AM2S - Section B: Live Testing: Live Polarity at Distribution Board

In this practical electrical testing tutorial, we demonstrate how to carry out live polarity testing on the incoming supply of a three-phase installation before energising and testing the final circuits. The video begins with important safety reminders, including the requirement for apprentices and delivery staff to wear appropriate PPE in an official workshop environment. The practical examples shown are completed within a controlled teaching environment. The tutorial covers the correct sequence of checks required before introducing the supply onto the installation, including maintaining isolation procedures and ensuring the system is safe before carrying out live testing. The process of restoring the incoming supply to the distribution board is explained, along with the importance of keeping appropriate isolation in place while completing the initial verification tests. Using a suitable voltage indicator, the video demonstrates how to carry out a series of live polarity checks, including: Testing between phases (L1–L2, L1–L3 and L2–L3) Testing each phase to neutral Testing neutral to earth Testing each phase to earth Confirming expected voltage readings on a three-phase supply Understanding the importance of arranging tests correctly to maintain confidence in test results The video also explains good practice when using voltage indicators, including checking equipment condition and understanding when proving the device before and after testing may be beneficial. Particular attention is given to the neutral-to-earth test and why a tester should be verified if there is any doubt that a zero-voltage reading is genuine. Finally, the video demonstrates how the completed results are recorded on the schedule of test results and explains how this polarity verification forms part of the wider inspection and testing process before moving on to phase sequence testing at motor terminals. This tutorial is ideal for electrical apprentices, learners preparing for practical assessments such as AM2, and anyone looking to improve their understanding of safe electrical testing procedures. Topics covered: ✅ Three-phase live polarity testing ✅ Incoming supply verification ✅ Voltage indicator use ✅ Phase-to-phase voltage testing ✅ Phase-to-neutral testing ✅ Neutral-to-earth checks ✅ Recording test results ✅ Electrical inspection and testing procedures #ElectricalTesting #ElectricalApprentice #AM2 #InspectionAndTesting #ThreePhase #ElectricianTraining #ElectricalInstallation #VoltageTesting #LiveTesting #ElectricalSafety