[RFI] Station ground - more

[Christopher Brown]

NOT an AHJ or electrical worker, so do you own research...


They are confusing allowed secondary grounds with what _must_ be done
for the primary wiring.

They used to allow a separately derived "ground" with a ground/neutral
bond at the remote building.  This is no longer allowed for most
outbuildings...The grounding conductor must run with the power feed and
the only neutral/ground bond has to be back at the main feed.


That being said, nothing in the NEC bans "extra" ground rods.


You can tie "extra" rods that _are not_ bonded back to the GES to the
grounding conductor or your gear, is allowed it just does not remove the
requirement for a normal grounding conductor.

You can also add "extra" rods and bond them back to the GES with #4 or
better.

Under newer versions, one is "supplemental" and the other is
"supplementary" (can never keep them straight).


So, 3 rods at the outbuilding connected to the outbuilding panel ground
bus is fine, BUT you must still run a grounding conductor along with the
power and you _must not_  bond Neutral and GND at the sub-panel.


You can BOND all of your station gear together (very good idea), and you
can BOND the assembly to a "extra" set of rods that are or are not
bonded back to the GES with #4 or better.


My station is like this.

My station is _all_ DC.

All gear is bonded to heavy copper bonding bus that is bonded via wide
flashing/strap to multiple rods and flashing electrodes.  These rods/etc
are bonded back to the GES (grounding electrode system) with #4 solid.

The DC supply/battery charger is isolated output type, so the charger
itself including chassis is connected to the AC ground with the incoming
power...The DC common output (DC -) (isolated from input) is bonded to
the station bonding bus.  This complies with NEC (local bonding
bus/electrodes bonded back to GES with #4) and keeps alot of RF hash on
the AC ground wire off of the station, but is only possible because of
an ALL DC shack with an isolation type charger.

If I was running mixed AC/DC shack, the AC grounding conductor would
have to bind to the local bonding bus even if only via the gear itself.


This is similar to the antenna grounding examples where a remote coax
run may be bonded to a local rod which is in turn _properly_ bonded back
to the GES.





On 9/28/16 08:37, Kenneth G. Gordon wrote:
> For instance, when I was wiring our new addition, the wiring included a sub-panel, 
> connected to the main panel by a run of #00 4 wire cable. With the assistance of our 
> youngest son, we drove an 8' ground rod directly under the sub-panel with the thought that I 
> had to connect that to the sub-panel's ground lug.
> 
> Yet I was told by the electrical inspector that this was NOT allowed, but that we had to run a 
> separate ground wire from the sub-panel at least 30 feet to the main-panel's ground lug and 
> connect them together there.
> 
> I was also told that the ground-rods we drove (3 ea 8 footers, separated by at least 6 feet 
> and all tied together) must be the ONLY such ground system in the entire home, and that 
> every grounded item in the entire home must be connected to that and only to that.
> 
> So, why the apparent discrepancy?
> 
> For one thing, I suspect that the ~30' long ground wire from the sub-panel to the main panel 
> is conducting RF, especially on 40 meters, into some of the electrical appliances in the new 
> addition. I also believe that the present ground system in the shack is not adequate, since at 
> present it is only being connected to the panel-ground through the green grounding wires of 
> the electrical service.
> 
> Ken W7EKB
> 
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