As for permanently installed, it gets done all the time with UL's blessing by virtue of the fact that most of them come with tabs, ears or slots for mounting.
Yes they do often come with mounting means.
But not with ULs blessing as they specifically tell us not to mount them.
Relocatable power taps are not intended to be permanently secured to building structures, tables, work benches or similar structures,
To tell you the truth I mounted a surge suppressor plug strip to a clean room bench just last week. It's odd to me that UL feels it safer to leave it floating than fastened.
