EC-1: Article 90 - Part Two

90-4 Enforcement

The NEC can be adopted as a legal requirement for electrical installations by governmental bodies and other inspection departments.

The enforcement of complying with the NEC falls under the authority having jurisdiction. The authority having jurisdiction (AHJ) will be considered the electrical inspector.see fig.1


Generally, the electrical inspector is employed by some government agency and is responsible to an advisory council or board for his or her decisions or rulings.

An inspector's authority and responsibilities include: 

1- Interpretation of the NEC Rules. 

This means that the inspector must have a specific rule upon which to base his/her interpretations. If an inspector rejects your installation, you have the right to know the specific NEC rule that you violated, but naturally, we must be realistic in the recognition that we must often submit to a higher authority.

2- Approval of Equipment and Materials. 

The electrical inspector is the person who decides the approval of equipment. However, if equipment is listed by a qualified electrical testing laboratory (listing agency), its internal wiring does not need to be re-inspected at the time of installation [see 90-7]. see fig.2

in fig.2Listed factory installed internal wiring or the construction of equipment need to be inspected at the time of installation of the equipment except to detect alterations or damage.

3- Warning

Only the inspector can approve equipment [90-4]. He or she can reject the use of any equipment and can approve non-listed equipment. The primary basis of equipment approval by the inspector is listing and labeling by qualified testing laboratories [see 90-7 and 110-2].

4- Waiver of Rules. 

Waiver of specific requirements of the Code or permitting alternate methods. When an installation does not comply with normal NEC rules, the inspector may waive specific requirements of the Code or permit alternate methods. This is permitted only where it is ensured that equivalent electrical safety can be achieved.

5- Waiver of new Code requirements on materials. 

Waiver of new Code requirements. If the 1999 Code requires materials, products, or construction that are not yet available, the inspector may allow materials, products, and construction methods that were acceptable in the 1996 Code.

Note. It takes time for manufacturers to redesign, manufacture, and distribute new products to meet new Code requirements.

6- Ensure that equipment is installed properly [90-7]. 

It is the inspector's responsibility to ensure that the equipment is installed according to the equipment's listed or labeled instructions [see 110-3(b)].

7- Equipment Installation. 

It is the inspector's responsibility to ensure that the electrical equipment is installed to the equipment listing or labeling instructions. The inspector is also responsible for detecting any field modification of equipment. Listed equipment may not be modified in the field without the approval of the listing agency or the electrical inspector [see 90-7, 110-3(b)].

90-5 Mandatory Rules and Explanatory Material 

(a) Mandatory Rules.

Rules that identify actions that are specifically required or prohibited are characterized by the use of the terms "shall" or "shall not."

Section 110-3(b) states that listed or labeled equipment "shall" be installed, used, or both, in accordance with any instructions included in the listing or labeling.

(b) Permissive Rules.

Rules which identify actions that are allowed but not required, such as options or alternative methods are characterized by the use of the terms "shall be permitted" or "shall not be required." A "permissive rule" is often an exception to the general requirement.

Section 250-102(d) states that the equipment bonding jumper can be installed inside or outside of a raceway or enclosure.

(c) Explanatory Material.

Explanatory material, such as references to other standards, references to related Sections of the Code, or information related to a Code rule is included in the form of a Fine Print Note (FPN). Fine Print Notes are informational only and are not to be enforced. Most FPN's contain a reference to another related Code Section.

Summary of Topic
  • The authority having jurisdiction (AHJ) approves the use of products and enforces the requirements of the NEC, but they cannot make-up their own rules. 
  • Product evaluation is done by nationally recognized independent testing laboratories, not the electrical inspector. 
  • Mandatory Code rules use the word shall. 
  • Permissive Rules identify actions that are allowed but not required, such as options or alternative methods. 
  • Explanatory material is contained in the Fine Print Notes (FPNs).