A Home Equity Line of Credit is money in a loan account that can be used as you need it. You can use any portion of it at any time and pay it back at any time. The interest rate is usually variable and is tied to the prime rate. Other types of second mortgages, such as the Home Equity Loan, and 125% value loans are closed end loan products. You borrow a lump sum and pay it back over a period of years with interest. The interest rate for these products is fixed.