[TowerTalk] Antenna/Tower Grounding (Lightning Protection)

[ersmar at comcast.net]

Frank:

     Thanks - that's the reference I had in mind.  What I correctly recalled was the requirement for six electrodes (ground rods) for self-supporting towers such as my own; I hosed up on the reference (ANSI/TIA-222) and on the number of wires to those six electrodes.  


73 de
Gene Smar  AD3F


 -------------- Original message ----------------------
From: <donovanf at starpower.net>
> Effective January 1, 1006; tower grounding standards in the United States are 
> specified in ANSI/TIA-222-G-2005.
> 
> Section 10.4 states:
> 
> Connections between a structure and grounding electroes or connection between 
> electrodes shall be compatible with the electrodes and be accomplished by leads 
> no smaller in surface area than 2/0 solid.
> 
> Gounding electrodes shall be as a minimum, be equivalent to 5/8 inch diameter, 
> 10 feet long metal rods constructed of copper, copper clad steel, galvanized 
> steel or stainless steel alloy. The minimum embedment depth of grounding 
> electrodes shall be 10 feet.  All electrodes must be connected to the structure, 
> however, all electrodes need not be interconnected
> 
> Section A.10.0 Protective Grounding states:
> It is intended that the owner or the owner's representative will verify that 
> total resistance will not exceed 10 ohms based on actual on site soil 
> conditions.  Additional grounding electrodes may be required.
> 
> For guyed masts the default grounding configuration shall be a minimum of three 
> grounding electrodes installed symetrically around the base of the structure at 
> a minimum 20 ft spacing and each symetrically connected to the base of the 
> structure.  A minimum of one grounding electrode shall be installed and 
> connected at each (guy) anchor.
> 
> For self supporting structures, the default grounding configuration shall be a 
> minimum of six grounding electrodes installed symetrically around the base of 
> the structure at a minimum of 20 feet spacing.  A mimumum of one lead shall be 
> connected to each leg for latticed structures and a minimum of thee leads shall 
> be symetrically connected to the base of pole structures.
> 
> 73!
> Frank
> W3LPL
> 
> 
> ---- Original message ----
> >Date: Thu, 4 Jan 2007 12:11:44 -0500
> >From: <ersmar at comcast.net>  
> >Subject: Re: [TowerTalk] Antenna/Tower Grounding (Lightning Protection)  
> >To: "Richard W. Solomon" <w1ksz at earthlink.net>, <towertalk at contesting.com>, 
> "Jim Lux" <jimlux at earthlink.net>
> >
> >Jim:
> >
> >----- Original Message ----- 
> >From: "Jim Lux" <jimlux at earthlink.net>
> >To: <ersmar at comcast.net>; "Richard W. Solomon" <w1ksz at earthlink.net>; 
> ><towertalk at contesting.com>
> >Sent: Thursday, January 04, 2007 10:10 AM
> >Subject: Re: [TowerTalk] Antenna/Tower Grounding (Lightning Protection)
> >
> >
> >
> >>>2.    Your tower ought to have at least one ground wire, minimum of #8 
> >>>gauge wire, to one ground rod within two feet of each tower leg.  The 
> >>>latest version of the National Electrical Code mandates two ground rods 
> >>>and two wires at each leg.
> >>
> >>
> >> Really?  Which code? The 2005 NEC is silent on towers, per se.  Art 810.15 
> >> says masts and metal structures shall be grounded in accordance with 
> >> 810.21.  810.21 just has the stuff about the size of the wire, straight 
> >> line runs, protection of the connections, and what can serve as a 
> >> grounding electrode.
> >>
> >> Art 820 (CATV etc) has very similar provisions.
> >>
> >>
> >> Maybe you're thinking of some lightning protection code? Or a 
> >> recommendation of a manufacturer?
> >>
> >>
> >> Jim, W6RMK
> >>
> >>
> >
> >     I'm pretty sure I read about these new grounding requirements in the 
> >latest (2008) proposed NEC here on TowerTalk within the past six months or 
> >so.  I can't just yet find that reference in the archives.  I'll do more 
> >searching and report back to the reflector.  But I'm just as certain what I 
> >read was not something from a manufacturer.
> >
> >73 de
> >Gene Smar  AD3F
> >
> >
> >
> > 
> >
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