We investigate data transmission schemes over power line channels where the source and the destination are connected by the 3-phase channels. Assuming that the same codeword is simultaneously transmitted over all channels, we analyze the decoding algorithms at the destination provided that there are 3 intermediate independent helpers who receive corrupted versions of the codeword and inform the decoder about results. If helpers are allowed to transmit the same number of bits as the length of the received vector, then the scheme is equivalent to the decoding of the codeword by joint use of its 3 corrupted versions. If helpers are only allowed to send the number of bits equal to the logarithm of the total number of codewords, the scheme corresponds to a 2-step decoding at the receiver when joint operations for 3 received versions are applied to the results of the helpers. We investigate both possibilities and demonstrate the results for the (7,4) Hamming code and binary symmetric channels.