not to be covered by the statute. When something is mentioned expressly in a statute it leads to the presumption that the things not mentioned are excluded. In short, sometimes rules unstated can be permitted, but sometimes rules unstated are not permitted.



A good example of this concept can be found in the "Uses Permitted" and the "Uses Not Permitted" sections of the Chapter 3 wiring methods in the National Electrical Code.  Take for instance section 330.10 for the permitted uses of Type MC Cable.  The Informational Note following the (12) General Uses and (4) Specific Uses states; "The "Uses Permitted" is not an all-inclusive list." This clearly indicates that other uses of Type MC Cable may be permitted at the discretion of the authority having jurisdiction.  However, this Informational Note does not follow the "Uses Not Permitted" section which indicates the list of prohibited uses is absolute.   



A simple question to ask one’s self when trying to determine if an installation of an electrical or alarm product is compliant with the applicable code or standard is; "will the use of the product in all possible conditions and under all likely scenarios result in a hazard for the user".  If the answer to that question is yes, the installation should be prohibited.  If the answer to that question is no, the installation should be permitted.


The next time you are about to enter into a discussion about the requirements of a code or standard, start by identifying your perspective of the rules and if you believe the rule is permissive or prohibitive.  This will go a long way into helping the other party to understand your point of view and may help to resolve the conflict amicably.



The correct perspective of any code and standard is always the one that allows a free market approach to the use of products while providing practical safeguarding of persons and property from the use of electricity.



In Part 2 of Codes and Standards – What is the Correct Perspective, we will explore the concept of Prescriptive Rules verses Performance Rules.