Power line communication is synonymous with powerful dirty electricity.  I have found filters to be useless in mitigating the DE from it.  The very low frequency type PLC used in the USA utilize frequency too close to the 60 Hz signal to be filtered out.   TWACS power line communication/meter is so powerful that the signal can be stopped only at the substation, so it remains on the house wiring even when the breaker is off.  It causes fluctuating electrical and magnetic fields, wiring to become antennas, and travels into the soil. 
 
Here's excellent information on power line communication - written by an electrically sensitive engineer:    http://www.eiwellspring.org/smartmeter/TWACS.htm
 
http://www.eiwellspring.org/plc.html