Opening balance equity account is only used when you first start using QuickBooks and make the first entries, bringing forward balances from another accounting system or from tax return or bank account depending on where you tracked your previous accounting activity prior to QB. 

Personally, I have never used that account since equity is an ongoing account for life of business.

Entry for a line of credit, where you received Cash, would be a Debit to Cash and Credit Liability. 

Liability is long-term if it will not be paid within 12 months, short-term if paid in less than 12 mo.