[R-390] Grounds

[rbethman]

Dave,

The "codes" vary.

Now that I've said that, do NOT start a flame war folks!

State, County, Local Municipal codes are different in MANY instances. 

Dave, I'm a fair bit East of you in Virginia.  The Cable TV folks, the 
Telephone folks, and ANY one else installing a feed to the house - ALL - 
attach "Their" grounds TO the Service entrance ground.

You are correct in the requirement that ALL grounds are bonded, (Now 
THIS is a loose term!), together.  This keeps the potential at the same 
level.

To be honest, my ground system is a WHOLE bunch better than what was 
installed here by the power company.  My Copperweld grounds are 3/4" in 
diameter.  Unlike that joke at the service entrance which I haven't 
measured, but looks to be around 1/4" to 3/8" diameter.

I ran my ground grid to the service entrance ground also.

Bob - N0DGN


Dave or Debbie Metz wrote:
> Following this thread, I have a further question.  It is my 
> understanding that all ground rods per the NEC need to be connected so 
> that a danger situation does not develop.  The specific example is the 
> ground rod (term used VERY loosely) that the cable company drives 
> outside your house at the entry point on one side of the house and your 
> ground rod at the opposite side of the house where the electric panel is 
> situated is not connected but that indiscretion is a major danger in 
> lightning protection.  As near as I can recall, the NEC requires ALL 
> ground rods to be connected to maintain no possible potential 
> difference. The danger as I understand is that the cable entrance has a 
> ground, your TV is grounded to the "other" ground via the house wiring. 
>   So,.... my question is: if we have additional grounds for our 
> equipment, are we safer or more in danger if we do not connect them to 
> the service entrance ground. Perhaps this is beyond the scope of this 
> reflector but it seems like we have some engineers lurking in the 
> background and I would really appreciate the science of this anomaly 
> when talking about grounds to the entire group.
>
> 73's
> Dave
> Kj4JX
>
>
>
> rbethman wrote:
>   
>> I'd suggest that you NOT have a lightning arrestor between the roof and 
>> the ground braid.
>>
>> The metal roof will, at the top of the second story, tend to be a 
>> lightning attractant.  Gounds for use to dissipate lightning strikes 
>> SHOULD have any necessary bends be a SMOOTH radius.
>>
>> Standard electrical ground rods are indeed at LEAST 8 feet long, steel 
>> cored copper, brand named originally COPPERWELD.  The strrel core is to 
>> allow driving the rod into soils that aren't always easy to drive into - 
>> like the clay and shale here in Virginia.
>>
>> Minimum of four ground rods, preferably ALL bonded together below the 
>> surface of the soil with at least 1/4" copper conductor.
>>
>> In a power plant or substation we ALWAYS used a "grid" of 500 MCM bare 
>> copper between all grounds.
>>
>> This will provide a Great counterpoise AND a very good ground for the 
>> home itself.
>>
>> Bob - N0DGN
>>     
>>> I'm not in that position at the moment, thank goodness, but I'd think
>>> that the more copper straps or braids you could put down to ground rods,
>>> the better. All of them loop-and-bend-free, of course, to keep the
>>> inductance as low as possible.
>>>
>>> Do please let us know what your results are, as you continue in this
>>> investigation. 
>>>
>>>   
>>>       
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|             AM Amateur Radio Operator    NØDGN                   |   
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| Bob Bethman                \\\|///     " The absence of a danger |
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