What you need to know about the local AHJ’s role in the design process

Ensure a code-compliant electrical design by involving the authority having jurisdiction early.

By John F. Hiester, PE, CRB, Raleigh, North Carolina June 14, 2018

Learning objectives

  • Define the role of the local authority having jurisdiction (AHJ)
  • Explore the AHJ’s responsibilities during the design phase
  • Learn the 2017 edition of the National Electric Code (NEC), Article 225

Whether a project is a renovation, addition, tenant up-fit or new construction, all facility designs are subject to compliance from a local AHJ in some form. For life safety, the AHJ is typically the fire marshal, whereas local building inspectors handle specific disciplines (e.g., mechanical, electrical, structural, fire sprinkler, civil, etc.). All states and counties have different regulations and different individuals who operate as the AHJ. Don’t assume that all AHJs have the same mindset or requirements. 

Involving the authority having jurisdiction

National associations like the American Society of Mechanical Engineers and the National Fire Protection Association create standards and codes for architects, engineers, constructors and regulators, but local AHJs also have certain items that they check when reviewing designs and performing inspections during construction. It is up to the engineer and the client to work together early in the design process to determine which design decisions need to involve the AHJ and how to address them. To further complicate matters, it cannot be assumed that all AHJs are up-to-date on all code cycles and have the correct interpretation of all code references. They may need to be informed in the process. When deliberating issues with the AHJ, it is important to document discussions and outcomes that affect design decisions to ensure that those design decisions are justified and acceptable to the AHJ.

It is also important for the design and construction teams to be aware of which building inspector to engage for the appropriate discipline, to know when and where certain types of permit applications apply and to have the ability to coordinate the timing of permitting with particular design milestones. This helps ensure that the project can be constructed in the anticipated timeline of the project schedule. There are several different types of permits and certifications to consider:

  • Residential or commercial
  • Leadership in Energy and Environmental Design (LEED) or another green/sustainable certification
  • Land use, right of way
  • Demolition, renovation, tenant up-fit, change of use, addition or new construction
  • Temporary or permanent utilities
  • Landscape/site lighting, land clearing, grading and fence, underground
  • Fire and life safety
  • Environmental quality and air pollution (See Figure 1).

One or more of these permits (and others) may apply to a project. Perform the due diligence of project-specific verification for all applicable requirements. Some AHJs have requirements that may be county-specific. For instance, a specific county stipulation may include the requirement for a minimum illumination intensity of 1 foot-candle within a parking lot or parking area and may also require that the illumination intensity at the property line not exceed 0.5 foot-candle. Another example of a county-specific condition is a required minimum or maximum paper size required for permitting (e.g., 11-by-17 inches or 24-by-36 inches). Be sure to avoid the pitfalls of delaying a project on account of ignorance of basic county requirements like these. Delays in permitting and project acceptance can potentially lead to construction delays and even liquidated damages for the client. (See Figure 2.)

Remember that codes are subject to change. They are usually updated to provide clarification to regulations that are known to create confusion by interpreters, inspectors, etc. AHJs may have a particular interpretation ingrained in their way of thinking and are not willing to change their opinion based on their interpretation of the letter of the code. As code cycles are renewed, updated articles can clarify particularly confusing code sections and provide answers to conflicting interpretations that are encountered and regularly debated in the field by inspectors and designers.

For example, consider the NFPA 70: National Electric Code, Article 225. This article addresses requirements for the installation of outside feeders and branch circuits—either overhead or underground—and can apply to specific electrical equipment or a power supply to another building or structure.

A common item often addressed by the AHJ regarding industrial installations is with respect to Part II of NEC Article 225 for buildings or structures supplied by a feeder or branch circuit. Article 225.31 requires a disconnecting means for ungrounded conductors entering a building or structure from a separate building or structure at the point of entry inside or outside of the building or structure. There is an exception to this code requirement:

"For installations under single management, where documented safe switching procedures are established and maintained for disconnection, and where the installation is monitored by qualified individuals, the disconnecting means shall be permitted to be located elsewhere on the premises." 

