At a recent level I ultrasound certification class one of my students mentioned that had he known, ultrasound was useful for scanning 4160 gear...he would had been using it for that. I hope that this was only a suggestion from among his immediate piers or a misunderstanding on his part.
Is there a concensus among infrared thermographers that scanning 4160 with airborne ultrasound before opening a panel or during inspection is not necessary?
Your opinion would be appreciated.

I'm glad to say that the practice of "scanning" with ultrasound detection equipment prior to opening and enclosure is more and more widely used.In fact, the next version of ASTM's standard on inspection of electrical equipment, due out early next year, will address this directly and make the recommendation that it be done.

Thermally yours,

John

My opinion - If you are doing ultrasound inspection anyway, then you might as well scan near openings before you open the door. But ultrasound is as far as I know in its infancy and it’s ability for reliable detection of any kind of electrical faults has not been shown to my knowledge (although I am not that familiar with ultrasound and welcome additional info) and even more limited before the door is opened.

Therefore I think there may be some false sense of security to think that any great personal protection is offerred by scanning before you open the door. Personal safety will rely primarily on proper PPE and practices (for example standing aside while the door is opened). That said, if it makes us even a tiny bit safer, then it's a great idea... I just wanted to point out the limiations.

Amplifying electripete and previous posts of mine - add the lack of a quality 3rd party ultrasound certification and the "sense of security" is on even thinner ice.

Until vendors let go and practitioners increase the demand for valid certification - we will continue to lack the professional credibility that is granted to almost every other area of business specialty.

Jaded additional comment - I cannot wait to meet a certified ultrasonic tech that is hearing impared.

Terry O

Terry,

Believe it or not, I recently had first hand experience of witnessing a gentleman with ear plugs inserted while monitoring a bearing and couldn't hear the obvious noise the bearing was making that I could hear without earplugs!

By the way, I strongly encourage the use of ultrasound before opening MCC enclosures. This technology is mainly practice or using it frequently after a level 1 course of understanding is achieved. It will detect corona on high voltage systems.

I have recently purchased a corona camera due to the amount of corona I have been detecting with my ultrasound, wanting to put a picture with a sound. I think the big concern in scanning any metal clad with ultrasound prior to opening it up from what I understand is the potential for flashover is greatest when opening the door due to atmospheric changes. I also learned in the corona course is that corona can be detected in as little as 1,000 volts however I thing the bigger concern is the arching or tracking which are advanced stages of electrical failure and are more easlily heard with the ultrasound than waiting to open the door and witness this first hand. even though im sure we all have our arch flash suits on its like wearing a shark suit who wants to be the first one to see if it works.

Craig

Pete standing on the other side being a mechanical guy with no infrared outfit (yet), I would combine the two. Corona is phenomenom, that implies that the air molecules around the conduct are vibrating faster. This can be heard with an ultrasound gun using a parabolic concentror disc to listen at "heights". Since there is no heat involved yet, it will only be detected by infrared when the material damage is in an advanced stadium. The ultrasound gun can be considered an "early warning" system in the case of corona or arching.

Any estimate on how early that warning could be get?

Since we don't have the thermographic equipment, we cannot make the comparison. In another part of our company, a survey was conducted by a "foreign" Contractor, using both Ultrasound and Thermography on the distribution network.

In other words corona can be heard, before the effects are visible (arching, heat generation etc..), but don't ask me how much time between the two, waiting also for some "war" stories

By the way, what is a 4160?

4160 Volts.

Shocking!

Terry O