Disruptive noise (current harmonics) and heat is created by modern electronics and appliances. In simpler times, motors, pumps, appliances, and other electrical devices were either on or off. These devices didn’t generate harmonics. Our modern electronics and appliances, on the other hand, draw variable energy and create noise and heat. Technically, harmonics happen when non-linear loads are connected to your electrical system. Any device that converts AC power to DC (high frequency) power is non-linear and creates harmonics. This includes just about every modern device in your home or business today. The culprits are literally all around you. In fact, if the power supply (transformer) for any of your electronics has ever been hot to the touch, you’ve experienced harmonics.