[RE-wrenches] Multiple wires on Breakers

[Ray Walters]

Greetings wrenches;

I just watched a video from Midnite Solar, where they avoided double 
lugging a breaker by using uninsulated ILSCO taps.  I've used these taps 
before as well, but never felt it was an optimum solution, as it leaves 
quite a bit of uninsulated metal in close contact with the adjacent pole 
( on a 2 pole breaker)  I was also under the impression that some 
breakers were rated for 2 wires, such as Square D QO,and QOU breakers.
My question is this:  are any breakers actually rated for 2 wires, and 
if so any that are used in the solar industry?  I know that stud type 
breakers (like Outbacks) can have multiple lugs on the same stud, or use 
a double barrel lug.

Thanks for your help,

Ray Walters