Jim Brown wrote:
>On Sun, 04 Mar 2007 13:50:34 -0600, Kim Elmore wrote:
>
>>I've gone to some pains to isolate my station RF ground from the
>>mains ground and it isn't always straightforward...
>
>This is a VERY BAD thing to do. ALL grounds within a building, MUST,
>by LAW be BONDED together by a low impedance path (that means BEEFY,
>DEPENDABLE, and SHORT). This is a requirement because it is the
>SAFEST thing you can do, both for lightning safety and safety for
>personnel. If this doesn't work for you, you need to fix your
>station, especially your antenna system.
Let's be careful here. "All grounds within a building," as stated above,
seems rather too sweeping.
I had understood the requirement in the USA to be as stated by W8JI last
night: "NEC prohibits multiple independent grounds on systems ENTERING
the house". That is very different from Jim's wording of "grounds WITHIN
a house."
Using the drawing at the top of Tom's "Grounding" page
(http://www.w8ji.com/station_ground.htm), the NEC requirement seems to
be that if you install a new ground for your radio, that comes into the
house at B, there must also be separate ground bonding OUTSIDE of the
house, running from B to the service entrance at C.
In the USA, must this B-C conductor always be a buried bare wire - in
other words, helping to reduce the ground impedance?
(The reason I'm asking is that similar bonding is also required in the
UK, but it is allowed to be an insulated conductor running through the
house - which is OK for AC safety, but a Very Bad Move for RFI and
lightning protection.)
--
73 from Ian GM3SEK
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