It's a miracle the blessed things are listed at all. Indeed, were it not for the 'surge suppressor' versions, and the universal use of computers in the workplace, I'm fairly confident that UL would never have agreed to list any sort of 'power strip.'
I've said it before, but it bears repeating ... if nothing else, to give everyone a peek 'behind the scenes' at UL.
Though UL is staffed almost entirely by engineers and trade school grads, every man jack among them thinks he's smarter than mere electricians - let alone manufacturers and homeowners. Why, they can read a code book, so they're experts! OK, I exaggerate a bit, but the hubris is common enough to set the stage.
Power strips are seen simply as "wrong." In their opinion, power strips are nothing but substitutes for fixed wiring. Used away from home, power strips make it way too easy to violate the 90-watt receptacle load calculation of a circuit. That's why UL insistes it be difficult to mount them. As far as UL is concerned, there is no legitimate use for a power strip. If you need one, you really need to call an electrician and have him 'do it right.'
Besides, there's a listed alternative ..... plugmold.
We'll ignore the fact that UL's facilities have thousands of power strips in use - and have since long before the things were listed. We'll simply observe that, depending on the specific department, the power strip was often considered a poor substitute for a 4-square on the end of an extension cord. Some departments insisted on the 4-squares.
So, it's no surprise that when UL was forced (by reality) to recognize power strips, they piled on as many restrictions as they could.
