If the loan is secured by your rental property, the mortgage interest is reported as a Rental Expense.
Note that if any portion of the loan proceeds are used for something other than the rental property, the portion of interest allocable to loan proceeds not related to rental use generally cannot be deducted as a rental expense. Chapter 4 of Pub. 535 explains mortgage interest in detail: https://www.irs.gov/publications/p527/ch01.html
The interest can't be deducted on Sch A if it isn't secured by the primary residence.
It's not deductible on E but could be taken as investment interest on A but not deductible for your primary residence because the interest isn't secured by your primary residence.
Can I deduct interest on a Sch E (Rental Property) if I used my PRIMARY RESIDENCE ELOC to purchase the rental property?
The ELOC would be used exclusively for the rental property.
I cant seem to find a concrete answer to this question:
I have an ELOC on my primary residence.
I want to use that ELOC to buy a rental property. That ELOC would be exclusively used for that purpose and not used for anything else.
CAN I DEDUCT THE INTEREST ON SCHEDULE E?
Tracing rules apply if you get a HELOC on the primary residence and use it on the Sch E ...