I recently saw in a sefer on Hilchos Yom Tov that one should use a shinu when carrying on Yom Tov (outside an eiruv). I saw that is an open shulchan aruch in siman 510 seif 8 that says it. I never heard that halacha before, so I looked around to see what the practical application on the halacha is, but I didn’t find much on the topic. What is practical application of the halacha? What things require a shinu when carrying on Yom Tov?
The Shulchan Aruch is only discussing carrying large items, like a case of soda, and only if they are being carried outside in a public place. The reason for this halacha is that although we are permitted to carry things that are needed for yom tov, carrying large items in their normal fashion looks you are transporting things and considered uvdin dchol (weekday like and not in the spirit of the day). Therefore if one has a number of bottles to carry, it should be taken either only two bottles at a time, or carried differently than the regular way that they are carried. The Shulchan aruch ( sief 10) does say that if there is a need, such as when one has guest waiting, that it is permitted to carry it in the normal manner. Additionally, this will not apply when carrying in a semi private domain, such as the courtyard of one’s building etc., but only when going in the street etc.
Yom Tov Khilchoso 13-65.