To avoid negative and unsafe events, electrical power engineers recommend conducting comprehensive assessments of electrical systems every five years. Because most electrical equipment has an average life span of 20 years, it is good practice to assess the entire PDS every five years to determine the present state and deterioration rate of each piece of equipment. Also, because electrical equipment deteriorates at different rates, the inspections and risk assessments provide facility managers a firm understanding concerning the present state of their PDS and information as to where or when they may need to replace or modernize a piece of equipment or enhance equipment maintenance. Understanding a PDS’s maintenance or upgrade requirements will give a better picture of the system’s reliability and risks.
Power risk assessments done right
Frank Waterer, Schneider Electric
Work to eliminate or mitigate risks
A notable change in NFPA 70E 2018 is a heightened focus on hazard elimination. In fact, the hierarchy of risk control methods has now moved from an informational note to part of the standard’s mandatory language. When it comes to implementing safety-related work practices, the standard clearly states that hazard elimination shall be the first priority. This means that taking steps just to mitigate a hazard may not be enough to protect your employees and plant and reduce your liability.
The risk control methods essentially break down into six areas: elimination, substitution, engineering controls, warnings, administrative controls, and PPE.
If elimination isn’t an option, then substitution is the next best thing. This could mean opting to use less-dangerous equipment, such as nonelectrical or battery-operated tools. Engineering controls are next in the hierarchy and can be as simple as ensuring ground fault circuit interrupter (GFCI) protection or as advanced as changing the relay logic in your power distribution system.
Your deep dive into NFPA 70E 2018
Steve Park, Vertiv
Estimate of the likelihood of occurrence of an arc flash incident
One important change to NFPA 70E was the addition of Table 130.5(C), which states that on electrical equipment in any condition (normal or abnormal), performing infrared thermography and other noncontact inspections outside the restricted approach boundary does not increase the likelihood of occurrence of an arcing fault and arc flash incident, so additional PPE is not required. However, the table further clarifies that this does not include opening equipment doors or covers that expose bare energized conductors or circuit parts – which specifically does increase the likelihood of occurrence of an arcing fault and arc flash.
Although not specifically mentioned in Table 130.5(C), opening an EMSD cover like that on an infrared viewing pane does not expose bare conductors or circuit parts. One can thus interpret that in this instance, no PPE would be required. In this manner, the use of an EMSD and changing the work process to keep the equipment in a closed and guarded condition while performing the CBM task seems to follow substitution stage guidelines of the hierarchy of control.
Is your condition-based monitoring program current with NFPA 70E?
Rudy Wodrich, P.E., MBA, CRL, L1 Thermographer
