Ok, I live in an historical home and am required to minimize the visual imperfections {conduit} So I would like to get the highest amperage capacity possible running #6 wire so I can stick to 1" conduit, is it true that THWN-2 has a higher rating than THHN? I read it was rated at 75 amps vs 60 for THHN

  • Not how it works. That is for derating and other things. Correction factors.In the number of wires you run in pipe,The higher the insulation ,and number of wire in pipe, and size of pipe.Three or more current carrying .You have to derate wire. And if you add a lot to a pipe. I had to run #8 for a distance and as less wire was in pipe could drop down till #12 to run a 20 amp light circuit. Was #8 but could only be 20 amp breaker load . – user101687 Jun 15 '19 at 3:03
  • It will still be on a 60 amp ,breaker not 75. – user101687 Jun 15 '19 at 3:11
  • How many amps do you need? Last I heard you needed 60A. – Harper - Reinstate Monica Jun 15 '19 at 3:49
  • Okay, I understand now I think, I was going to run 3 #6 THWN R/B/W and 1 #8 G From my main panel with a 60amp double pole breaker to my new sub panel in the garage. But got confused when I read I should use a 100 amp panel instead. I still am limited to a 1" conduit. Do I still have to add a Grounding rod since its a separate building? – Will Jun 15 '19 at 14:57
  • Oh you can use any size of panel as long as it is greater or equal. I would actually go larger than 100 amp panel so that you get more spaces in the panel. Running out of space has a very inconvenient situation and it's so easy to avoid. Yes, you can feed a one hundred amp or even two hundred amp panel from a 60 amp breaker. – Harper - Reinstate Monica Jun 15 '19 at 17:49

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