[TowerTalk] Bonding entrance panel to utility ground question

Jim Lux jimlux at earthlink.net
Sat Mar 25 21:46:56 EST 2006

At 12:05 PM 3/25/2006, K3GM wrote:
>My coax entrance panel is now hooked to its own series of ground rods.  I 
>want to bond it and all of the Polyphaser arrestors attached to it to the 
>utility ground rod.

Such a connection is probably required by the electrical code in your area.

>  If the easiest and shortest path to the utility's entrance ground rod is 
> thru the interior basement of the home, can I, or should I use it?

As others have pointed out, running a conductor that might carry lightning 
under the house may not be the best plan.

>I have a large gauge stranded ground cable running from my well pump to 
>the service entrance ground rod and is very easy to hook to.

Here is where it gets tricky.  You'll have to look up the code sections to 
see if you can bond the antenna lightning protection ground to a electrical 
safety ground.  I'm going to guess that it's not a good idea.  a) you might 
cook your pump if lightning strikes; b) if your well pump has a short, and 
the grounding conductor winds up carrying significant fault current, then 
you might wind up making your station grounding panel "live".  However... 
check the code to be sure!

>  It runs across the the sill of the basement wall within several feet of 
> the entrance panel, into the garage where it eventually ties directly to 
> the ground rod. The alternative would be to run an outside wire around my 
> house, across a double wide driveway and then into my garage to get to 
> the utility ground.

Probably the best plan, overall.. Do you actually have to go "inside" to 
get to the ground?  Usually, there's a ground at your electrical service 
entrance.  It might be inside the wall, but the service entrance is usually 
on an exterior wall, so your ground bonding conductor can go through the 
wall right to the common ground point.

>   Would it be safe, (or code) to use this interior ground wire as part of 
> my lightning protection system?

A great reference on low voltage grounding (and antennas are considered low 
voltage systems) is the free downloadable handbook at http://www.mikeholt.com/

The code requires ALL external antennas to be grounded properly (dishes, TV 
antennas, etc.) and that handbook covers all the stuff you need to know 
(size of the wire, legal places to run it, all those things).

And, be aware that "code" isn't the same everywhere.  Each AHJ (authority 
having jurisdiction) typically adopts some revision of the code, and then 
makes some local modifications.  Often the code they use ISN'T the latest 
one. Most of the code doesn't change much over the years, but grounding is 
one of those areas where there's actually been a fair amount of fluctuation.

Jim, W6RMK 

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