Lay-in grounding lugs

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Is there any reason why we shouldn't use copper rated aluminum lay-in lugs on module frames? I know that tin plated copper is the de facto standard and unplated copper is right out, but my installers are asking me about the (much cheaper) aluminum ones that are copper rated. I have a nagging feeling that there is some point against using them, but I cannot remember what it is.

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,446 admin
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    Re: Lay-in grounding lugs

    Will they be "properly" rated this use per the NEC?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
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    Re: Lay-in grounding lugs

    Hi ggunn,

    I am Wiles-contaminated, but believe that the AL LI Lugs are not protected from corrosion. Are not/cannot be anodized, and all of the AL LI lugs that I've seen use a Zinc-plated set screw, which could be replaced, but believe that it time these will be nothing but trouble. The real-deal Tin-plated Cu with SS set screw ARE amazingly expensive. 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.
  • solarix
    solarix Solar Expert Posts: 713 ✭✭
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    Re: Lay-in grounding lugs

    From 1st hand experience, I can tell you that the aluminum lugs look horrible after a few years. The set screws corrode like crazy and the resistance to ground measures poor. Paygin for the good ones is a good investment. Paying for the 50 cent ones is a waste of money. We like the Tyco grounding lug that is Stainless Steel.