PV Cable Alternatives

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solaris3000
solaris3000 Registered Users Posts: 24 ✭✭
in Solar Beginners Corner #1
Hello all, Here's my situation I'm moving into a new home and need to relocate my three 200 watt solar panels, batts,Inverter and control panel.



In the new home I need to run(20 Meters) the PV cables from my roof, thru a conduit down to the first floor where all of my Solar equipment will be mounted. ie charge controller, batterys, inverters, etc,,etc,,

Can I use a Speaker wire (Monster cable) for this or will the power loss be too great to use anything other than PV CABLE.

Was thinking of using plastic plenum to protect the cable run from the roof to the ground floor. You typically see this where Fiber Optic cables are used and It is sold at the HD..



Quick note
I never would have made it this far without the help of this Forum.

Regards
Brian
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: PV Cable Alternatives

    For those who don't do metric, 20 metres is about 65 feet.
    That's quite a long run.
    The missing bits of the equation: how are the panels wired and what Voltage are they?
    All in parallel and you have lower Voltage @ higher current: not good. But if you have an MPPT controller and can run them in series you get higher Voltage @ lower current, which will work better.

    You probably won't be able to use speaker wire, though. Unless it's around 12 AWG.

    Whatever wire you use needs to be either rated for UV exposure or (preferably) protected inside conduit. Keep in mind that local building codes/inspections may apply, in which case you'll have to comply with whatever the AHJ says.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,457 admin
    #3
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    Re: PV Cable Alternatives

    Don't use anything like Monster Speaker Cable... It is not designed or rated to any NEC standards (sun, oil, moisture, temperature, conduit use, aging, etc.).

    If you get the Monster cable for free, can install it in some sort of conduit (protect from sun/weather), and don't have any hazards (no brush, wood structure, kids in area, building inspectors, over size current capacity, etc.)...

    I am not trying to be a pain here... More than likely you are smart enough to figure out how you can use 12 awg speaker wire to be "relatively safe"...

    The real answer is nobody here can give you the "correct way" to use speaker wire (unless is it UL marked/rated for your application). There are too many unknowns.

    Using plastic plenum jacket to carry power from the roof--I am not sure that would ever be legal. Plenum rated cable just burns with a less smoky flame (and is "fairly" fire resistant--as far as plastic jackets are concerned).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #4
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    Re: PV Cable Alternatives

    I think even considering using "speaker" cable of any size is not good. I would consider some double insulated power cables would be ok ..just.. like builders cable .. but really unless you can run the cable totally onside a conduit I think you should be using the correct size cable like the cable that came with the panel/s.:cool:
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #5
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    Re: PV Cable Alternatives

    Pardon the diversion, but I would not spend a dime on Monster Cable for *any* application. In the first place they make all sorts of outlandish and unprovable (i.e. snake oil) claims about the audio characteristics of their wire and cable. In the second place, their business practice of filing nuisance lawsuits against anyone who uses the word "monster" in any sort of commercial venture irrespective of context is, IMO, deplorable.

    Back to your regularly scheduled programming...
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  • raydias
    raydias Solar Expert Posts: 68 ✭✭✭✭
    #6
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    Re: PV Cable Alternatives

    I buy my MC4 cables from aurora power and design. very reasonable prices for the lengths.

    I would use cable designed for the job at hand regardless of the supplier. From a novice perspective I have used other cables that in the end had to be replaced either due to my upgrading to more panels or my mind catching up with the voltage loss calculations. Keep it simple and you'll save money and hastles later
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  • SirSparks
    SirSparks Solar Expert Posts: 43 ✭
    #7
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    Re: PV Cable Alternatives

    I am using marine grade 2 conductor Round #10's with outer sheathing rated for sun,oil, 105C etc. One Home run for every 5 amps max.(every two panels with 24V). Max length 15ft average length 10ft.

    I am using soldered MC4 connectors and heat shrink tube to seal the open ends of the outer sheathing. The least expensive, neatest and best way I could find.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,457 admin
    #8
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    Re: PV Cable Alternatives

    There has been lots of discussions here about the differences between swagging electrical connectors and soldering (or swag+solder) connectors.

    Personally, I believe a good crimp is much better than solder for multiple reasons... But in any case, if you solder your connections, make sure they are well supported against movement/vibration/falling wiring if a solder joint fails. Do not force the soldered connections to carry mechanical loads by themselves.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • bmet
    bmet Solar Expert Posts: 630 ✭✭
    #9
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    Re: PV Cable Alternatives

    In the Air Force, I was taught never to rely on soldier to make my electrical connection. The physical connection is made by the wire-the solder's purpose was to 'remove' the corrosive influence around the connection.
    BB. wrote: »
    There has been lots of discussions here about the differences between swagging electrical connectors and soldering (or swag+solder) connectors.

    Personally, I believe a good crimp is much better than solder for multiple reasons... But in any case, if you solder your connections, make sure they are well supported against movement/vibration/falling wiring if a solder joint fails. Do not force the soldered connections to carry mechanical loads by themselves.

    -Bill
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #10
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    Re: PV Cable Alternatives

    You know we've had this discussion before on here about soldered vs. mechanical connections.
    john_p tested it and, no surprise to us older folk, found that the old method we were taught sixty-five million years ago is best: solid mechanical connection and solder to make a solid electrical connection.

    Both is best.
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  • SirSparks
    SirSparks Solar Expert Posts: 43 ✭
    #11
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    Re: PV Cable Alternatives

    Did you guys rent a battery lug crimper? They cost a fortune to buy.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #12
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    Re: PV Cable Alternatives

    did you see this from our host?
    http://www.solar-electric.com/hacrtoforlal.html
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  • machineman
    machineman Solar Expert Posts: 129 ✭✭✭
    #13
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    Re: PV Cable Alternatives

    I'm using >80ft run of #8-3 multistrand submersable pump cable. Buy it by the foot, ~$1.60/ ft.

    Off Grid Cabin, 24V 440ah 6V GC battery bank, Xantrex MPPT60-150 CC, Magnum MS4024 inverter-charger, >1200w Solar bank

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  • SirSparks
    SirSparks Solar Expert Posts: 43 ✭
    #14
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    Re: PV Cable Alternatives
    SirSparks wrote: »
    Did you guys rent a battery lug crimper? They cost a fortune to buy.

    WOW ! spent twice that on solder filling up those big voids.
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  • jacknife
    jacknife Registered Users Posts: 6 ✭
    #15
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    Re: PV Cable Alternatives
    raydias wrote: »
    I buy my MC4 cables from aurora power and design. very reasonable prices for the lengths.

    I would use cable designed for the job at hand regardless of the supplier. From a novice perspective I have used other cables that in the end had to be replaced either due to my upgrading to more panels or my mind catching up with the voltage loss calculations. Keep it simple and you'll save money and hastles later

    Tell me about your inverters, what are you getting out of them.
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  • SirSparks
    SirSparks Solar Expert Posts: 43 ✭
    #16
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    Re: PV Cable Alternatives
    jacknife wrote: »
    Tell me about your inverters, what are you getting out of them.

    I get about 115 volts out of mine.
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