follow The NEC is also available as a restricted, digitized coding model that can be read online but not saved, copied and pasted, or printed, free of charge on certain computing platforms that support the restricted viewer software. In the United States , statutory law cannot be copyrighted and is freely accessible and copyable by anyone. For that privilege, the coding model must still be purchased as either printed media or electronic format e.
Once the coding model has been accepted as law, it loses copyright protection and may be freely obtained at no cost. The introduction sets forth the purpose, scope, enforcement and rules or information that are general in nature.
The first four chapters cover definitions and rules for installations voltages, connections, markings, etc. The next three chapters deal with special occupancies high risk to multiple persons , special equipment signs, machinery, etc. Annexes A-J relate to referenced standards, calculations, examples, additional tables for proper implementation of various code articles for example, how many wires fit in a conduit and a model adoption ordinance. The introduction and the first 8 chapters contain numbered articles, parts, sections or lists or tables italicized exceptions, and Informational notes — explanations that are not part of the rules.
Articles are coded with numerals and letters, as. For example, Each code article is numbered based on the chapter it is in.
Those wiring methods acceptable by the NEC are found in chapter 3, thus all approved wiring method code articles are in the s. Efforts have been underway for some time to make the code easier to use. Some of those efforts include using the same extension in those code articles for the support of wiring methods. The NFPA also publishes a 1,page NEC Handbook for each new NEC edition that contains the entire code, plus additional illustrations and explanations, and helpful cross-references within the code and to earlier versions of the code.
The explanations are only for reference and are not enforceable. Many NEC requirements refer to "listed" or "labeled" devices and appliances, and this means that the item has been designed, manufactured, tested or inspected, and marked in accordance with requirements of the listing agency. Upon payment of an investigation fee to determine suitability, an investigation is started. To be labeled as fit for a particular purpose for example "wet locations", "domestic range" a device must be tested for that specific use by the listing agency and then the appropriate label applied to the device.
A fee is paid to the listing agency for each item so labeled, that is, for each label. Most NRTLs will also require that the manufacturer's facilities and processes be inspected as evidence that a product will be manufactured reliably and with the same qualities as the sample or samples submitted for evaluation. An NRTL may also conduct periodic sample testing of off-the-shelf products to confirm that safety design criteria are being upheld during production.
Because of the reputation of these listing agencies, the "authority having jurisdiction" or "AHJ" — as they are commonly known usually will quickly accept any device, appliance, or piece of equipment having such a label, provided that an end user or installer uses the product in accordance with manufacturer's instructions and the limitations of the listing standard.
However, an AHJ, under the National Electrical Code provisions, has the authority to deny approval for even listed and labeled products.
Likewise, an AHJ may make a written approval of an installation or product that does not meet either NEC or listing requirements, although this is normally done only after an appropriate review of the specific conditions of a particular case or location. The electric code makes a distinction between "high" voltages above volts, and "low" voltages below that. For circuits defined as low voltage, in some jurisdictions, there is no requirement for licensing, training, or certification of installers, and no inspection of completed work is required, for either residential or commercial work.
Low voltage cabling run in the walls and ceilings of commercial buildings is also typically excluded from the requirements to be installed in protective conduit. Although low voltage cabling does not require inspection or training to install in some jurisdictions, it is still important for installers to be aware of specific safety rules such as how to correctly penetrate building fire barriers. Article addresses "branch circuits" as opposed to service or feeder circuits and receptacles and fixtures on branch circuits. Ten important items in Article have been summarized in a codebook.
Feeder and branch circuit wiring systems are designed primarily for copper conductors.
Aluminum wiring is listed by Underwriters Laboratories for interior wiring applications and became increasingly used around due to its lower cost. Prior to , however, the aluminum wire used was manufactured to conform to the series aluminum alloy, but this alloy was eventually deemed unsuitable for branch circuits due to galvanic corrosion where the copper and aluminum touched, resulting in poor contact and resistance to current flow, connector overheating problems, and potential fire risk.
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As the number one pocket reference guide in the industry, this is a must-have for professional building and technical trade contractors, service technicians, maintenance personnel, plant managers, engineers, designers, and architects alike. Compliance with the National Electrical Code is a major concern for today? Residential Wiring and Smart Home Technology - Residential Wiring and Smart Home Technology focuses on the principles, installation, and operation of wired and wireless residential electrical and electronic systems. It's designed to help contractors and installers focus quickly on the task at hand, so you can improve your efficiency and accuracy! If it does, at least you would know when to proceed with caution if you look up a table value, or reference an article for the exam, and the information you need is shaded to indicate that it has changed in the edition. When you are looking to pass an exam and you want to study at your own pace, then you can't beat this Exam Preparation Library.
Online Exams. Practice Exams. Great Gift Ideas! Rather, it also spans to include electronic equipment as well as communication systems and equipment. Users can reference NFPA 70B for guidance on systems and equipment installed in the following locations:.
NFPA 70B spans 35 chapters and covers maintenance intervals and procedures for electrical equipment and systems. In addition, 16 annexes are also included. These provide helpful explanations and recommendations. Finding parts that comply with industry standards, such as the National Electric Code or NFPA 70, can take the guesswork out of this step. Take a look around and contact us for support. Disclaimer: The content provided is intended solely for general information purposes and is provided with the understanding that the authors and publishers are not herein engaged in rendering engineering or other professional advice or services.
The practice of engineering is driven by site-specific circumstances unique to each project. Consequently, any use of this information should be done only in consultation with a qualified and licensed professional who can take into account all relevant factors and desired outcomes. The information was posted with reasonable care and attention. However, it is possible that some information is incomplete, incorrect, or inapplicable to particular circumstances or conditions.
We do not accept liability for direct or indirect losses resulting from using, relying or acting upon information in this blog post. Ready to learn more? What is NFPA 70? The new standard also outlines the key data that users should include on each label, including: Nominal system voltage Clearing time of service overcurrent protective devices determined by the available fault current at the service equipment The date that the user applied the label Revisions Made to Stay Relevant In addition to basic updates to installation and maintenance procedures, NFPA 70 updates also serve to keep it relevant and ensure that installers stay current in their practices.
Circuits and circuit protection Wiring methods and materials e.
These cover: Special occupancies e. Some of the most useful annexes include: Details on referenced standards Calculations Real-life examples and applications Additional tables to help users implement the myriad code articles e. A a For example, if you find Article Users can reference NFPA 70B for guidance on systems and equipment installed in the following locations: Industrial plants Institutional buildings Commercial buildings Large, multi-family residential complexes NFPA 70B spans 35 chapters and covers maintenance intervals and procedures for electrical equipment and systems.