Growing up working for my father’s construction company, there was one saying he used to say, “Just because you can, doesn’t mean you should!” This was usually Dad’s go-to statement when talking to one of his guys on the job site when they did something unsafe or risky. Today, this adage still applies, even more so when it comes to electrical inspections with ultrasound devices. Just because you have a contact module in your kit doesn’t mean you should use it to contact energized gear when you hear something with your airborne module from the seam, vented opening, or ultrasound port!
If we look at the Hierarchy of Controls from NFPA 70E, the first step is the Elimination of the hazard by de-energization of the equipment. However, Condition Based Maintenance (CBM) inspections like ultrasound require the equipment to be energized, so we move to the second stage called Substitution or “Safety by Design .” The question is, can we redesign the work task and/or the equipment in such a way as to eliminate the hazard without introducing any other new hazards? The use of Infrared Windows and Ultrasound Ports is the best method for Substitution the in the CBM realm since Infrared and Ultrasound have become a go-to test method for the detection of electrical fault conditions of closed panel energized assets.
Without the Substitution (Safety by Design) Devices in place, it can be next to impossible to test using Infrared Cameras or Ultrasound Devices. With the enclosure panels in place, the inspector may still be able to use an airborne module and trace the seams or air vents to listen for ultrasound anomalies. Remember that most electrical equipment should have no discernible noise emanating in the ultrasound spectrum. In addition, the challenge with this “seam sniffing” method is that diffraction of the signal can cause issues with the signal’s amplitude being increased as it bounces out of the seam and increases the decibels. Decibels should never be used as a trendable value for determining required intervention action on electrical assets. Sound wave analysis of the anomaly is the only way to truly determine what fault condition is present in the gear.
When ultrasound is detected coming from the asset, it should be tested further, but with the panel being closed and without having IR Windows or Ultrasound Ports, there is no way to safely test this while energized. So, the gear will need to be de-energized and then opened to look for visual indications of corona, treeing or tracking. Once these visual indications are found, corrective action can be determined, which may include cleaning, component replacement, or re-cabling.
The inspector should almost never perform an open panel energized inspection using ultrasound devices or infrared cameras, as this would be deemed a last resort per the Hierarchy of Controls. In the event that this is deemed the ONLY way to perform the work, the personnel have the appropriate training, a job safety plan has been created (including planning for human error), and if the equipment’s arc flash rating has been gauged to be one that PPE can be worn to perform energized open inspections, there are still a few things that will need to be heeded.
- The CBM Analyst should never wear the headphones for their ultrasound device under the hood of the Arc Flash Suit but rather hold the headphones to the side by their ear on the exterior of the suit.
- Even when wearing PPE, they should also never break the plane of the opening of the gear. Restricted approach boundaries, as defined in the NFPA 70E tables [130.4(D)], should always be maintained.
- They should especially never use the contact module or even rubber/plastic focusing probes or range horns to touch energized equipment to locate or listen to the anomaly. It only takes one time for it to be your last time ever!
So, a CBM Technician should only very rarely open gear while it is still energized to perform an airborne ultrasound inspection. It has been brought to our attention that there are instances where a CBM Technician has actually swapped out their airborne module and used their contact module to make physical contact with the open energized gear, and we cannot stress enough that this is an unsafe act and should never be done!
We at IRISS cannot stress enough the importance of safety for electrical personnel, and this is why we created the IR Windows and Ultrasound Ports to help protect those doing electrical inspections by minimizing the risk of this CBM data collection task. Being able to visually look with your eyes and IR Camera affords you a safer view of what’s occurring inside the equipment, and the addition of the Ultrasound Ports gives you the best sound quality of any possible electrical anomaly without the effects of Antagonistic Ultrasound, Diffraction of Signal or inability to achieve the Critical Angle of the anomaly.
About IRISS Inc.
IRISS Inc. is the global provider of Electrical & Mechanical Asset Management Solutions that increase safety and reliability while decreasing costs, human error, and injuries/fatalities in the inspection and maintenance process. Through unmatched research and development, we harness advanced technology to design and manufacture reliable Infrared, Ultrasound, Intelligent Asset Management, and Wireless Temperature Monitoring solutions.
