spell casting imbued items and encumberance

[Omnirizon]

my first impression was that items with a castable spell do not incur encumbrance upon casting that spell. I then realized this might be a bit naive. So how does encumbrance work with these items?

Will casting their spell incur the "spell casting encumbrance", or just basic encumbrance, or no encumbrance at all?

note: i could test myself, but i'm feeling a bit lazy, and thought someone might know off hand; plus others can benefit from the wisdom. I suppose I'm pulling out some "forum capital" on this one, not that I have any [img]/threads/images/Graemlins/icon41.gif[/img] [img]/threads/images/Graemlins/icon41.gif[/img] [img]/threads/images/Graemlins/icon41.gif[/img]