Measurements of the radiated electric field and the common mode current from the in-house broadband power line communications in residential environment

In Japan, in-house broadband power line communications (PLC) are regulated only in terms of the commonmode current (CMI) measured using an ISN with LCL=16 dB, DMZ=100 Omega, and CMZ=25 Omega. However it is not yet verified that such a regulation could suppress the radiated electric field strength (REF) at a distance of 10 meters below the ambient noise level (ANL). We have investigated the CMI, the differential-mode current (DMI) and the REF caused by the various commercial PLCs in a residential environment, and found; (1) the REF could exceed the regulation target as well as the ANL by more than 20 dB even if the CMI satisfies the regulation, (2) the DMI is 40 dB larger than the CMI, (3) no causality is found between the CMI or the LCL and the REF, (4) the CMI along the power line could exceed that measured at the PLC adapter by more than 20 dB, and (5) the regulation target is 10 dB larger than the ANL below 15 MHz. It is concluded that the regulation has a serious flaw, and could not suppress the REF below the ANL.