• Electrical code violations
• Loose or poor connections in your electrical system that may be arcing (when an electrical current jumps between normally non-conductive current, creating a plasma discharge or a spark)
• Connections between the neutral wire and the electrical ground wire that divert the neutral return current to another path, such as water pipes, gas pipes, heating ducts, air-conditioning Freon lines, grids for dropped ceiling panels, metal studs or conceivably any metal in your home
• Switches that are old, worn or poorly made that may be arcing
• Neutral wires whose insulation has been pinched or punctured, causing an inadvertent connection between neutral and ground wire
• Tree branches that scrape or bump overhead wires (your utility company may trim them for you)
• Dimmer switches
To fix these problems:
• Talk to your electrician about harmonic filters or line/power conditioners, which are recommended for the protection of expensive electronics such as home theater systems. They basically suppress voltage spikes coming from the utility power system, and as an unintended benefit clean up dirty electricity in some frequency ranges––filtering out transients and harmonic distortions.
• Contact your utility company to check the power lines that run into your home to make sure all connections are secure. Some may be so old, worn and corroded that the flow of return current is impeded.
• Install a radio frequency (RF) filter on your phone line, which can also bring dirty electricity into your home. RF filters are designed to reduce high-frequency white noise on phone lines, which can be picked up via the air or on electric-utility ground currents.