Before performing electrical work, OSHA and the NFPA 70E Standard for Electrical Safety in the Workplace both direct workers to de-energize circuit parts to which an employee may be exposed.
After de-energizing, a qualified electrical worker is required perform a test to verify the absence of voltage. This is a complex testing process that includes a number of steps that can be cumbersome and time-consuming when using hand-held portable test instruments.
Tools that enable workers to safety monitor and test voltage have been evolving for decades. These range from non-contact proximity testers, solenoid testers, voltage detectors, digital multimeters, and an array of installed indicating devices. Each type of tool has advantages and disadvantages that may be specific to the application. Therefore, it is necessary for the electrical worker to understand any limitations of the tool he or she may be using. Selecting the proper tool is critical when verifying the absence of voltage.
Verifying the operation of the voltage test instrument itself is also a task that needs to be performed. Before beginning the absence of voltage test, it’s important to check the test instrument to ensure it is working properly – this is known as the “live-dead-live” test. The “live-dead-live” test is a best practice described in NFPA 70E. The “live” portion of the test involves using a known voltage source to verify that the test instrument is operating properly. After proving the tester is operational, you can then proceed to verify that the circuit parts are “dead” or de-energized by testing for voltage phase-to-phase and phase-to-ground. The final step is to verify that the test instrument is still operational by re-testing on a known “live” voltage source. Proving the test instrument is still operational on a known voltage source following the test ensures that there was no damage which would have caused an incorrect reading when performing the “dead” portion of the test. Similarly, OSHA has a requirement to verify the tester is functional after testing for voltage, but only above 600V.
The VeriSafe™ Absence of Voltage Tester (AVT) from Panduit simplifies the process to establish an electrically safe work condition by automating the absence of voltage verification process. The idea for the VeriSafe AVT is inspired by Prevention through Design. Prevention through Design is a methodology that focuses on preventing or reducing incidents caused by human error through design steps like eliminating the hazard, making substitutions that reduce the hazard, or introducing engineering controls.
The VeriSafe AVT is a permanently-mounted test device designed to verify that a circuit is de-energized prior to opening an electrical enclosure. With the VeriSafe AVT, the absence of voltage test is initiated with the push of a button; no additional tools are required.
More facilities are designing in advanced safety products that reduce the chances of human error and boost worker productivity. Just as the modern facility has advanced, so too has technology to verify the absence of voltage.
Learn more about Panduit absence of voltage testers here: