Requirements that help remove hazards
The National Electrical Code includes more than 60 requirements to install a disconnecting means within sight from equipment. These requirements are safety-driven and ensure that workers and other personnel can open the circuit supplying equipment. This general requirement for providing a means to disconnect to power allows workers to remove hazards—such as electric shock and arc-flash events—if work was done while circuits were energized. Always shut the power off before working on equipment.
The NEC rules on to disconnecting means locations are designed to facilitate an electrically safe work condition. The NEC rules work hand-in-hand with the requirements for achieving electrical safety as set forth in NFPA 70E, Standard for Electrical Safety in the Workplace.
Required disconnecting means rules have evolved over the years to address multiple concerns and improved safety as a result. Before such requirements emerged in the Code, many became victims of electric shock and electrocution. These hard lessons are clear examples of how the NEC has helped facilitate improvements in safer working environments. It is important to point out that as the equipment disconnecting means requirements grew throughout the NEC, so did exceptions to about every one of these general requirements. An important thing to remember about applying any Code rule, or any exception to an installation or system, is to fully understand the rule and all provisions of any exceptions that can be allowed to attain minimum compliance.
In the case of exceptions to the required equipment disconnects addressed in the NEC, the Code provides a consistent set of requirements located in Article 110 where the general requirements for electrical installations are found. The section referred to here is 110.25. We use the example in Section 430.102(A) and Exception No. 1 that reads as follows:
“430.102 Location. (A) Controller. An individual disconnecting means shall be provided for each controller and shall disconnect the controller. The disconnecting means shall be located in sight from the controller location. Exception No. 1: For motor circuits over 1,000 volts, nominal, a controller disconnecting means lockable in accordance with 110.25 shall be permitted to be out of sight of the controller, provided that the controller is marked with a warning label giving the location of the disconnecting means.”
Note the general rule contains the “in sight from” requirement for the disconnecting means and the controller. One must be located “in sight from” another; Article 100 clarifies the parameters of this term. The exception provides relief from having to meet the “in sight from” requirement, but a remote (out of sight) disconnecting means for the controller must be provided, be lockable and meet all the conditions provided in Section 110.25. A review of this section reveals that where a disconnecting means is required to be lockable in the open position throughout the Code, the disconnecting means must first be capable of being locked in the open (off) position.
The second stipulation here is that the provision for adding the lock must be installed and remain with the switch or circuit breaker, whether a lock is installed or not. This means it must be part of the permanent electrical installation. A portable provision for adding a lock cannot be carried to the switch or circuit breaker and used as a locking means to meet the NEC rules. It must be part of the installation. Many types of electrical equipment provide such features with a switch or circuit breaker as an integral part. Accessory features can be obtained from manufacturers to be field-installed on equipment and meet the requirement of remaining with the switch or circuit breaker, whether the lock is installed or not. It is there for personnel to apply their lock and create an electrically safe work condition.
There are many references to Section 110.25 from exceptions to the “in sight from” disconnecting means rules throughout the NEC. Having one set of rules for the lockable “out of sight” disconnecting means enhances consistency in allocating requirements while helping facilitate electrical safety in the workplace relative to meeting lockout/tagout requirements in OSHA regulations and as provided in Article 120 of NFPA 70.
The NEC’s safety-related installation rules in the are only effective if they are diligently applied by personnel that strive to remove the electrical hazards by disconnecting the power. Use the locking means. It is there for your safety and the safety of others.