Steps to take to ensure a successful electrical design

This exception is commonly taken by industrial clients who are able to generate detailed documentation demonstrating that the lockout/tagout (LOTO) procedures in place for the facility allow for the safe switching of energized circuits and feeders. The engineer of record must be cautious when executing the electrical design for a facility planning to take this exception. Taking the following steps early in the design effort will help ensure an adequate electrical design with minimal rework and help eliminate the possibility of litigation afterward:

  • Document discussions held with the AHJ and client to justify the design direction.
  • Ensure that the client is aware of the requirements and conditions set forth and enforced by the AHJ.
  • Ensure that the engineer, client and AHJ are all in agreement.
  • Know your codes and which code cycles are in effect for your jurisdiction. Be prepared to deliberate with your AHJ. Research all aspects of the code applicable to your client’s facility and be prepared to communicate in detail how the facility will meet any exception(s) taken.
  • Ensure that the client is included in as many discussions and design decisions as possible. The AHJ may require documentation that only the client can provide. Your client will be able to explain its standard operating procedures better than you and will be most familiar with how its facility will operate, how staff shifts will be arranged, and what its staff members’ qualifications and responsibilities will be.

Let’s take the following scenario as an example: A prefabricated electrical room will serve a new 24-hour industrial manufacturing production facility but will be a separate stand-alone structure located elsewhere on the premises. In compliance with Part II of NEC Article 225, the owner will need to provide documentation that its facility will have safe switching and disconnecting procedures under single management and under the supervision of qualified personnel. To meet the aforementioned exception for an industrial establishment under single management, the AHJ may require documentation that the facility is staffed with a qualified licensed engineer or electrician and will likely request specific staff logs. In addition, the AHJ will likely require documentation indicating methods of procedures identifying specific LOTO measures for each applicable piece of equipment. It is important that the engineer and client are aware and prepared to provide this documentation long before design completion. The inability to meet the full scale of AHJ requirements may ultimately result in the need for a redesign. Therefore, it is critical that the engineer and the client are in agreement and prepared to meet the entire range of AHJ requirements.

Now, let’s look at another code item that is often enforced by AHJs: NEC Article 225.36. Prior to the 2014 NEC cycle, this article read as follows: "225.36, Suitable for Service Equipment. The disconnecting means specified in 225.31 shall be suitable for use as service equipment." AHJs will reference this article and cite the need for the upstream disconnect(s) of a feeder or branch circuit serving a separate building or structure to be "service entrance-rated." This is often impractical in industrial installations. Let’s take the aforementioned prefabricated stand-alone electrical room as an example. Let’s assume that the design is such that motor control centers (MCCs) will serve production motor loads in the manufacturing facility, with each circuit fed from the MCC essentially leaving one building or structure and entering another building or structure. Trying to rate each disconnect at the MCC as a service entrance is neither practical nor feasible with most MCC manufacturers.

Luckily, the 2017 edition of the NEC has since been revised to help resolve this predicament. The 2017 edition of NEC Article 225.36 now states, "225.36, Type of Disconnecting Means. The disconnecting means specified in 225.31 shall be comprised of a circuit breaker, molded case switch, general-use switch, snap switch, or other approved means. Where applied in accordance with 250.32(B). Exception, the disconnecting means shall be suitable for use as service equipment." In reading this updated excerpt, it is clear that the intention of this code is not to rate each disconnect located inside the MCC as a service entrance to serve a load located in a separate building or structure. Rather, the service entrance rating is specific to feeder-grounded conductors installed in accordance with NEC Article 250.32(B)(1).

As previously stated, it is critical to stay up to date with knowledge of the most current code cycles. Knowing how to apply applicable code sections will help to avoid the need to confront the AHJ and the need for redesign to meet AHJ requirements.

The engineer should help guide the client and its facility to provide a code-compliant design that will ultimately be signed off by the AHJ. The client should begin planning and preparing early on, with written documentation pertaining to its facility’s standard operating procedures, anticipated shifts, and LOTO safety disconnection and energization procedures. With all of the right steps in place, you can rest assured that the facility meets the needs of the client, the requirements of the AHJ and the design intent of the engineer.

John Hiester, an electrical engineer with CRB, has more than 10 years of experience designing and specifying electrical systems. His primary market emphasis includes science + technology, with experience ranging from research and development labs, animal research, pharmaceutical, biotech, food and process manufacturing, health care, mission critical and higher education. Hiester is a key proponent for CRB’s ONESolution™ (design-build) initiative, which focuses on providing in-house turnkey solutions for the design, permitting and construction of coordinated construction documents. This streamlined approach provides unique cost estimating, scheduling and phasing abilities. Hiester is proactive in employing efficient design solutions with an emphasis on modular, flexible and scalable opportunities in an effort to meet a variety of challenges to meet varying design needs. Hiester is active in engaging team-wide collaboration to simplify coordination efforts among the design team, construction staff and client to promote and encourage comradery throughout the process. CRB is a CFE Media content partner.