Auxiliary grounding electrode for an array

[Dsg319]

I know nothing of PV systems. But was wondering if you do decide to have an auxiliary grounding electrode.

Do you have to have a bonding jumper to terminate in the intersystem bonding connection device like cable/comms/satillite does Or does it being connected the the EGC suffice for bonding the electrode conductor back to it?

 

[jaggedben]

First of all there's only one circumstance I would install an auxiliary grounding electrode for a rooftop array: if the AHJ forced me to. Mike Holt has done a half-hour video one why it is a useless and possibly dangerous idea. You didn't say what code you're trying to follow but auxiliary electrodes have been removed from the 2017 and 2020 NEC. I think they are a fundamental misunderstanding of what grounding is and does.

(For a ground mount, there might be some lighting protection utility to a ground ring that surrounds the whole installation; I'm not enough of an expert to say. I do think I'm enough of an expert to say that a ground rod for a ground mount won't do a thing, especially if the ground mount is supported by numerous metal piers that effectively meet the requirements for building steel to be an electrode.)

(Another thing that might muddy the water is if the array is on a detached building that has no other power. If that's your situation let us know.)

So as far as your question...
It's kind of unclear what you're asking, but the answer is pretty clearly no.
For an auxiliary array electrode, you install a Grounding Electrode Conductor between the equipment (solar array) and the electrode in the ground. That's it.

Note that you still need an EGC from the array back to your ground bar at your inverter or micro-inverter breaker or wherever the power circuits are going from the array. That's very important. (In fact it's infinitely more important than an auxiliary electrode, because an auxiliary electrode isn't important at all. )

Intersystem bonding devices are basically for non-power-supply conductors like the ones you mentioned.

 

[Dsg319]

First of all there's only one circumstance I would install an auxiliary grounding electrode for a rooftop array: if the AHJ forced me to. Mike Holt has done a half-hour video one why it is a useless and possibly dangerous idea. You didn't say what code you're trying to follow but auxiliary electrodes have been removed from the 2017 and 2020 NEC. I think they are a fundamental misunderstanding of what grounding is and does.

(For a ground mount, there might be some lighting protection utility to a ground ring that surrounds the whole installation; I'm not enough of an expert to say. I do think I'm enough of an expert to say that a ground rod for a ground mount won't do a thing, especially if the ground mount is supported by numerous metal piers that effectively meet the requirements for building steel to be an electrode.)

(Another thing that might muddy the water is if the array is on a detached building that has no other power. If that's your situation let us know.)

So as far as your question...
It's kind of unclear what you're asking, but the answer is pretty clearly no.
For an auxiliary array electrode, you install a Grounding Electrode Conductor between the equipment (solar array) and the electrode in the ground. That's it.

Note that you still need an EGC from the array back to your ground bar at your inverter or micro-inverter breaker or wherever the power circuits are going from the array. That's very important. (In fact it's infinitely more important than an auxiliary electrode, because an auxiliary electrode isn't important at all. )

Intersystem bonding devices are basically for non-power-supply conductors like the ones you mentioned.

Thank you, as I don’t have time to comment back in full detail at the moment I 100% additional “auxiliary” electrodes are waste of time and money.

I was just doing some reading and seen where they are allowed but not permitted and was just wondering if they needed to be bonded back to the service equipment GES.

I know that multiple grounding electrodes in a system not bonded together can cause voltage gradients from induced voltages from lightning strikes.

 

[jaggedben]

Your auxiliary electrode will be bonded to your array. Your array, via its regular EGC, will also be bonded to the premises GES back at the service. Thus the two electrodes will be bonded together. The fact that this happens over the roof and possibly through equipment is what makes this an inadvisable practice. Yes, arguably it could be better to bond the two electrodes at ground level, although the path over the roof is still there and would still conduct the dissipation of a lighting strike.