I understand how to do single phase ze and pfc,the pfc has 2 settings l+e and l+n settings take the highest of the 2 readings for pfc.On a 3 phase installation armoured I am ok doing the ze but what happens about the pfc someone said its only required on the l+n setting or should I be doing both l+n plus l+e and whats the rule about doubling the value you get?