The NATED N1-N3 Plumbing qualification is a qualification from Levels N1-N3 focusing on the theory of plumbing. This qualification meets the academic requirements for you to write your trade test once you have acquired the required practical hours. This qualification consists of one compulsory part (N1-N3 theory) and two optional practical parts, beginners level (done between N1-N3) and advanced (can be done after N3)