The system in question does not have a transformer so a grounding rod is not required as it is not a separately derived system.
The equipment grounds should be tied together to prevent any difference in potential though.
The system in question does not have a transformer so a grounding rod is not required as it is not a separately derived system.
The equipment grounds should be tied together to prevent any difference in potential though.
I’m an electrical engineer. I just want to explain the hazard with panels.
They are DC, and the voltage is usually very high, between 300V and 600V.
At this voltage you will get a burn, like touching a hot kettle, but because it is DC you will be able to easily “untouch” it.
Yes, the panel frames should all be grounded to each other, and also to Earth in one spot along the chain, as this makes it more difficult to be electrocuted by them because the resistance of the grounding wire is much lower than the resistance of your body, and electricity takes the shortest path.
I was just pointing out that a solar installation with only an inverter and no transformer does not need a separate ground since it’s not a separately derived system. An auxiliary/supplementary ground rod is allowed by the NEC (250.54) but it is not required.
There are many different ways to connect solar panels to the inverter. Usually the exposed metallic parts will be “grounded” (bonded to the ground / protective earth / equipment grounding conductor / whatever your jurisdiction calls it at the inverter).
But this is an array that looks a bit remote from any structure, and even if the electronics themselves are utterly, perfectly safe, the bonding wire will cause the panel frames to be at the potential of the inverter’s ground, and the soil will be at whatever its local potential is, and this may be different, resulting in a “touch potential”. You can mitigate this with a supplemental ground (or whatever your jurisdiction calls it) closer to the panels. There are fancy ways to do this particularly well to improve safety in the event of a fault.
If you are contacting the actual power wiring of the solar array, something is wrong. If you are feeling capacitive coupled current from the power wiring of the array, then I imagine this means your inverter has crappy filtering, and again the only way you would feel it is if the panel frame isn’t at the same potential as the local soil.
Oh, and if you live somewhere prone to lightning, you probably want to give a possible lightning strike to the panel a better route to a high quality ground than through the bonding wire to your house.
(In fact, in many parts of the world, including IIRC 48 US states, the power utilities may operate their distribution networks with a current carrying wire (combined neutral and ground) that is grounded at multiple points along its route, which will generate substantial leakage current through the ground. The exceptions are IIRC California and Wisconsin, and IIRC those states have their rules to help protect cattle from becoming part of an undesirable circuit while being milked. In CA at least, all the distribution transformers on the poles have at least two bushings on the primary side, and this is why. I believe this is California General Order 95, rule 33 [0].)
[0] https://ia.cpuc.ca.gov/gos/go95/go_95_rule_33.html
> Usually the exposed metallic parts will be “grounded” (bonded to the ground / protective earth / equipment grounding conductor / whatever your jurisdiction calls it at the inverter).
It’s not usually, all of the panels and also the metal racking must be bonded and grounded.
Supplementary grounds are allowed by the NEC, article 250.54
There are zero requirements for supplemental grounds, you could use a single 24AWG conductor bonded to a brad nail or a #6 bare copper conductor bonded to (3) 5/8” dia’ 10’ ground rods. The fact that there are no requirements should tell you something about the necessity of supplemental grounds.
> 250.54 Auxiliary Grounding Electrodes. One or more grounding electrodes shall be permitted to be connected to the equipment grounding conductors specified in 250.118 and shall not be required to comply with the electrode bonding requirements of 250.50 or 250.53(C) or the resistance requirements of 250.53(A)(2) Exception, but the earth shall not be used as an effective ground-fault current path as specified in 250.4(A)(5) and 250.4(B)(4).