[TowerTalk] Urgent: Should solar panel array be grounded to station ground and/or house ground?

[Jim Lux]

On 10/9/12 8:34 AM, John W wrote:
>
> Hi Chas,
>
> The current plan is this:
>
> They are going to run a #8 ground stranded wire down from the rail
> system, following the same route as the electric wires, attaching it
> to the ground bar inside the load center subpanel up in the attic,
> then continuing from there down through the conduit to the ground bar
> inside the outside safety disconnect box, which will be installed a
> few feet above ground, and then continuing from there and attaching
> to the ground bar of the main house panel where the electrical
> connections are also being made.  Then relying on the ground from the
> main house panel out to a ground rod or two.  (Not sure what the
> builder has installed, it was 1998 and I wasn't here, but I'm going
> to email him and see if he remembers.)

House built in 1998... You probably have a concrete encased grounding 
electrode (aka Ufer ground).  It depends on where you are, and I can't 
remember when the code changed, but these days, you can't use a rod as 
your sole grounding means.  And, a Ufer ground is so easy and works so 
well, there's no good reason not to do it.  They just lay 20 feet of 
wire in the slab when pouring it, or stub up a piece of the rebar above 
the slab surface.


>
> In addition to the above, for lightning protection, I am also having
> them run a #6 stranded ground wire from the roof rail system straight
> down the side of the house to a 5/8" 8' ground rod which I am about
> to go and drive into the ground. That rod will eventually get tied to
> my perimeter ground as well, once I install it and the towers.

That rod needs to be tied to the "house ground" with a uninterrupted 
AWG6 or larger conductor to meet code.