Why is the First LIVE Electrical Test so Important.. In the video UK electrician Marcus is carrying out the first live test according to BS7671 re-check supply polarity. Using an approved voltage indicator conforming to GS38 Marcus identifies a problem. On investigation the issue is in the cable supplying the consumers unit. Once the fault is corrected the supply polarity is checked again and confirmed before carrying out further live tests. Videos are training aids for City and Guilds (C and G)

How to Find Incorrect Supply Polarity Testing and Fault Finding Live Testing Single Phase 230 Volts How to find incorrect supply polarity with an approved voltage indicator. The first live test in BS 7671 is recheck supply polarity it is so important and in this video Marcus demonstrates how to prove supply polarity of a single phase 230 volt AC supply in a domestic dwelling. Using a proving unit and a voltage indicator we show step by step how to carry out proving polarity of the supply test. �