I may be wrong, but I don’t see the OK to use (2) CU conductors on that breaker, just the conductor size limitation.
You have to know the breaker style…as was said it can be very hard just not impossible. As for the BOOYAH…man I just wanted to let that out as it is almost the weekend.
Actually I am assuming that Robert added that to the list and validated…as I am only able to validate with knowledge of the Eaton and Square D and Siemens…I was just hoping to add GE to the list.
In reality and since I know manufacturers very well and how competitive they are…if one company has them the others will also…trust me (or not) but that lug shown has two separate insert points with conductor serrations…which tell me if they are both the same size conductor that it will torqued evenly.
I posted that photo because I’ve been told by someone (who checked the UL listing) that the CB in the photo is NOT listed for two conductors. Seems strange because two conductors terminated just like in the photo would seem to make a better connection with the U shaped clip applying equal pressure to both conductors but it would need to be tested and listed that way.
Maybe someone with access to the UL white book can confirm this. 
Interesting enough…I may take AWAY the BOOYAH for good ole GE because nothing in their literature states its use while lug configuration seems to promote it. Good news this is a bolt on and you wont see it in residential applications…so discount that BOOYAH.
Dang you Robert…lol
Actually the Whitebook is silent on the subject in terms of molded case circuit breakers…hmmm…I have access to all UL standards…let me check the UL standard 489 and see what it says…
Ok…here is what UL 489 says -
9.1.2.8 If a terminal is acceptable for the connection of more than one conductor in the same opening and is intended for such use, the marking shall indicate the proper connection. Location Category C.
The same opening is what will throw ya…is a saddle back the “same opening” or two separate openings. Let me read on…
Plot thickens - I just emailed my buddy who works for GE (NEMA Contact) and he said 2 conductors of the same size is fine on the THED113020…HOWEVER… when I look at the UL Standard i believe he is incorrect (opps…don’t tell him I said that)
I believe it does have to be marked on the device but where…anywhere but the rear…
“Category C Marking may be on any convenient location, except on the rear.” which is straight from UL 498 so BOOYAH…remove GE from the list (at least on this model) even if it looks perfectly fine…yeah…I guess it is not so easy…lol
PS…I dont like GE breakers so thats my defense…lol
OK…so I take it back…it’s not easy…still not impossible and now I am tired of reading UL 498…to which I wish to burn it.
All hail…Schneider and Eaton…
Paul, do you (or anyone else reading this) have a photo of an Eaton, or Siemens, breaker that allows two conductors? The Square D brand are easy to determine. I’ve read many time that Siemens and also Cutler Hammer make one but I’ve yet to find one from either.
But the OP is about a panel that allows a double lugged neutral.
I don’t know about Eaton or Siemens, but here is the Cuttler Hammer breaker that accepts two conductors.
Thanks Brad
I threw this one out there because I would guess that 100 out of 100 (including myself) would automatically say that the CB does permit two conductors as shown in the photo.
The QO Style Square D has a little diagram on the breaker itself.
Even though it may be allowed, I still suggest to my clients to separate the circuits to avoid “nuisance tripping”.
yeah…it kinda was answered so the discussion move on…lol