Protecting people and property from electrical hazards is a complex issue that, unfortunately, cannot be handled by a single code or standard. Due to the nature of these hazards, many different documents are needed in order to achieve the desired end result. These documents work together as part of a bigger picture to help save lives and prevent loss.
With respect to the National Electrical Code® (NEC®) and its interrelated documents, the following illustrates the three tiered approach to how these documents work together within the bigger picture.
Performance documents
These documents contain requirements for how a system is intended to perform. In other words, there is an objective to these documents that drives the design of the applicable system. They give the code or standard user an idea of what the system needs to do in order to accomplish the purpose of the document. Examples include the following:
Installation documents
These documents contain the requirements for how to install the system in order to meet the objectives of the other performance level documents. They work together to help the code user know what to do and how to do it. Examples include:
Supporting documents
These documents feed information into the installation documents. They provide information about specific conditions that have special installation requirements. Examples of supporting documents include the following:
- NFPA 30, Flammable and Combustible Liquids Code
- NFPA 30A, Code for Motor Fuel Dispensing Facilities and Repair Garages
- NFPA 33, Standard for Spray Application Using Flammable or Combustible Materials
- NFPA 34, Standard for Dipping, Coating, and Printing Processes Using Flammable or Combustible Liquids
- NFPA 75, Standard for the Fire Protection of Information Technology Equipment
- NFPA 497, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas
- NFPA 499, Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas
When we take a step back to look at the entire picture, the relationships between the different documents begin to take shape. It becomes clear how these documents form a partnership in order to achieve NFPA’s mission to help save lives and prevent loss. The performance and installation documents work together to build a system that is safe and achieves the desired objective, while the supporting documents provide information that is imperative to the proper system installation with the conditions present.
A fire alarm system is a great example of how these relationships work. Generally, a document other than the NEC — perhaps NFPA 101®, Life Safety Code®, or NFPA 5000®, Building Construction and Safety Code®, or the building code that is adopted and enforced within the jurisdiction — is the document that requires a fire alarm system to be installed. Once it has been determined that a fire alarm system is needed, NFPA 72, National Fire Alarm and Signaling Code, is used, which contains the requirements for how the system will need to be designed in order to meet the performance requirement. This includes detector placement requirements, notification requirements, inspection and maintenance requirements, and other requirements that will ensure that the system performs as needed. Ideally, this takes place during the design stage. The next stage is the physical installation of the fire alarm system. For these requirements, the NEC is used. The NEC contains requirements for the installation of the wiring and equipment of the fire alarm system. Requirements for items such as junction boxes, raceways, and cable types are found in the NEC. The NEC also contains the requirements for how to install these items, such as securing and supporting, fastening, and raceway fill. Together these two documents — the NEC and NFPA 72 — provide the requirements for installing a fire alarm system that meets the requirements of the building or life safety code.
Sometimes an installation occurs in an environment that requires modification to the general installation materials and methods. This is where the supporting documents come in to play. The environment where this fire alarm system is being installed might contain conditions that warrant special modifications to the system. For instance, if the system is being installed within a facility that handles flammable gases and liquids, the level of hazard that is present needs to be determined in order to make the appropriate modifications. This type of information can be found in documents such as NFPA 497. Information found in this document will help determine which areas of the facility are classified and which are not. The installation code, in this case the NEC, is then used to modify the installation in the classified or hazardous areas of the facility. This provides a system that is installed safely in all conditions present and that will perform how it is required to.
Also within the NEC family of documents are NFPA 70B, Recommended Practice for Electrical Equipment Maintenance, and NFPA 70E®, Standard for Electrical Safety in the Workplace®. Together, these three documents — the NEC, NFPA 70B, and NFPA 70E — form a sort of three-legged stool for safe electrical installations. When the electrical system is installed properly per the NEC and maintained following the guidelines of NFPA 70B, all while using the work practices described in NFPA 70E, the system remains at the same level of safety as when it was installed. This ensures that the performance requirements to which the system was designed continue to be achieved. If a single leg of this stool is missing, the structure comes crumbling down. Even the highest quality electrical installation will fail if it is not properly serviced and maintained.
There are also some documents that, due to the nature of their subject matter, are essentially stand-alone documents. While NFPA 77, Recommended Practice on Static Electricity, and NFPA 780, Standard for the Installation of Lightning Protection Systems, both deal with mitigating hazards that arise from electricity, static, and lightning, they are not part of the safe electrical system installation that is achieved by the NEC and its related documents. Because these documents are not part of the electrical system, they contain requirements that come from all three levels of protection: performance, installation, and supporting. They both are worth noting because they still fit within NFPA’s mission to help save lives and reduce loss.