Module grounding revisited [RE-wrenches]

[Joel Davidson]

Bill,
Thanks for pointing out that PV module manufacturers are responsible for solar
module design which includes grounding. One manufacturer states, "We recommend
you attach all module frames to an earth ground. Attach a separate ground wire
to one of the extra mounting holes on the module frame with a self-taping screw.
The racks must also be grounded unless they are mechanically connected by nuts
and bolts to the grounded modules. Grounding is achieved by securing the array
frame for both roof and field mounted applications. Additionally, the array
frame shall be installed in accordance with NEC Art 250." Which manufacturer
offers the most installer-friendly grounding?
Joel Davidson

Joel Davidson

Bill Brooks wrote:

> William,
>
> I apologize for not having a chance to answer your original question, but it
> "sparked" a good discussion and I think that John Wiles summed up the
> technical issue quite nicely.
>
> One thing no one has mentioned is the fact that this issue is PRIMARILY the
> fault of the module manufacturers. They know that a huge percentage of their
> modules, and almost all of their 72-cell modules are going on rooftops and
> yet they still have not adequately addressed how to readily ground each
> module.
>
> There is no doubt that the existing locations (back of module) is the last
> place I would want to ground the module when putting it into a standoff
> mounting system. Manufacturers are simply too lazy to figure out a better
> way and the installer is stuck with extra work to ground it properly. Should
> a racking system be acceptable for grounding---ABSOLUTELY--as long as it is
> tested and approved to provide adequate grounding of the modules. Continuity
> or resistance tests are irrelevant when it comes to frame grounding. The
> grounding system must be able to carry full fault current for as long as
> necessary to trip the overcurrent device. Many frames will have a very high
> resistance to ground as soon as you try to pass any current through a racked
> connection.
>
> So talk with your module manufacturers and tell them what a pain they are
> causing good installers in the field. They will only listen if numerous
> people raise this issue. If it is too difficult to ground properly,
> installers won't do it and now we have higher voltage systems proliferating
> with inadequate grounding. Hope this adds to the discussion--and I hope some
> module manufacturers are listening--are they allowed on this list???
>
> Bill.
>
> -----Original Message-----
> From: Jay Peltz, Peltz Power [mailto:jay at asis.com]
> Sent: Thursday, October 31, 2002 8:11 AM
> To: RE-wrenches at topica.com
> Subject: Re: Module grounding revisited [RE-wrenches]
>
> Hi William,
>
> In my experience, most inspectors agree that its just equipment
> grounding.  All
> parts are metal, and connected, so one "ground" per rack is just fine.
> ***snip****
> p.s. inspectors accept all kinds of non-compliant installation practices.
>
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