In “Family Feud” TV gameshow fashion, if we asked the general public, “What is the best way to protect yourself from electricity?” the number one answer would be: “Turn it off.” Even within the electrical industry, the answer typically is the same — turn off the power.
It seems that almost every initial safety audit results in finding someone working on something de-energized with the assumption that it is safe because “I opened that disconnect switch right over there, so I know it is de-energized.” However, for conductors to truly be safe, there are more steps to follow than just simply turning off the power.
Section 120.2(A) of NFPA 70E-2018 states “Electrical conductors and circuit parts shall not be considered to be in an electrically safe work condition until all of the applicable requirements of Article 120 have been met.”
Per Sec. 120.5, an Electrically Safe Work Condition is established through an eight-step process:
1. Identify all potential sources of electrical energy.
2. Open disconnecting devices for all potential electrical sources.
3. Whenever possible, visually verify the disconnect devices are open.
4. Release stored electrical energy.
5. Release or block stored mechanical energy.
6. Apply lockout/tagout (LOTO) devices.
7. Verify absence of voltage on all phases using the live-dead-live method.
8. When applicable, apply appropriately rated personal protective grounds.
If any of the eight steps that are applicable are not complete, then the circuit or circuit part is not in an electrically safe work condition and should be treated as an energized conductor. Therefore, de-energized does not necessarily mean that the conductor is safe; an electrically safe work condition must be established.
Northcott is a professional engineer licensed in the state of Tennessee and a senior power engineer with Jacobs Technology, Inc., in Tullahoma, Tenn. He is also an NFPA 70E compliance subject matter expert, a principle member of the NFPA 70B Committee, electrical safety trainer, certified maintenance and reliability professional, and certified reliability leader. He can be reached at [email protected].
