NFPA 70E General Requirements — Part 2

At one time, you assumed electrical conductors and circuit parts were in an electrically safe condition unless you had some reason to suspect they weren’t. Today, you assume electrical conductors and circuit parts are not in an electrically safe condition until you prove they are.

What is that proof? All of the requirements of Article 120 are met. Those requirements are centered on lockout/tagout. In other words, to ensure the equipment is safe to work on, shut it down and lock it out. But there are some exceptions:

1. Shutting it down creates an even greater risk than working it energized [110.4(A)].
2. It just is not feasible to shut it down and lock it out [110.4(B)]. You can’t establish an electrically safe working condition, which means a hazard exists.
3. Below levels of 50V, shutting it down isn’t required if specific considerations are made and it’s determined there’s no increased exposure to electrical burns or explosion due to arcs [110.4(C)].

Some kinds of testing will require normal operation of the equipment. But when is normal operation of equipment even permitted? It is permitted only when you have normal operating conditions, a situation that exists only when all of the following are met:

1. The equipment is properly installed.
2. The equipment is properly maintained.
3. The equipment is used per instructions included in the listing, labeling, and peer manufacturer’s instructions.
4. The equipment doors are closed and secured.
5. All equipment covers are closed and secured.
6. There is no impending evidence of failure.

What about performing thermography on equipment that isn’t functioning properly? Clearly, that’s not normal. You can’t shut it down before performing the thermographic scans, and you can’t perform thermography with doors and covers closed and secured.

Further, the problems might be because equipment isn’t properly installed. For example, connections were made without using a torque wrench. Or it might not have been properly maintained because people simply tightened what they thought were loose connections. These are exactly the issues where thermography is commonly used for identifying the hotspots created at those poor connections.

Those are good points. These and other real-world considerations are why we have Article 130. Article 130 is about what to do when you don’t have normal operating conditions and the equipment needs to operate or at least remain energized. The process begins with an energized electrical permit [130.2] if either of these conditions exists:

1. Work is performed within the restricted approach boundary.
2. The employee interacts with the equipment when conductors or circuit parts are not exposed but an increased likelihood of injury from an exposure to an arc flash hazard exists.

Article 130 is tedious and complex to apply. Always try to go the Article 120 route first. Make shut it down and lock it up your preferred strategy.