DC battery cable NEC question

I am preparing plans to be submitted for solar grid tie in system build around Xantrex 6048 with 48V. Would like to get confirmation if common #4 600V rated thin stranded welding cables are approved to be used in order to connect battery bank to Dc disconnect box and inverter?

Or should I ask if there is specific NEC rule that would prohibit use of welding cable in DC circuit at 48V?

Comments

  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    Re: DC battery cable NEC question

    The cable itself would not be the problem, it will be the termination of the ends. You would need crimped lugs rated for welding cable.

    Quote from the NEC:
    Flexible, fine-stranded cables should not be used with terminals or lugs 
    that have a setscrew or screw mechanical attachment. 
    These terminals and lugs (also found on circuit breakers, fuse holders, and PV 
    equipment) are not generally listed for use with other than 
    normal 7, 19, and 37 stranded conductors. Appendix K presents additional details.
    
  • SkiDoo55
    SkiDoo55 Solar Expert Posts: 414 ✭✭✭
    Re: DC battery cable NEC question

    To be Code compliant you would need to use wire types with a NEC rating THW RHW and UL ratings types and these are avialable in fine stranded but you would need to acquire the correct crimp terminations and crimp tools unless the inverter and DC disconnect terminals are rated for fine stranded wire. If they are screw type they would not be rated for fine stranded wire.

    Welding and automotive battery wire don't meet the NEC for ratings

    Not looking for FLAK!!

    Would Welding cable work - Yes if properly terminated.
    Is It CODE Compliant - No!
    GT3.8 w/4600W Trina 230W, TX5000 w/5000W ET-250W, XW4024 w/1500W ET-250W, 4 L16, 5500W Gen. (never had to use) Yet!!
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: DC battery cable NEC question

    Not to mention that #4 wire for battery wiring on an XW6048 is way too small.

    More like 4/0 (0000 gauge)
  • SkiDoo55
    SkiDoo55 Solar Expert Posts: 414 ✭✭✭
    Re: DC battery cable NEC question

    Your are correct, with in-rush currents to start inverter/loads etc. and safety margin's that would be a good size to choose. Looks like a 131A DC current at rated power. #4 wire would make a nice night light for a few seconds before it melted.
    Sure glad I don't need batteries for my system. Thought about a small bank for back-up, but for the few times I am without power each year if it goes out at all I will just run generator.
    GT3.8 w/4600W Trina 230W, TX5000 w/5000W ET-250W, XW4024 w/1500W ET-250W, 4 L16, 5500W Gen. (never had to use) Yet!!