Xantrex 6048 - DC wiring question

Dusty
Dusty Solar Expert Posts: 271 ✭✭✭
in General Solar Power Topics #1
I'm not having any luck finding an online source for 4/0 wire, and the local home centers don't have it either. I'd prefer to just purchase the length I need--3 feet for + and 5 feet for - is plenty. Does anyone know of a source? Thanks in advance!
XW6048, 3.4KW PV, Grid-Tied, always tweaking.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Xantrex 6048 - DC wiring question

    Yes, there's this place called Northern Arizona Wind and Sun. Perhaps you've heard of them? They host this forum. :D

    4/0 Wire, black or red: http://www.solar-electric.com/wc--4-0.html

    Really it should be available to you locally as well. Look for welding supply sales.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #3
    Re: Xantrex 6048 - DC wiring question

    Good source, Marc,

    And, if this installation is to be inspected for Code compliance, welding cable is often judged to be non-compliant, as it is not rated for uses other than welding (at least for cables to Inverters).

    You may want to spec the MTW (UL) cables:
    http://www.solar-electric.com/49075.html

    Am not certain that Wind-Sun is able to make custom-length MTW Inverter cables.

    I DO believe that battery interconnect cables CAN use welding cable, but, again if this system needs to be inspected, you should contact the AHJ for the exact requirement.

    Not to pick the nit too finely. Good Luck with the system, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: Xantrex 6048 - DC wiring question

    Vic, sometimes those AHJ's pick nits to the bone. Other times they don't know the difference between 4/0 welding cable and lamp cord. It's like rolling the dice. :p
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  • Dusty
    Dusty Solar Expert Posts: 271 ✭✭✭
    #5
    Re: Xantrex 6048 - DC wiring question

    Well I'll be.... I bought everything else from them. Why didn't I think about wire? :blush:

    Thanks! I'll order it today.

    Just to be safe, I'll stay away from welding wire.
    XW6048, 3.4KW PV, Grid-Tied, always tweaking.
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  • Dusty
    Dusty Solar Expert Posts: 271 ✭✭✭
    #6
    Re: Xantrex 6048 - DC wiring question

    Is 3/4" metal flex conduit large enough for 4/0 wire?
    XW6048, 3.4KW PV, Grid-Tied, always tweaking.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #7
    Re: Xantrex 6048 - DC wiring question

    Dusty,

    Great that you have been supporting the generous host of this great site.

    Generally, it is considered best to run cables such as these together on one conduit. A single 4/0 may fit in a 3/4" metal flex conduit (nice to see you using metal), and you may need to use something like 1 1/2" or even 2" to fit two 4/0 MTW conductors (odd numbers of conductors usually make better use of conduit area).

    Believe that MTW insulation is thicker than that of compact conductors such as THHN. All of my references are at another site, and most on-line data is for THHN in EMT/RGD/IMC pipe. You could find the nom diameter of 4/0 MTW, and perhaps extrapolate to some close size of THHN, perhaps. And, possibly you proposed 3/4" flex due to min bend radius. One thing to watch out for with larger "flex" is the min bend radius.

    Personally have used 2" or 2.5" 90 degree EMT Ls for inverter to battery (box) cables. Others here prob have table data for flex and MTW cable at their fingertips. Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • Dusty
    Dusty Solar Expert Posts: 271 ✭✭✭
    #8
    Re: Xantrex 6048 - DC wiring question

    Thanks Vic,

    My old 1200W, 12V inverter was connected to batteries via 1/0 wire, so I had no idea how much thicker 4/0 is! I just ordered the 4/0 cable from this site's host.

    The Midnight Solar E-panel will be arriving Friday, so there's still time to get the proper sized conduit. Thank you!
    XW6048, 3.4KW PV, Grid-Tied, always tweaking.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #9
    Re: Xantrex 6048 - DC wiring question

    Ok Dusty, Great,

    As you know the max fill per NEC is quite a bit less than the max one can cram into conduit. I have run 4 ea 4/0 MTW inverter cables in an EMT L, but knew that this was over the max NEC fill. This was a very short run and was not going to be inspected ... believe that the NEC max was prob 3 ea 4/0s. Sounds like you are having fun, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • Dusty
    Dusty Solar Expert Posts: 271 ✭✭✭
    #10
    Re: Xantrex 6048 - DC wiring question

    Thanks Vic,

    Oh yes, I'm having fun. Itching to commission the system, but not at the expense of safety. This will be a very short (less than 1') run to the battery box, and I did read that it's better to have the two battery conductors alongside each other to minimize induction loss. I'm just not sure how significant that loss is over such a short run.
    XW6048, 3.4KW PV, Grid-Tied, always tweaking.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #11
    Re: Xantrex 6048 - DC wiring question

    Running the "Hot and Return" in the same conduit and into the "same hole" in a metal box--That is a requirement for AC power. Running Hot and Return through different conduit and holes in the metal boxes will create circulating current in the conduit/boxes which can overheat the sheet metal.

    For DC, that is not really a requirement (however--for Inverters with heavy DC current ripple, I would worry that circulating currents are possible)...

    But, for best operation, I would still run +/- tightly together. That keeps the wiring impedance (inductance) to a minimum, and also reduces any "loop antenna" effects. Both keeps any Radio Frequency Interference low, and if you have nearby lightning/static discharges, keeps the wiring from receiving energy too. For computer communications cables (such as Ethernet Cat3/5 cables), the pairs are also twisted to reduce RFI issues.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dusty
    Dusty Solar Expert Posts: 271 ✭✭✭
    #12
    Re: Xantrex 6048 - DC wiring question

    Will do! Thank you for the explanation. I have the wires twisted on my XANTREX LINKLITE battery monitor for that very reason (well, actually, because the instruction manual said to do that). The MS E-panel instruction book lists the largest knockout as 2.468/.875" with the other knockouts being 1.375".

    -Dusty
    XW6048, 3.4KW PV, Grid-Tied, always tweaking.
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