Is your three phase outlet connected correctly now you can be sure incorrectly connected outlets can lead to serious damage to the connected equipment the voltcraft st 32b 3 phase socket tester cee 32a is intended solely for a quick diagnosis of cee power current sockets on the public alternating current grid max 415vac which are secured with 16a or 32a fusethis device recognises interruptions to the three phases the neutral wire or the earth additionally the rotating field clockw