From American Electricians' Handbook, Fourteenth Edition


370. National Electrical Code rules definitely specify certain requirements with respect to the size and location of the component parts of motor branch circuits. The following tables and rules are in accordance with the 2002 edition of the Code. Certain cities have adopted motor wiring tables and rules which may be more exacting than those required by the Code. In such communities these local requirements should be followed in preference to the tables presented herein.

Section 370 through 395 are the rules for conventional motors and motor circuits. Sections 396 through 404 are the rules for air-conditioning and refrigerating equipment which includes a hermetic refrigerant motor-compressor. See Sec. 396.

In the following sections the terminology of the National Electrical Code with respect to within sight is adhered to. A distance of more than 15 m (50 ft) is considered equivalent to being out of sight, even though there may be no obstructions between the two points. several motors but no other equipment except that directly associated with the motors, and (3) a branch circuit supplying one or more motors, lamps, receptacles, and/or electric heaters, etc. (combination load).

Full-Load Motor Currents. According to the National Electrical Code, whenever the current rating of a motor is used to determine the ampacity (current-carrying capacity) of conductors or the ampere ratings of switches, branch-circuit overcurrent devices, etc., the values given in Tables 7 to 10 of Div. 12, including footnotes, should be used in...

Products & Services
Stepper Motors (rotary)
Stepper motors use a magnetic field to move a rotor in small angular steps or fractions of steps. They provide precise positioning and ease of use, especially in low acceleration or static load applications.
Stepper Motor Drives
Stepper motor drives power unipolar and bipolar stepper motors in full step, half step, and microstep motion control applications.
Motor Starters and Contactors
Motor starters and contactors are motor-starting devices. They combine a contactor with overload protection and are designed for starting AC or DC motors.
Motor Bases

Motor bases are mounts for electric motors. They often include several bolt patterns for various sized motors and a belt tensioning mechanism. Most are designed to fit NEMA motor sizes.

Electrical Contracting Services
Electrical contracting services install and maintain electrical distribution equipment; interior, exterior and municipal lighting; security systems and closed circuit television systems (CCTV); and information technology or IT systems.

Topics of Interest

CONTROL CIRCUITS 393. Electric control circuits constitute a broad subject, and the reader is urged to refer to special books devoted to this important phase of motor circuitry. Two such books are...

The shaft of a stepper motor moves between discrete rotary positions typically separated by a few degrees. Because of this precise position controllability, stepper motors are excellent for...

National Electrical Contractors Association, Inc. Washington, D.C. GLOSSARY Frequently used terms are defined here. More complete definitions are available in the latest edition of the National...

Table No. Table Title 1 Standard Sizes of Lamps for General Illumination, in Watts 12.3 2 to 6 Demand Factors and Data for Determining Minimum Loads 12.4 7 to 10 Full-Load Currents of Motors 12.10...

Overview This chapter focuses on the wiring and devices used in residential and office branch circuits. It starts by reviewing the National Electrical Code (NEC 2002) branch circuit requirements and...

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