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The National Electrical Code (NEC), or NFPA 70, is a regionally adoptable standard for the safe installation of electrical wiring and equipment in the United States. It is part of the National Fire Code series published by the National Fire Protection Association (NFPA), a private trade association . [ 1 ]
The motor size constant and motor velocity constant (, alternatively called the back EMF constant) are values used to describe characteristics of electrical motors. Motor constant [ edit ]
This produced the Antenna Modeling Program, or AMP, which was extensively modified to support disk-based files, simplify the input and output to make it easier to use, and extensively documented. A follow-up, AMP2, added calculations for extended surfaces like reflectors. [2] NEC is an advanced version of AMP2, with more options and features.
NEMA (National Electrical Manufacturers Association) contactors and motor starters are rated by sizes. These sizes are grouped by rated current and power. [1] [2]
The introduction of the NEC clearly states that it is not intended to be a design manual, and therefore creating a colour code for ungrounded or "hot" conductors falls outside the scope and purpose of the NEC. However, it is a common misconception that "hot" conductor colour-coding is required by the Code.
Usually utilization category is mentioned in most of the switch gear, with the above contactor stating to be used under AC1 - resistive load & AC3 for motor usage. In electrical engineering utilization categories are defined by IEC standards [1] and indicate the type of electrical load and duty cycle of the loads to ease selection of contactors ...
In the power systems analysis field of electrical engineering, a per-unit system is the expression of system quantities as fractions of a defined base unit quantity. . Calculations are simplified because quantities expressed as per-unit do not change when they are referred from one side of a transformer to t
While the various OSHA, ASTM, IEEE and NEC standard provide guidelines for performance, NFPA 70E addresses practices and is widely considered as the de facto standard for Electrical Safety in the Workplace. Practices include: Staging a "safe work zone" with boundaries, barricades, signs and attendants.