This article takes a closer look at gray areas in the National Electrical Code and how to successfully navigate them. The NEC is revised on a three-year development cycle, and each revision is suitable for adoption into law by federal, state and other local adopting jurisdictions. Once it becomes the adopted, compliance becomes mandatory. The NEC contains minimum requirements for essentially safe electrical installations.

The NEC is the playbook for the electrical construction industry, providing essential information directly related to safe engineering, designs and system installation in the field. Contractors must follow it to the letter. 

Who has the responsibility?

Jurisdictions lagging on the adoption process are often missing out on crucial rules for the latest technology. This can be a disadvantage to Code enforcement officials, especially if the adopted NEC in a jurisdiction is several cycles behind. That is a whole different topic for another discussion.

As provided in Section 90.4, the authority having jurisdiction (AHJ) has the responsibility of enforcing the Code, interpreting the rules and issuing approvals. The AHJ can also grant special permission when necessary, which must be in writing based on the defined term “special permission.” 

The AHJ has a serious responsibility that often involves exercising sound judgment—specifically when it comes to navigating those “gray areas” of the Code. It contains many black-and-white mandatory requirements, some exceptions to the rules and some permissive requirements, as outlined in Section 90.5. But sometimes an installation or design does not fit within the clear guard rails. This is where the training and experience of contractors, designers, inspectors and sometimes owners gets involved. Ultimately, the inspector is the approving authority, so if a gray area is encountered, it’s important to communicate with them.

Some gray areas explained

Below are a few gray areas that can help you understand this space when applying the NEC to a certain installation.

The first example is found in Section 230.70(A)(1), which indicates that the service disconnecting means shall be installed at a readily accessible location (a defined term) either outside the building or structure or inside nearest to the point of entrance of the service conductors. This rule is one of those with a built-in hierarchy: the first effort should be to install the service disconnect outside, but the option of an inside location is provided within the same rule. This gives the user the prerogative of locations, but in either location, the readily accessible requirement must be met.

The gray area here is introduced by the word “nearest,” which is nonspecific. There is no distance measurement for near because electric services come in many capacities and sizes. What could be accomplished very easily for a 100A service is rather difficult for a service at 4,000A. Obviously, more distance may be necessary for larger service disconnecting means and equipment it is installed in. The AHJ must use good judgment when providing practical application of this rule so the unprotected service conductors are not extended for unreasonable distances within the building or structure service. Communication and mutual agreement between the AHJ and installing contractor are essential.

Grouping concerns

Another gray area is in Section 270.72(A), which indicates that the two to six service disconnects permitted by Section 230.71 shall be grouped. The NEC never tells the user how far apart they can be installed or if they must be in sight from (another defined term) one another. Being in sight from one another would be ideal, but is not mandatory  in the grouping scenario.

Once again, one must understand the practical application to meet the desired objectives. The grouping requirement allows for occupants or responders to be able to disconnect the power to a building or structure served by not more than six throws of the hand. These occupants or responders should not have to spend time looking for the six means of disconnect. The grouping requirement should result in ease of operation in disconnecting the service.

If gray areas are identified, it is best to engage the AHJ for the best outcome.