I used this ballast to upgrade an old fixture that originally had a starter motor. "Immediately" is good! Because this ballast is completely encased in plastic, it's sort of "double insulated," which was a plus for me, since the original cable for this light only has two wires. If I were to put a metal-enclosed ballast in this old unit, I would replace the original cord with a three-wire cord with a grounded plug. Very happy with this purchase.