[AMRadio] 220 vac line

[rbethman]

Yes, not REALLY for lightning.  Want to see funky ground requirements?  
Take a look at the ground running from the top of your chimney.  What 
pray tell was THAT designed for?  It is Aluminum, about #8, and goes to 
a ground rod on the OTHER side of the house from the service entrance!

Lightning protection is *essentially* left to the power grid!

That is why they have all the lightning arresters.  We don't have 
ANYTHING that can handle 50,000 Amps & at WHAT VOLTAGE?

Bob - N0DGN

On 7/27/2011 2:37 PM, Bernie Doran wrote:
> I beg to differ on earth ground being there for lightining, A typical bolt
> is 50,000 Amperes,.  a typical earth ground is 10 Ohms or more, NEC says 20
> Ohms is OK.   even with 10 a Ohm ground that is 500 KV above ground, how
> many feet away from your   "grounded"  equipment do you want to stand?
> ----- Original Message -----
> From: "Gary Schafer"<garyschafer at comcast.net>
> To: "'Discussion of AM Radio in the Amateur Service'"
> <amradio at mailman.qth.net>
> Sent: Wednesday, July 27, 2011 11:16 AM
> Subject: Re: [AMRadio] 220 vac line
>
>
>> Neutral must be grounded to earth at some place in your power
>> distribution,
>> usually at the service entrance panel.
>>
>> The SAFETY ground wire (bare or green) must also be bonded to the neutral
>> somewhere in the system, usually at the service entrance panel.
>>
>> If the hot wire should touch/short to the chassis the safety ground wire
>> becomes the return path for the current back to the neutral at the service
>> panel to ensure that the breaker will trip.
>>
>> The EARTH ground rod(s) are bonded to the neutral and safety ground wire.
>> Earth ground is not there to trip the breaker in case of a fault. Earth
>> ground is there for a lightning path and to prevent stray currents on
>> equipment.
>>
>> 73
>> Gary  K4FMX
>>
>>
>>>   Regarding the neutral, remember that is the wire that runs to the
>>> centertap
>>> on the 240 volt secondary service, that must be a solid connection to
>>> maintain the 120 each side of the line. The ground may or may not be
>>> connected to the neutral and is almost never a good ( low impedance)
>>> ground.
>>> The typical 8 ft ground rod is simply terrible, frequently 20 Ohms or
>>> so. If
>>> 120 goes to the
>>> "grounded" chassis it simply flows 6 Ampers or so to ground and the
>>> chassis
>>> would be at 120 volts.
>>>   My ground circuit here is eight 8 ft rods under and spread around  the
>>> footer all bussed together with #4 Cu, another #4 goes to the big ground
>>> rod, 5 inch pipe 180 feet deep.  measures about one Ohm. The main panel
>>> has
>>> a big fat MOV block on the secondary side of a 60 Ampere breaker.
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|               AM Amateur Radio Operator    NØDGN                 |
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| Bob Bethman                \\\|///     " The absence of a danger |
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