What authority governs modifications to UL listed equipment?

[tom baker]

there is no general legal requirement that anything have a UL listing at all.

In washington state our electrical laws require product listing.

 

[weressl]

..., UL is about manufacturing equipment for safe operation...

..for the specific purpose that the testing is identified.

It is important to understand that a UL label does not signify that the equipment is safe under all conditions of use. UL test to the conditions that are specified by the manufacturers User/Installer instructions and instructs the Manufacturer to amend the manual according to the test results. Ex.

How often do you have an inspector asking for a Manual to verify the above? Or are they so knowledgeable that they do not need to?