Why De-Energized Maintenance (and not IR) Gives You the Most Bang for Your Buck

By Michael M. Dillard, MTS, CESCP

When I ask most facility managers what maintenance they perform on their electrical distribution system, they will usually say they do IR scans (infrared thermographic inspections) for hotspots. They are a little shocked when I inform them that performing infrared scans isn’t really the same as performing maintenance.

While these types of non-destructive tests are helpful in finding loose connections and other heat-related issues, nothing is actually being fixed when you do these scans, thus it’s not really maintenance. The beauty in IR scans (and other forms of energized testing) is that they help you to locate potential issues that will need repair maintenance to fix the problem. The majority of electrical equipment maintenance will be performed with the equipment being in a de-energized state. In other words, maintenance is performed during a de-energized service. The NFPA 70E (2021) requires this be done when at all possible.

Article 110.3 states:

Electrically Safe Work Conditions. Energized electrical conductors and circuit parts operating at voltages equal to or greater than 50 volts shall be put into an electrically safe work condition before an employee performs work if any of the following conditions exist:

(1) The employee is within the limited approach boundary.

(2) The employee interacts with equipment where conductors or circuit parts are not exposed but an increased likelihood of injury from an exposure to an arc flash hazard exists.

Article 100 defines ‘Electrically Safe Work Condition’ as:

A state in which an electrical conductor or circuit part has been disconnected from energized parts, locked/tagged in accordance with established standards, tested to verify the absence of voltage, and, if necessary, temporarily grounded for personnel protection.

Article 100 also defines ‘De-energized” as:

Free from any electrical connection to a source of potential difference and from electrical charge; not having a potential different from that of the earth.

It is also important to note that Ansi Z10 prescribes a hierarchy of controls which contain six elements, the first of which, in priority order, is to eliminate the hazard. If the hazard is eliminated, the risk is eliminated. When your electrical equipment is in a de-energized state, the hazard is eliminated for your workers or contracted workers that are servicing your electrical equipment.

Although I am a fan of energized inspections and testing, I always inform my customers that they also need to perform de-energized maintenance on their system to make it operate more efficiently and last longer; this means saving money in the long run and no pesky unplanned CAPEX costs due to repair or replacement. IR scans do not directly make your equipment last longer; de-energized maintenance does. Loose connections or parts, moisture, insulation problems, and accumulation of dust, dirt, and oil account for nearly 60% of all electrical distribution system failures. (Based on Hartford Steam Boiler claims data) Guess when all of those aforementioned problems get resolved? Yup, you guessed it; these things are taken care of during a de-energized service. Not only that but NFPA 70E (2021) assumes you have properly functioning equipment and that without maintenance the results of your arc flash risk assessment are technically not valid.

Basically, all the things that you need to do to your system to increase its overall life expectancy will happen during de-energized maintenance. This is why I say it’ll give you the most bang for your buck.

Article 130.5 (G) states:

The incident energy analysis shall take into consideration the characteristics of the overcurrent protective device and its fault clearing time, including its condition of maintenance.

If you have switchgear or motor control centers (MCC) at your facility, this is where you’ll primarily want to focus your de-energized maintenance efforts. As these are the critical components of your electrical distribution system, inspecting and testing the main switchgear and MCC offers you the biggest value for money spent. And while a de-energized service will require a greater level of planning and coordination (amongst yourself, your tenants, and possibly the utility company) and be more costly than energized testing, the NFPA 70B (2019) recommends this be performed every 3-6 years. Whereas energized testing is recommended every year. Thus, it’s much easier to work it into your budget.

Here’s what sort of work can typically be performed during a de-energized service (aka power outage):

  • visual/physical inspections
  • cleaning
  • lubrication and cycling of protective devices
  • insulation resistance testing
  • contact resistance testing
  • primary injection testing
  • retightening of loose connections (these are real energy wasters which many times will show up as increased electrical costs on your utility bill)
  • transformer oil testing

If you still haven’t drank the de-energized maintenance Kool-Aid yet, here are a couple more shameless plugs for doing it:

  • Bolted pressure switches (commonly referred to as Pringle switches) will usually get lubricated and cycled during this service. It is a well-known fact that lubricant in most unoperated equipment turns to “glue” in five to 10 years. What if you have an emergency that requires you to operate the main switch and it’s frozen in place? I can’t tell you how many times I’ve seen this happen over the years. The facility managers were not happy campers.
  • Circuit breakers malfunction over time and need maintenance—30% after three to five years of service, 50% after seven to 10 years and 90% after 17 to 20 years (according to a major petrochemical company study).

In closing, energized inspections (like IR) have some value because they help you to locate ongoing electrical issues with your equipment; again, I am not telling you that you don’t need to perform these types of valuable inspections. You do need to perform them to identify the problems that need fixing during an outage. Otherwise, if you just perform de-energized maintenance (and you didn’t identify existing problems with some sort of an energized inspection), you would be sending your electrical contractor into your equipment blind. There may be existing problems that never got identified. This means an extra outage and more money spent. I’m just saying that nothing is going to actually get fixed during an IR inspection. It’s a nice check off your maintenance honey-do list but if you seriously want to make your equipment safer and last longer, then you must start performing de-energized maintenance…now.

Michael M. Dillard, MTS, CESCP is the Regional Director, Senior Consultant with American Electric (www.americanelectric.com) in Hawaii. He is a champion of preventive maintenance and an all-around great guy. He can be reached at mdillard@americanelectric.com.

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