Re: Section 110.14(A)
Manufacture's instructions are always a consideration in product liability issues. And UL can indeed have it both ways; they write the rules on how they are willing to certify a product's use.
As an design engineer, I can only state that, if a product performs as it is certified and is installed as per that certification, it will perform safely in my design. I am usually qualified to say it is installed per the certification, but I am not qualified to say that it will perform properly. That is left to NRTLs or the manufactures, if necessary.
Both over and under torquing are potentially dangerous. I have found over-torquing more common.
I have never been an "official" AHJ, but I have never had a problem having my construction crews properly torque connections. Fairly early in a job I simply ask them what the torque requirements are. If they know, I ask them to show me how they did or intend to do it; if they don't know, I still ask the same question and essentially remind them of 110.3(B). Once we establish how it is to be done, I review enough to feel confident. It rarely takes more than a single inquiry and I've run jobs with literally millions of terminations.
There are enough "free wheel" torque wrenches and screwdrivers out there that checking for over torque isn't that difficult.
Robert B. Alexander, P.E.
"I know that you believe you understand what you think the NEC says, but I am not sure you realize that what you read is not what it means." (Corollary to Charlie's Rule)