BP 970 B grounding (or not)

Go figure, I have one of the first jobs under my personal company name, and I have some freak of nature panels that don't exist. They are 70 watt engineering samples that some guy got a good deal on. The problem is they are only two sheets of glass glued onto the cell structure. There is nothing to ground to, no grounding terminals of any type., and no metal I will call BP and the inspector in the morning but as I have learned the panels need to be grounded, and you can't attach to glass. Grounding the rack does not count to the NEC. Any input would be greatly appreciated.


  • BB.BB. Super Moderators, Administrators Posts: 32,599 admin
    Re: BP 970 B grounding (or not)

    If this is grid tied--then you (most likely) don't want to ground either of the array leads either... (depends on the inverter).

    I guess the first question is how are you going to mount the panels? The normal panels have the metal supports to ensure that they don't move/break under load/sun/storms/lighting. Who is building the mounts and will they guarantee that the panels will last and not crack/short/blowout? In my town, I had to have a structural engineer (or engineering report) on the panels and mounts that they would withstand (IIRC) ~125 lbs per sq.ft. of static load. Will these "homemade" attachments meet the requirement and have a structure engineer's signoff?

    Second, are the panels UL Listed? UL lists the panels (from what little I know) as 600 Volt Isolation (same as standard house wiring).... If not UL Listed, how do you determine/guarantee that the panels do actually have 600 volt isolation.

    Third, the only grounding I can think of is that the frames that hold the panels will need to be grounded--would give you the same thing as panels with frames--but you might have a problem convincing the inspector...

    My bet, the 70 watt engineering samples are not UL/NRTL tested/listed, have no NRTL tag/traceability, and would not allowed (under NEC/Uniform Building Code) to be connected to a Grid Tied system under NEC. And the inspector--if he/she is paying attention would red-tag the job.

    The above are just my guesses--I don't have an NEC book or building code for your area--so I can only offer suggestions of issues.

    If this is a DC battery system (12-48VDC Bus), you may be able to ground the DC leg of the panel and wave your hands for approvals (even if it has a grid tie interface).

    Also, grounding of the panels/DC legs should be addressed by the Inverter's (or solar controller's) installation manual. If you can make the grounding of the manual (hopefully NRTL approved inverter/controller) match that of your system, the inspector will probably OK it.

    Much of this will now be your responsibility--Personally, if the panels have no UL/CSA/NRTL certs--I would tell the owner that they cannot be used for a Grid Tied solar installation (in the US). Tell him he supplied the wrong components and they are not certified for this installation.

    I know that this is very difficult for you--ticking off a new customer for a young business is not a great idea. If you can tell him that the panels would not be allowed by the inspector/NEC/Building-Code (and would violate your electrician's license for you to install--if it does), you might be able to convince them that you are just looking out for their safety and their home. Perhaps, the panels can be returned to whomever supplied them--or be used in some off-grid application (either by the customer or perhaps you know someone that can take them).

    Good Luck,
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: BP 970 B grounding (or not)

    The placard on the back of the panels indicate they are UL approved. The panels are mounted by sandwiching the edge of the modules with a rubber protective strip and some galvinized deal that bolts to pro solar's aluminum strut. The pre-packaged system came with a xantrex gt 3.0 Xantrex had little to say about it when I called, BP solar tech's are a bit difficult to get ahold of. The system came with a line drawing indicating the array is grounded. I am guessing they sold the panels cheaper due to the fact they can't legally install them. I have some PDF's I could email if you get really interested, had I an email address to send to. Great looking panels, I hope I can make this fly.
    [email protected]
  • BB.BB. Super Moderators, Administrators Posts: 32,599 admin
    Re: BP 970 B grounding (or not)

    I have no problem giving you my email--however, I probably cannot help you much more that I gave above... I no longer have UL contacts or the books. If the panels are UL approved without the metal frames (you should be able to look up in one of the UL books--perhaps on-line now--to verify that they are UL approved without the frames), then grounding the roof mounts is about all you can do.

    You might check the panel "clamps" and see if they are either UL Listed/Reg. and/or include an obvious grounding point. If there is a an earth ground symbol on the clamps--you are probably good to go.

    From what little I have read about Xantrex, technically, they appear to ground one leg of the array input (typically the negative side unless the positive ground option was ordered) through a 1 amp fuse (used to detect ground faults if fuse blows--I guess). I would sure try and wave my hands with the inspector to indicate that the array is grounded through two different means--one the panel clamp and/or roof frame, and secondly, through the inverter with a ground fault detection circuit/fuse.

    From understanding how UL/NRTL's and building codes work, as a design engineer, we are trying to create a reasonably safe environment for service folks and users. Grounding through the Xantex and grounding the frame/clamps, would seem to meet those requirements.

    My guess is that if this is mounted on a roof, that the building inspector is not really going to climb up there and expect you to drill a glass panel to attach a green wire. You can show him the factory installation guide, point to the green/yellow strip wire connections (using properly rated wire and connections) on the roof clamps/frame, and that will probably be good enough.

    I am of two minds about trying to "pre-approve" the installation with the inspector. It would be nice to get them all warm and fuzzy that you and they have reviewed all of the issues, vs, just you convincing yourself that you have met all of the codes (using rated components properly and safely installed) and just let them pay most of their attention to the Xantrex/Shut-off switch/breaker panel/ground rod-water pipe connections.

    PG&E did no inspections at all, last September, on my residential installation--he just looked for the city inspection sticker and changed the meter (E-7 TOU for me)--and PG&E promptly messed up my next power bill by charging me $400 (instead of a $20 credit--wife almost had a heart attack when opening the bill) because they left the old E-1 meter plugged in while my solar power system turned the meter backwards (they just added 1,000 kWhr assuming that they read the meter wrong). From other folks I have heard that the first solar bill is almost always messed up in some way.

    In the end, given that the panels are marked with UL--you should be OK there. If you can show that the UL has been approved with the clamp system you will be using--that is about all anyone can ask for. I cannot think of any reason why you would have any major issues with the inspector and/or NEC/Building Code.

    Good Luck,
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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