This morning ,I got a three-phase plug with 6 wire terminals( see pictures), L1 , L2, L3, N/W, Earth, and a "pilot" terminal, I don't know what 's the "pilot" terminal use for , for testing or other purposes ?
This picture was taken in my workshop , and these three-phase plug mainly used for connecting equipment like water pump , electric welding machine to the AC 380V distribution box on the wall,no control circuit inside the distribution box , and controlling the power supply only by RCD
If it's a CEE Standard plug, the Pilot contact is for operating a Contactor, so the plug contacts don't wear off when connecting or disconnecting under load. See here, chapter 4.1 https://en.wikipedia.org/wiki/IEC_60309
Hi, andey. This is a "MENNEKES" plug with made in Germany, I have seen the fully detailed explanation about the "pilot" contact on wikipedia website, thank you for your help!