I just did a search on split bolt, aluminum, and UL, and it looks like
you must have been refering to just the link that I provided above,
since this page for example lists split bolt connectors designed for
joining aluminum to copper and it says that they are UL and CSA
certified:
http://www.gardnerbender.com/whats_n...onnectors.html . So
I've just answered my own question as to what you were refering too ...

Thanks,
Harry

P.S. Maybe I should start a new thread about this whole idea of using
larger connectors with aluminum wire ... since this is totally off
topic from where this thread started.