Section 199A, rental property, Trade or Biz, Self-Employment Tax

[John Na]

If I claim 199A for my 4 properties, and claim them as a 'trade or biz' only for 199A purposes. Do I now owe Self Employment Tax on my net rental income (which was passive for me in the past)?  I have seen both sides claim rental properties are / aren't a 'trade or biz' for 199A.  My biggest concern is if I 'elect' it as a 'trade or biz', what Code section specifically states it is NOT subject to self employment tax?  Thanks.