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Re: [RFI] DirecTV to ground or not to ground

To: "rfi@contesting.com" <rfi@contesting.com>
Subject: Re: [RFI] DirecTV to ground or not to ground
From: "Jim Brown" <jim@audiosystemsgroup.com>
Date: Wed, 24 Dec 2008 21:10:56 -0800
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
On Wed, 24 Dec 2008 21:04:26 -0600, jvpoll@dallas.net wrote:

>b) History, practice and more importantly, mistakes in 
>practice (accidents) have made important contributions 
>to the NEC than simple theory would or  could predict;
>take for iinstance grounding practices. What _is_ the 
>rationale for grounding the secondary circuit (the 
>service to the home) of a power transformer for instance? 

>This isn't strictly neccessary for that service to 
>function. (I am asking this for the purposes of bringing 
>forth an example; I can cite cases where, in practice, this 
>has saved property and/or life, but that is different than 
>a statement or the treatment a textbook might give.)

>Could you cite a textbook wherein that rationale is brought 
>to light? 

One reference is the tutorial cited below. While it's written 
for sound and video contractors, the fundamentals apply to 


It all comes down to safety. The secondary is bonded to provide 
both lightning safety and, with the equipment (safety) ground 
conductor (green wire) provide a solid path to blow a fuse or 
breaker if a fault develops that could shock someone or start a 
fire. The lightning protection comes from because the bond to 
earth limits the potential that can exist in the event of a 
strike. The concept behind lightning protection is to have the 
whole building rise in potential by the same amount.

NEC can be purchased in annotated form -- that is, with 
explanations and commentaries interspersed with each paragraph.  


Jim Brown K9YC

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