This edition of NFPA 70, National Electrical Code, was prepared by the National This edition includes the following usability features as aids to the user. peypredkoefritlec.cf (file size: 7 MB, MIME type: application/pdf). National Electric Code Edition. NATIONAL ELECTRICAL CODE. ❑ Placement of Electrical Receptacles. [ (A-H)]. •habitable rooms: wall space 2' or wider; no point >6' from.
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The National Electrical Code CD - advancing electrical safety requirements with the edition in an effort to maximize public safety, emergency preparation. Get free online access to NFPA's National Electrical Code® and all NFPA standards. Adopted in all 50 states, the NEC is the benchmark for safe electrical design, installation, and inspection to protect people and property from electrical hazards.
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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 Code has user-friendly features to aid the reader in seeing changes.
Revisions or additions to the articles from the version are highlighted in gray shading. 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.
In more recent terms, the upper cutoff for what is considered low is approximately 50 Volts, with most computer network equipment operating at 48 Volts DC or lower, and not requiring special training to connect or use.
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 electric code safety rules such as how to correctly penetrate building fire barriers and use firestop putty intumescents to prevent a low voltage cable from reducing building fire protection and increasing the risk of injury or death for building occupants.
Access to such safety information is typically restricted and limited access by the electrical industry itself so as to only permit licensed professionals to learn the NEC rules and educate themselves. 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.
Today, a new aluminum wire AA has been approved for branch circuits that does not cause corrosion where it contacts copper, but it is not readily available and is not manufactured below size 8 AWG. Hence, copper wire is used almost exclusively in branch circuitry.
A ground fault circuit interrupter GFCI is required for all receptacles in wet locations defined in the Code.
The NEC also has rules about how many circuits and receptacles should be placed in a given residential dwelling, and how far apart they can be in a given type of room, based upon the typical cord length of small appliances.
As of the NEC required that new Volt household receptacle outlets, for general purpose use, be both grounded and polarized. NEMA connectors implement these requirements. The Code required that new Volt receptacles be grounded also, which necessitates a fourth slot in their faces.
Changes in standards often create problems for new work in old buildings. Unlike circuit breakers and fuses, which only open the circuit when the current exceeds a fixed value for a fixed time, a GFCI device will interrupt electrical service when more than 4 to 6 milliamperes of current in either conductor leaks to ground. A GFCI detects an imbalance between the current in the "hot" side and the current in the "neutral" side.
One GFCI receptacle can serve as protection for several downstream conventional receptacles. GFCI devices come in many configurations including circuit-breakers, portable devices and receptacles. Another safety device introduced with the code is the arc-fault circuit interrupter AFCI. This device detects arcs from hot to neutral that can develop when insulation between wires becomes frayed or damaged. While arcs from hot to neutral would not trip a GFCI device since current is still balanced, circuitry in an AFCI device detects those arcs and will shut down a circuit.
AFCI devices generally replace the circuit breaker in the circuit. As of the National Electrical Code, AFCI protection is required in new construction on all and amp, volt circuits to bedrooms. In home construction, wiring is commonly allowed directly in walls without additional protection. However, in commercial and industrial buildings, wiring must be protected from damage, so it is more commonly installed inside metal or plastic conduit or ductwork, or passageways cast in concrete.
While some types of cable are protected by flexible spiraled metal armor, it is more common to install conduit and empty ductwork and pull the wire in later. The NEC spends considerable time documenting safe methods of installing cable in conduit, the primary concerns being the abrading of insulation, damage to the wire or insulation caused by sharp bends, kinking, and damage due to excess pulling strain.
A wire pulled with excessive force may break inside the conduit, requiring costly removal and replacement. However, a wire pulled with enough force to stretch the wire, but not break it, creates a hazard of future failure or fire. The stretched wire section will have a thinner cross section and higher resistance than other parts of the cable, and may have damaged insulation.