Switch-Rated Plugs and Connectors Demonstrate Clear Disconnect
Last month, the Occupational Safety and Health Administration (OSHA) announced that it is seeking input on potential updates to its lockout/tagout standard first published in 1989. OSHA is specifically requesting information to reflect new industry best practices and technological advances for hazardous energy control in the robotics industry and related to control circuit type devices.
OSHA defines “lockout/tagout” as the specific practices and procedures used to safeguard employees from the unexpected energization or startup of machinery and equipment, or the release of hazardous energy during service or maintenance activities. It also estimates that following proper LO/TO procedures prevents an estimated 120 fatalities and 50,000 injuries each year.
To currently demonstrate proper compliance with LO/TO procedures, it may require donning cumbersome personal protective equipment and opening the switch to manually probe wires using a volt meter to confirm zero power. The replacement time for a single electric motor could take up to three hours and involve multiple tradespeople, due to code and safety requirements. While time-consuming, taking shortcuts in this process can lead to serious injuries.
One way to address these time and labor challenges is to utilize switch-rated plugs and connectors listed under UL 2682. Unlike standard connectors, devices listed under UL 2682 can operate as switches and be used to disconnect loads, even when energized. Spring-loaded silver-alloy contacts provide switching capabilities similar to a circuit breaker or contactor, with the connector remaining engaged during operation to protect users from arc flash and contact with live electrical components. A two-step connector operation places the plug in a rest position after disconnection, requiring a rotating motion to remove the plug while simultaneously closing the receptacle shutter.
Sections 430.102 – 430.109 of the National Electric Code (NEC) require approved disconnecting means to be located in a readily accessible location within sight of the motor location and driven machinery. This can often be a challenge as disconnect switches can be difficult to locate near machinery due to space or mounting constraints and/or require electricians to perform this task.
With a switch-rated connector system, the plug being separated from the receptacle provides visual proof that power has been removed and displays fast and positive compliance with NEC requirements for de-energizing industrial equipment.