Question regarding PV grounding to combiner in attic

Discussion about the Power System PV Combiner (PSPV)

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Question regarding PV grounding to combiner in attic

Post by MJSullivan56 »

I plan on having two strings of six panels each on the roof of my house. Both strings will share the same racking. I plan on running two nylon JBOXes through the sloped roof, one for each string. The strings will be combined together downstream using a combiner in the attic. This combiner will naturally be grounded back to the Outback inverter.

My question is straightforward: given that the rack will have a shared ground, do I run a single grounding wire through just one of the JBOXes, or do I run dual grounding wires (one grounding wire per JBOX)?

My concern: Won't running two grounds present a possible "ground loop"?
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Re: Question regarding PV grounding to combiner in attic

Post by raysun »

If the racks and panel frames are all connected, a single ground wire will keep them at the same ground potential.
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Re: Question regarding PV grounding to combiner in attic

Post by fcwlp »

I would also recommend you look at the NEC. All DC PV wires need to be in EMT conduit and most likely in metal junction boxes. Logic is that if it an arc starts at that location the metal JB will contain it. Recommend you look at Soladeck for the roof penetration and also can be used for junction box.
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