Need help/advice on MC cables

System
System Posts: 2,511 admin
in Solar Beginners Corner #1
I purchased an 80w solar panel for a project I am doing. The panel came with just a junction box on the back, and no MC cable pigtails. Strangely, the place I bought the panel from said that they did not sell the cables and could not even tell me where to buy them.

I purchased one MC cable and it does not fit the odd connectors on the junction box. I opened the junction box to see what it looked like on the inside, and after seeing that and comparing to various MC cable types, I do not see ANY cable connector that will work with this.

I have attached pictures of the junction box connectors, as well as the inside...can someone identify what type of cable connector will work with this? As a last resort I could always just cut the connectors off the cable I already purchased and solder them directly to the terminals, but I'd prefer to "do it right".

Any advice is appreciated, thanks!
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  • McClary's Electrical
    McClary's Electrical Registered Users Posts: 21 ✭
    #2
    Re: Need help/advice on MC cables
    Blazer wrote: »
    I purchased an 80w solar panel for a project I am doing. The panel came with just a junction box on the back, and no MC cable pigtails. Strangely, the place I bought the panel from said that they did not sell the cables and could not even tell me where to buy them.

    I purchased one MC cable and it does not fit the odd connectors on the junction box. I opened the junction box to see what it looked like on the inside, and after seeing that and comparing to various MC cable types, I do not see ANY cable connector that will work with this.

    I have attached pictures of the junction box connectors, as well as the inside...can someone identify what type of cable connector will work with this? As a last resort I could always just cut the connectors off the cable I already purchased and solder them directly to the terminals, but I'd prefer to "do it right".

    Any advice is appreciated, thanks!



    That is a compression rubber cord connector, not an MC connector. You need the correct diameter rubber cord to fit that connector, or vice versa. Get your self some SO cord
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  • System2
    System2 Posts: 6,290 admin
    #3
    Re: Need help/advice on MC cables

    Can you be more specific? I googled around for compression cords, so cords, and found nothing.

    The place I ordered the panel from told me I would need a male and female MC connector, even after I told them that the panel had very NOT mc-like connectors...you'd think they would know their own product, obviously they do not!

    Thanks!
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  • drees
    drees Solar Expert Posts: 482 ✭✭✭
    #4
    Re: Need help/advice on MC cables

    Your supplier is right.

    You need a male and female MC connector (appropriate for whatever you want to plug the panel in to), or if you simply just want bare leads coming out, you just feed one wire in each compression fitting into the junction box, crimp a tab connector to the wire and bolt it down. Then put whatever connector you want on the other end.
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  • System2
    System2 Posts: 6,290 admin
    #5
    Re: Need help/advice on MC cables

    Okay so basically it needs to be hard wired (at least on the panel side), and there is no connector that will just plug in to those ports somehow. That's what I thought, but I have never seen a solar panel junction box so just wanted to be sure.

    Do you think I should just use "spade" connectors? It looks like they would clamp down well, as the terminal screws are holding down a small square of metal.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #6
    Re: Need help/advice on MC cables

    There is no connector!

    The is a Junction Box(J-Box) with water tight "strain reliefs" like these

    So run them through the strain relief, attach a lug, mount under the screws, tighten the strain reliefs.

    It actually looks like it has some type of lug in place that needs to be bent around the wire, but I would see if the screw will back out and if it's a lug replace it, if it doesn't back out I might use the bend over disign if I though there was plenty of room, but it looks tight.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #7
    Re: Need help/advice on MC cables
    Photowhit wrote: »
    There is no connector!

    The is a Junction Box(J-Box) with water tight "strain reliefs" like these

    So run them through the strain relief, attach a lug, mount under the screws, tighten the strain reliefs.

    It actually looks like it has some type of lug in place that needs to be bent around the wire, but I would see if the screw will back out and if it's a lug replace it, if it doesn't back out I might use the bend over disign if I though there was plenty of room, but it looks tight.


    Ditto. I can see the bare - uninsulated crimp lugs under the screw heads. Size your wire to fit the rubber bushing, and it's water proof. Adjust so water can't drip or run inside & you are fine.
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  • System2
    System2 Posts: 6,290 admin
    #8
    Re: Need help/advice on MC cables

    Okay we are on the same page now. :D Thanks guys!
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #9
    Re: Need help/advice on MC cables

    It looks to me as though the connectors are there already, for you to crimp over the # 10 or so wire that you want to use.

    EJ
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
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