N.J. Stat. Ann. § 18A:22-25

The board of education may, after July 1 and before January 1, borrow a sum not exceeding one half of the amount appropriated for the current expenses of the schools and for the repair of schoolhouses under its control, and execute and deliver promissory notes therefor, and pay the amount so borrowed together with interest thereon, at a rate not exceeding 6% per annum.