[AT] grounds

[K7jdj at aol.com]

In a message dated 12/17/2007 5:43:10 P.M.  Pacific Standard Time, 
drupert at premier1.net writes:
In my initial post I  expressed my perplexity as to Warren's friends advise
that he didn't need a  ground rod at his shop ... and I am still perplexed.

Don't feel  alone.  The NEC has changed many times over the years and has 
attempted to  sort out some confusion on the subject of grounds.  If anyone is 
still  interested art. 250.56 addresses how many ground rods are required. 
Basically  you need two unless you measure the ground resistance (less than 25 ohms)
Not  many people have the equipment required to measure ground resistance and 
 therefore install two ground rods. 

On the issue of the installation of  secondary panels, generally if the panel 
is installed in the same structure it  must utilize the same ground that the 
panel that feeds it utilizes. (see art.  250.32 B and C)  If it is in a 
detached structure then it may (or not) use  a separate ground.  There are many 
arts. covering this issue and you will  find considerable professional different 
interpretations of these arts. There  are also exceptions and special 
considerations for structures that house animals  (barns).  I  find this a very 
interesting subject. 

In my past  life I inspected and tested electrical systems including  grounds 
and  neutral bounding for the Federal Aviation Administration at remote  
locations.  

I didn't mention the grounding of generators but the  code is reasonably 
clear on the requirements.  As the saying goes "it all  depends"  :)

Gary
Renton Wa. 
Who wishes I wasn't grounded  when checking plug wires on a running antique 
tractor.

2 F Cletrac's
1  W Cletrac
1 JD B
1 JD 350 crawler
1 JD 450 crawler
2 580 Case  backhoes
1 Ditch witch trencher
1 FMC chipper
and a lot of other stuff  




**************************************See AOL's top rated recipes 
(http://food.aol.com/top-rated-recipes?NCID=aoltop00030000000004)