What does NEC Article 430 Part IX require?
What does NEC Article 430 Part IX require?
Part IX. You need a disconnect for each motor controller. You must locate it within sight of the controller (see Figure 430-20). “Within sight” means visible and not more than 50 ft from each other [Article 100].
In which part of Article 430 would you expect to find requirements for sizing branch circuit conductors?
While the MCC itself must be installed in accordance with Article 430, Part VIII, the motor branch circuit conductors and motor circuit components must be sized and installed in accordance with provisions located in other parts of Article 430. Requirements for motor branch circuit conductors are in Part II.
What article in the NEC covers motor overloads?
This article is based upon the 2017 edition of NEC. Part III of Article 430 covers overload protection for the motor and its circuit. It is important to protect motors, motor control equipment and motor branch circuit conductors from motor overloads and excessive heat.
What section of Article 430 is used to size overload protection for a single motor rated 1hp or more?
Requirements pertaining to motor and branch-circuit overload protection are in Part III of Article 430. As stated in 430.31, Part III specifies overload devices intended to protect motors, motor-control apparatus, and motor branch-circuit conductors against excessive heating due to motor overloads and failure to start.
What is the purpose of Article 430 in the NEC?
Article 430 in the National Electrical Code (NEC) is titled “Motors, Motor Circuits and Controllers.” As the scope of the article states, it covers motors, motor branch-circuit and feeder conductors, motor branch-circuit and feeder protection, motor overload protection, motor control circuits, motor controllers, and …
Do all motors need overload protection?
EVERY motor needs overload protection of some type. Some small motors are impedance protected by design. Some motors can be overload protected by breakers or fuses. Some motor have internal temp probes that shut down the motor starter.
Are motors considered continuous load?
A continuous duty motor is treated as a continuous load, a load where the maximum current is expected to continue for three hours or more.
How is motor overcurrent protection calculated?
The overloads are determined using 125% of the FLA, 7A x 1.25 = 8.75A. The maximum allowable size for the overloads is 9.8A. The overloads can be sized at 140% of the FLA if the overloads trip at rated load or will not allow the motor to start, 7A x 1.4 = 9.8A.
What is the most common method used for motor control?
By far the most commonly-used AC motor control method is the use adjustable-speed drives. In most commercial and industrial environments these have supplanted virtually every other motor speed control method. An adjustable-speed drive works on the principle of varying the frequency to vary the speed of the motor.
How long is continuous duty?
The term continuous duty also is defined in Article 100 as operation at a substantially constant load for an indefinitely long time (see Figure 1).
What is Article 430 in the National Electrical Code?
Article 430 in the National Electrical Code (NEC) is titled “Motors, Motor Circuits and Controllers.”. As the scope of the article states, it covers motors, motor branch-circuit and feeder conductors, motor branch-circuit and feeder protection, motor overload protection, motor control circuits, motor controllers, and motor control centers.
What is the scope of Article 430.1?
Article 430.1 provides the scope of this Article. As with previous revisions of the NEC, this Article begins with a “road map” of what Parts affect which aspect of the motor system. Consistently, people have complained that Article 430 is mind-boggling and complex. In reality, the application of motors is complex.
What does Part II of Article 430.21 mean?
As stated in 430.21, Part II specifies ampacities of conductors that are capable of carrying the motor current without overheating under the conditions specified. Another component in the bottom half of Figure 430.1 is the rectangle directly above the drawing of the motor; this rectangle represents motor overload protection.
How to size motor circuit conductors Article 430?
430 Part II explains how to size the motor circuit conductors, which is an area rife with confusion and error. Follow Part II methodically, starting with 430.21 and ending at 430.29. Pay special attention to Table 430.22 (Duty cycle service).