Absence of voltage testing is a vital step in the process of verifying and establishing a de-energized state of any electrical system. As detailed in NFPA 70E clause 4.2.5., there is a specific and approved approach to establishing an electrical safe work condition with the following steps:
- determine all possible source of electrical supply
- interrupt the load current, open the disconnecting device for each possible source
- verify where possible that all blades of the disconnecting devices are open
- release or block any stored energy
- apply lockout device in accordance with documented and established work procedures
- using an adequately rated portable test instrument to test each phase conductor or circuit part to verify it is de-energized. Test each phase conductor or circuit path both phase-to-phase and phase-to-ground. Before and after each test, determine that the test instrument is operating satisfactorily through verification on any known voltage source
Read the article in the Intelligent Power Today Magazine. 2021 Issue 1
