Panel warranty and attached connectors

inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
A recurring element in various threads is the question of what to do when the manufacturer-attached leads on a commercial panel have the wrong connectors on the end for whatever you are trying to do.

This usually leads into a mention that cutting off the supplied connectors will void the warranty. I would like to explore that a bit, and get input from others:

1. If the panel is UL-listed and you will be using it (now or in the future) in a system which is subject to inspection, removing the factory connector WILL void the listing. No question about that, since the connector is an important part of the safety of the panel.

2. If you are not concerned about that, the manufacturer is within his rights to refuse warranty service on any equipment which has been modified in any way. Using it in a different way than intended is much harder to establish and may not actually affect your warranty, but if what goes back for repair is not what went out, you could be SOL. Some manufacturers may be more liberal about this than others. Any experiences to report?

3. Finally, we come down to the area I am currently looking at: Assuming that you don't care about either 1 or 2, is there anything about cutting off the old connectors that could actually cause damage to the panels?
Some thoughts on this subject, and input from others is welcome:
  1. Moisture resistance: The MC4 connector probably is providing a weather-tight seal around the insulation of the wire. If you cut it off, would the remaining piece of wire allow moisture to enter the panel between the insulation and the core of the wire? It could if there is no seal at the other end of the insulated wire. But would it be significant?
  2. Corrosion: A non-weathertight connector could also lead to corrosion of the lead itself, but given that you have cut the original end off the lead anyway, you could repair the damage just by cutting back further and attaching a proper connector.
  3. Suitability for the voltage and current applied: This would affect the system, but would not cause damage to the panel itself, since you can short-circuit a panel without harm and arcing could damage the connector itself but not the panel.
  4. Chances of connecting the panel incorrectly: With MC4 connectors and no adapters in use, you cannot accidentally connect one panel backwards in a string, thereby exposing it to damage from reverse voltage in the amount of the Voc of the rest of the string. Definitely damage to the panel, but not super likely. You could still do the same thing using the original connectors plus adapters.
  5. Your turn....
SMA SB 3000, old BP panels.


  • petertearaipetertearai Solar Expert Posts: 471 ✭✭✭✭
    Re: Panel warranty and attached connectors

    I have cut off m3 connectors on my sharp panels then joined a 6mm cable to it to get to my combiner box. The join was sealed wit a tape called self amalgamating tape. This tape is fantastic stuff as the tape provides a moisture proof seal if correctly done.
    So im with you , cant see how it would damage the panel.
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
  • TnAndyTnAndy Solar Expert Posts: 249 ✭✭
    Re: Panel warranty and attached connectors

    I cut off my MC-3 connectors because the crappy things keep corroding (no....they are NOT water tight, apparently ), and I'd have pairs of panels dropping out. I have two arrays of 10 x 175w panels, (strings of 2 x 5 ) and an FX/MX-60 controller on each. The original 6 panels on each of these array was installed in 2007, and had MC-3 connectors....the remaining 4 were installed in a later expansion, and have the MC-4 connectors.

    Watching the display, I'd find one array running 250-300w less than the other some times......about one string. SO, I'd take out the clamp on DC ammeter, find the offending string, wiggle the connector some, and get it to producing again. It was always the MC-3 that was the problem.

    Finally got tired of that BS, and cut all of them off, along with the panel-to-panel (+) (-) MC-4 pair, reducing the wire length by about 7-8'.
    What I did was strip the wire, use a crimp on lug for #10 wire, then solder it as well, and use heat shrink tubing with the "goo" inside like I use on my water well connectors ( which SIT in water all the time on a submersible, yeah, they are waterproof ).

    Not only does that keep the arrays running very close to the same figure, but both arrays are running 30-40 watts over what they typically used to guess is the connections are that much better, and by cutting the panel to panel wire length down ( probably cut out 30-35' of wire ), the production is upped that much.

    Now, anybody want a pile of crappy connectors ?

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Panel warranty and attached connectors

    "Now, anybody want a pile of crappy connectors ?"

    gee, add a clock and a flux capacitor and you can go back to the future. now the real problem is getting the can up to speed.:p
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Panel warranty and attached connectors
    niel wrote: »
    "Now, anybody want a pile of crappy connectors ?"

    gee, add a clock and a flux capacitor and you can go back to the future. now the real problem is getting the can up to speed.:p

    Gotta be a few bucks worth of copper there anyway.
    SMA SB 3000, old BP panels.
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