There is a company that makes a harmonic filter that just clamps over feed wires coming into a service entry panel (commercial or residential). It's just a two piece hockey puck type of thing with a center hole. You just unscrew the two halves, place it over a line, and screw it back together. Sort of like a big ferrite bead.
Would something like this need to be an approved device, even tho it has no connections? I know most items covered by the NEC must be approved, which usually means UL has tested them for safety in their intended applications. If "approval" would be required in a case like this, would it be as simple as just a flammability test?
Would something like this need to be an approved device, even tho it has no connections? I know most items covered by the NEC must be approved, which usually means UL has tested them for safety in their intended applications. If "approval" would be required in a case like this, would it be as simple as just a flammability test?
