I first became involved in the NEC as a panel member in 1981. I served two cycles as a panel member before I joined the NFPA staff. I became the secretary and staff liaison to the NEC in July 1989 and retired in August 2019.
This is the first cycle in 40 years where I am neither a committee member nor staff. However, I submit public input and public comments, and I now have experienced and appreciated the NEC from three different perspectives. With that in mind, I will present a series of articles about the changes ahead for the 2023 National Electrical Code .
NEC Style Manual
The new NEC Style Manual makes the Code as consistent, straightforward and usable as possible. We say “usable” rather than “user-friendly.” Usability is the goal, since the Code establishes technical requirements and doesn’t provide recommendations or guidance. The NEC says that “this Code is not intended as a design specification or an instruction manual for untrained persons.”
All 18 panels undertook major rewrites during this cycle. It is unglamorous work to make the language of the Code more readable. Once, to help someone with a Code question, I opened the Code book to be confronted by a four-paragraph rule. Only the first paragraph was numbered. That is a complicated rule that contains embedded rules. Often, such a rule is followed by informational notes. If the rule needs to be explained further, it is time to rewrite it.
Text shading is used to indicate changes. The 2023 Code will likely have plenty of shaded text. While many of those changes will not move the needle from a technical standpoint, they will significantly improve our ability to understand the requirements.
The Code applies to AC and DC systems. DC use is growing, especially in renewable energy requirements. Many AC requirements have been written around requirements for systems of 1,000V and less or greater than 1,000V (medium-voltage). A new limit was established for DC systems at 1,500V DC. This is reflected in the text and in some of the article titles.
New, deleted and relocated articles and revised titles
Starting at the highest level—articles—there are a number of changes.
- 110—General Requirements for Electrical Installations (Revised title). The entire
Codeis dedicated to requirements for electrical installations. Adding the word “general” better describes Article 110’s role.
- 231—Electric Power Sources Interconnected with an Electric Utility (New). This new article is intended to provide closer coordination with renewable energy systems that operate in parallel with the utility and are connected to service equipment. This effort was begun by CMP-10, which has responsibility for Article 230.
- 235—Branch Circuits, Feeders, Outside Feeders and Branch Circuits and Services Over 1,000V (New). The medium-voltage requirements will be removed from articles 210, 215, 225 and 230 and consolidated into this new one.
- 245—Overcurrent and Overvoltage Protection for Systems Rated Over 1,000 Volts AC, 1,500 Volts DC (New). This is another effort to separate medium-voltage requirements from those circuits rated 1,000V and less. Part IX was removed from 240 to become the basis for Article 245.
- 305—Requirements for Wiring Methods and Materials for Systems Rated Over 1,000 Volts AC, 1,500 Volts DC, Nominal (New). During the first-draft stage, this included Part II of Article 300 and articles 314, Part IV, 368, Part IV and Article 399. In the second-draft stage, the panel decided to limit Article 305 to what had been Part II of Article 300 and to retain the other material in articles 314, 368 and 399.
- 315—Medium-Voltage Conductors, Cable, Cable Joints, and Cable Terminations (Revised title and relocated). This article was new in the 2020
Codeas Article 311. Cable joints and cable terminations were added to the title and content.
- 335—Instrument Tray Cable (Relocated). This was Article 727 and has been assigned to CMP 3. It is likely to be reassigned to CMP 6 since they have responsibility for cable wiring methods in Chapter 3.
- 337—Industrial Mobile Cable, Type IM (Revised title). This article was new in the 2020
Codeas “Type P Cable.” The title was revised in the first-draft stage to “Drilling Rig Cable, Type P” to reflect its original applications. The new title and acronym were chosen in the second-draft stage, so as to not reflect a marine application.
- 369—Insulated Bus Pipe (IBP)/Tubular Covered Conductors (TCC) (New). This article covers a new product that has two names. IBP (or TCC) is defined as “A cylindrical solid or hollow conductor with a solid insulation system, having conductive grading layers and a grounding layer embedded in the insulation, and provided with an overall covering of insulating or metallic material.” An insulated bus pipe system includes the bus pipe, along with fittings, mounting structures and accessories. Like many wiring methods, IBP is required to be listed.
- 371—Flexible Bus Systems (New). This is another new wiring method article. Flexible bus is defined as “A flexible rectangular conductor with an overall insulation.” Like IBP, a flexible bus system (FBS) includes the associated fittings used to secure, support and terminate the flexible bus. FBSs are required to be listed, and they are systems-engineered for the specific installation. The FBS must be designed and specified for the installation by a qualified engineer within the limits of the listing and the manufacturer’s installation instructions. The product listing standard currently only recognizes FBS for systems rated 1,000V and less.
- 395—Outdoor Overhead Conductors over 1,000 Volts (Relocated). This used to be Article 399. This cycle, a new article numbering convention was implemented to end medium-voltage articles with the number 5, e.g., Articles 235, 245 and 305.
- 480—Stationary Standby Batteries (Revised title). When Article 706 was introduced in the 2020
Code, the requirements were not integrated into Article 480. Article 480 can trace its roots back to the NEC’s first edition. It was felt that storage batteries were different than the new generation of energy storage systems and that it was necessary to provide separate requirements for these legacy systems. Article 480’s title has been changed to “Stationary Standby Batteries” to further differentiate them. In addition, the article is now limited to batteries with lead-acid or nickel-cadmium cells.
- 495—Equipment Over 1,000 Volts AC, 1,500 Volts DC, Nominal (Revised and Relocated). This article was previously located as Article 490. It was moved to Article 495, in accordance with the numbering convention.
- 510—Hazardous (Classified) Locations-Specific (Deleted). This article was unnecessary and had outlived its usefulness.
- 512—Cannabis Oil Equipment and Cannabis Oil Systems Using Flammable Materials (New). This new article addresses the hazards of cannabis processing using flammable materials. The substantiation noted that processes have involved butane, pentane, hexane and ethanol. The substantiation for the public input noted several incidents involving fires and explosions.
- 720—Circuits and Equipment Operating at Less Than 50 Volts (Deleted). Although this article covered AC and DC systems, it was originally written to address stand-alone electrical systems for farms that operated at 32V DC. These systems have not been used in many years. DC systems are now addressed in other
- 722—Cables for Power Limited Circuits (New). This new article addresses cable requirements that had been covered in articles 725, 760 and 770. The intent is to avoid replicating requirements.
- 724—Class 1 Circuits (New). The requirements for Class 1 circuits were relocated here. The definition of Class 1 has also been revised to apply only to power-limited circuits that operate at a maximum of 30V and 1,000 volt-amperes. Nonpower-limited remote control and signaling circuits are covered in chapters 1–4.