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We are a sign company and our client wants his new illuminated (LED) ground sign to be powered by solar with battery storage. We have it all spec'd out but I want to make sure I'm following code but I can't find this answer. Does this 24vdc, off grid, system need to be earth grounded? It will have a 185 watt PV array and 2 batteries. If I don't have to I don't want to bury a ground rod 6 feet down. VERY difficult for us for this little project. Thanks.

Paul Jester
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  • Seems like your local authority is a better place to ask, but at least tell us where you are or what code you're attempting to comply with. – isherwood Apr 27 '18 at 18:21
  • For off-grid there is no real code in the US for this. Grounding is a good idea, however it is not a requirement. 24 Volt systems can often have PV panels wired in series that provide high voltage for the MPPT charge controller. Are you sure the system is insulated enough that nobody can come in contact with the higher-voltage side? – SDsolar Apr 27 '18 at 18:49
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    There's a little bit of Code for low voltage wiring, but I'm somewhat confused as to what the possible benefit would be. It might be useful if you were doing GFCI, as the ground path would provide an easy failure path. Its role in equipotential bonding is to keep neutral from floating 120V/230V (or 2400V in case of a transformer leak) above earth. Where would this other voltage be coming from that would float it so high? SDSolar's answer about "PV panels in series [giving 200++ volts] to feed a 24V controller" may be the answer. – Harper - Reinstate Monica Apr 27 '18 at 21:14
  • What's the maximum voltage on the PV side? Also, have you talked to your AHJ about alternative ground electrode designs? – ThreePhaseEel Apr 27 '18 at 22:59
  • afaik, if it's all low voltage DC then you don't need grounding. – dandavis Apr 28 '18 at 08:33

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