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Re: [TowerTalk] Urgent: Should solar panel array be grounded to station

Subject: Re: [TowerTalk] Urgent: Should solar panel array be grounded to station ground and/or house ground?
From: Grant Saviers <>
Date: Tue, 09 Oct 2012 08:26:57 -0700
List-post: <">>
I had 7 2.5kw arrays (17.5kw) each one on an 8" sch 40 pipe buried 12' in 6 yards of concrete per county wind and seismic foundation requirements (don't ask - they are idiots). So all array frames were grounded quite well. It would seem to me that your roof mounted frames should ground direct route to multiple ground rods and not to the entrance panel ground. I'm assuming your system is series connected panels for a few 100v DC and the DC lines are floating to ground.

My system was MPP managed at the inverters. If you have MPP controls or monitoring per panel, then the control signal wiring from panels to house raise a more complex set of issues.

Grant KZ1W

On 10/9/2012 6:13 AM, John W wrote:
Installers are here and in the process of installing a PV solar panel system on 
my house for electricity generation.
My question is about how they should ground the roof rails.
Their plan is to: (1.) Run the ground wire from the roof rail system directly to the ground bus in the house's main circuit breaker panel, and NOT install any separate ground rods to ground the roof rails directly to the earth. Is that acceptable for lightning protection? (The concern is lightning, not code conformance, because the town inspector will be here this afternoon to insure code conformance.) This design seems less than ideal because the existing ground wire from the house circuit breaker panel makes several small-radius turns between the panel box and the ground rod. Plus it brings lightning energy from the roof into the house and right into the circuit breaker panel box if the roof gets hit. There are two other things that I can think of that could possibly be done, either alone or in addition to (1.) above: (2.) Run the roof ground wire down to one or two ground rods driven at a point that allows for the shortest, straightest possible ground wire.
(3.) Run the roof ground wire down to the existing main house ground rod that is 
bonded to the panel. (As a practical matter, they would strip part of the existing 
ground wire insulation and connect to that wire with a split bolt at a point about 
18" above the ground. My preference would have been a cad weld, but I don't 
think that will be possible because they aren't equipped for that.)
I plan to eventually run a full perimeter ground around the house and bond it to my 3 or 4 towers. But I have not run it yet, because I haven't installed my towers yet.
I am planning to tie the perimeter ground to the existing house ground rod, 
hopefully by cad welding, as well as to my station ground.
My question: Is (1.) above sufficient? Should they also do (2.) and/or (3.) and/or something else? Another option would be to let them just do (1.) now, and then later when I install the perimeter ground, I could run another ground wire from the roof rails to the perimeter ground. Curious if you have any thoughts on grounding option 1 vs. 2 vs. 3 vs. a combination of them. How have other hams who have solar arrays grounded the array? Hoping for very quick answer to this question, because they guys are here now and they need a decision today so they know where to run the wires.
(If you are reading this after 5 PM EDT on Oct 9, then you don't need to spend 
any time replying, because it will be too late to change the design.)
Thanks in advance to all you lightning and grounding experts, John

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