Hello. For those still wondering about the exam and how difficult it is, let me tell you from someone that has no formal engineering experience and has worked strictly with low voltage. Our company received UL 508A certification in 2012 under the leadership of an electrical engineer whom is no longer with our company. We have built the same 3 different cookie cutter OEM panels since then with little or no variation to each build since receiving certification. I am not an engineer nor have any high voltage experience.
From my perspective, this exam was frustrating. In my opinion, the 508A standard is written by engineer's for engineer's and can be difficult to comprehend if you do not have any prior working knowledge, education, or training in electrical engineering. It constantly refers to other parts of the standard that will have you flipping back and forth constantly. You can study the standard all you want it probably will not help you when it comes to the formulas required to figure out the high voltage or the sccr questions.
Not being able to know which questions I got wrong was cruel on UL's part. I would have liked to have known just to look up the answers on my own, as opposed to being given the answer or have to study the part of the standard all over again. We are paying them after all, to ensure the standard is enforced. Now we are paying them to certify and employee as an MTR to do the UL inspectors job?
In my frustration and disappointment in not being able to pass the exam, I could very well see some people loosing their job because they could not pass this exam, whom are much like myself. Fortunately, my company has decided to switch standards to 60947, which does not require an exam or MTR certification.
Just my thoughts and gripes on the 508a exam. Moving on.