7. If there is no marking, then turn on in turn in the socket two of any wires extending from the lamp, not touching the 3rd. Когда половина ламп загорится, пометьте изолентой включенные провода. Leave one in the outlet, and install a batch of the 2nd third wire there. If the other half lit up, then they found a second phase wire. The wire that remained during the operation in the outlet is «zero».
