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opnspaces's avatar
opnspaces
Navigator III
Mar 27, 2018

Can I use 4awg wire for my inverter

I want to use my 600W inverter on my trailer. My current plan is to mount it in a box on the tongue keeping wire length to about 18 inches. On an earlier post it was suggested to use 4gauge wire for 600w. Link

My question: I have a lot of 4awg wire that I used years ago on a hot tub at home. Can I use this wire on my inverter? It's very stiff and not at all flexible like the welding cable that everyone suggests. But it's free and I'd rather not spend any more than I have to for this project. Aside form the stiffness is there a reason that I should not use this wire?
Thanks

10 Replies

  • I would not buy auto parts store battery cables. They are SAE gauge not AWG. SAE is 6 to 12% thinner.

    Also the ring terminals preinstalled on most AP store cables are steel.

    Bring a magnet.
  • What is not over-rated is how easy it is to install that wire incorrectly and put strain on the inverter terminals. Ever look to see how those are fastened to the chassis? Even my Samlex is no candidate for lots of lateral or axial tension. It has soft rope strand welding cable, positioned with standoffs so as to absolutely minimize terminal weight, and cable mass inertia. My 4024 4,000 watt on the other hand has very stout pass-through terminals albeit with standoff adel clamps.
  • IMO the "work harden" issue is overrated unless you are mounting to something that actually moves such as power to the slide or tow vehicle to trailer. Support the wire to keep stress off the terminals and prebend the wire before you connect to the terminals to minimize stress and it will be fine.

    The other issue I have with scavenging jump cable wire is the unknown temperature rating of the insulation. And unless it says very bold 100% copper wire just pass.

    For premade cables check here:
    http://www.genuinedealz.com/custom-cables?size=57
  • DrewE's avatar
    DrewE
    Explorer III
    opnspaces wrote:
    Thanks for all the responses. I hadn't considered the flexing and work hardening aspect. I might also look into the starter cables from the car parts store. Though I wonder if those are really copper plated aluminum like most of the cheap jumper cable sets.


    The starter (or switch to starter, or similar) wires I've seen have been proper copper wire, so far as I can suss out. The money and weight savings are not so large when it's a foot and a half wire assembly as when it's eighteen feet of double wire. Also, they need to actually carry substantial current to work properly.
  • Thanks for all the responses. I hadn't considered the flexing and work hardening aspect. I might also look into the starter cables from the car parts store. Though I wonder if those are really copper plated aluminum like most of the cheap jumper cable sets.
  • opnspaces wrote:
    I want to use my 600W inverter on my trailer. My current plan is to mount it in a box on the tongue keeping wire length to about 18 inches.

    My question: I have a lot of 4awg wire that I used years ago on a hot tub at home. Can I use this wire on my inverter? It's very stiff and not at all flexible like the welding cable that everyone suggests.


    While I'm always in favour of making use of parts I already have in my workshop I'll only do that if it's suitable for the task at hand. Considering that flexible, purpose designed battery / starter cable already terminated with appropriate ends is readily available in a variety of gauges at moderate cost I'd pass on stiff wire that's not really intended for the purpose. Once the weather warms here I'll be doing just this myself, replacing a flooded battery that's been sitting on the trailer tongue and connected to my inverter which is mounted in the front pass through cargo compartment with 6' of 4 gauge cable. In it's place I'm mounting an AGM battery in the pass through and replacing that excessively long 4 gauge with 18" 1 or 2 gauge starter cable. I could cut up the existing 4 gauge cables and re-terminate them again but for the minor cost of these starter cables I wouldn't even waste the time.
  • there are a ton of charts on what gauge vs length you need on the internet i would reference a few of those. I think you are also supposed to but a fuse between the positive run of the battery and the inverter.
  • I would use caution here, assuming you are dealing with building wire, NM-B, UF or maybe TFWN-2 this is not the best stuff for mobile applications, over time copper will work harden and crack if solid condutor or even course stranded conductor. At a minimum I would want something like motor hookup rate wire (MTW) to lower the risk of work hardening.
  • No, you can use it. Keep distnces between inverter and battery as short as possible. Most inverters are not classed to operate in an exterior environment so installation issues may prevail.

    You may also wish to price out two 18" lengths of new 4 awg. Average price of 4 AWG cable is about $1/ft so I would assume $3 wouldn't be a project budget issue.

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