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Motor Got Disconnected

By Michael Johnston | Aug 15, 2015
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For many years, The National Electrical Code (NEC) has provided rules for equipment disconnects. NEC requirements are very specific for motors and motor-driven machinery, but they differ from lockout/tagout rules in NFPA 70E, Standard for Electrical Safety in the Workplace. The reason is simple. The NEC is an installation code, and its requirements apply to installed equipment. The NFPA 70 requirements deal with workplace safety-related rules and practices. Compliance with one code can facilitate compliance with another.


Disconnect for controllers


Based on the general requirement in NEC 430.102(A), each motor controller requires a disconnecting means, such as a magnetic motor starter, and it must be located “within sight from” the controller. NEC Article 100 defines the term “within sight.” (There are three exceptions to this requirement, but I focus on the general rule here.) Anyone working on the controller, such as performing service work or maintenance, has the security of a so located disconnecting means. Many standalone combination magnetic motor starters include a disconnecting means and controller in the same enclosure. The same holds true for many combination controllers installed in motor control centers. So compliance with 430.102(A) is often (but not always) integral to the manufactured products. If individual disconnects and controllers are installed, there must be a careful focus on their location to ensure compliance with the general rules.


In clear sight


The disconnect rule for motors, including the requirements for disconnecting means locations, are provided in 430.102(B). This general rule is that a disconnecting means must be provided in sight from a motor and the driven machinery. Since Article 100 defines the phrase “in sight from,” it is clear that the disconnect, motor and driven machine must be visible from each other and at a distance not exceeding 50 feet. Note that the rule does not mention accessibility or a requirement that the disconnecting means be readily accessible from the motor. Although this would be the best installation, it would exceed the NEC’s minimum requirements. Note that the controller disconnecting means required in 430.102(A) could also satisfy the disconnecting means requirement for the motor and driven machinery if it is located within sight from both the controller and the motor location.


Out of sight


As with many general rules in the NEC, there are exceptions. In achieving compliance with the exception, all conditions of the exception must be satisfied. It is important to read the entire exception and any other sections referred to from the exception. That said, the motor and controller disconnecting means addressed in 430.102(A) and (B) are not required to be located in sight from the motor and driven machinery location if it is lockable and meets all of the conditions specific in Section 110.25. A review of 110.25 reveals that the out-of-sight disconnecting means must be capable of being locked in the open position. The provisions for locking shall remain in place with or without the lock installed. Most manufactured disconnects and magnetic motor starters have this capability as an integral part of the equipment.


The key here is that the provision to be able to add the lock must remain with the switch or circuit breaker because it is part of the installation covered by the NEC rules. The question is often raised about portable locking means that can be carried to a switch or circuit breaker and then temporarily fastened to it in order to install the lock and tag. While this technique may satisfy the lockout/tagout requirements in NFPA 70E, these portable types of disconnect locking means are not compliant with the NEC. To clarify, the permanent provisions for lockable disconnecting means required by 110.25 satisfy both the NEC and NFPA 70E. Any portable disconnect locking devices only meet the requirements in Article 120 of NFPA 70E.


Through the glass


Another common question is about the “within sight from” language in the NEC and whether this could be accomplished through a window. The answer is yes, although it is probably not the best solution for such a safety requirement. Remember that the NEC only requires the motor and driven machinery to be visible from the disconnecting means, not readily accessible from each other. This could be accomplished through glass. It is highly advisable and a good practice to always attach the lock and tag when establishing an electrically safe working condition.


Remember the Code is the minimum, meaning one must do at least that much to comply. This is a good example of how the NEC requirements complement the workplace safety rules in NFPA 70E to assist electricians in meeting both requirements and staying safe. Also, it is also always a good idea to consult with the authority having jurisdiction to ensure how they will interpret and apply the applicable Code requirements for motors and motor controller disconnecting means locations.

About The Author

A man, Mike Johnston, in front of a gray background.

Michael Johnston

NECA Executive Director of Codes and Standards

JOHNSTON is NECA’s executive director of codes and standards. He is a member of the NEC Correlating Committee, NFPA Standards Council, IBEW, UL Electrical Council and NFPA’s Electrical Section. Reach him at [email protected].

 

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