- Dec 27, 2005
- Kubota GL3830/GL5030
Interesting. Something I've always questioned is my plumber's installation of a hot water heater in my mechanical room. The wire length is 20', but it is on a two pole 30 amp circuit with #14 wire. The wire has never felt warm even after the water heater was on for nearly an hour following back to back to back to back showers. This is an easy one to correct, though, as the wiring is all exposed (not in conduit and not behind sheetrock) romex. Nevertheless, I've also found it interesting that the wire wasn't perceptibly any warmer when under longer-term amperage draw. Maybe I'll shoot it with my IR Fluke camera to determine how warm it is or is not getting for sure rather than gut-checking the 'feel', but I've felt warm wires before and these aren't that. Regardless, I'll change out the wire since it's easy and I know for certain not 'to code' (the ONLY thing in the house that isn't).Correct -- the ampacity ratings are based on material, insulation type, bundle/conduit type, etc, such that the wire can handle a certain number of amps and not get hot or melt. The ampacity is also affected by numbers of wires in proximity. So there are often limits to how many wires can be in a conduit or bundled together in a jacket. I have even seen some underground/wet rated wire that will have a different ampacity whether direct buried or in conduit. The end focus always comes down to keeping the wire within the temperature rating of its insulator and conductor materials.