On 1/11/12 1:46 PM, Jim Brown wrote:
> On 1/11/2012 12:09 PM, Alan NV8A wrote:
>> That's the theory, and maybe it's*current* standard practice, but our
>> telephone cable comes in at the opposite end of the house from the
>> power, and the cable TV cable comes in at the back of the house.
>
> I had the same issue in Chicago.
>
>> I now have #6 solid copper running around the outside of the house
>> connecting them all together.
>
> Right.
>
> Bottom line -- keeping everything at the same potential is critical,
> and you can have as many ground connections as you like, but they MUST
> all be bonded together. That "MUST" is dictated both by the laws of
> physics and the law of the land (electrical building codes).
>
I think the relevant point is, though, that you don't need to do that
bonding with copper strap. Wire works just as well. The length will be
basically the same in both cases, and the inductance is basically the
same too.
Strap is for low AC resistance. Or for bridging a gap where you don't
want to leave a slot which might radiate.
Power line surges, lightning impulses, etc. are all low frequency enough
that inductance will dominate the AC resistance (as far as voltage rise
goes) with any reasonable sized wire.
Get up to tens of MHz and the situation starts to change.
You might also want to use strap in a situation where the mechanical
connection is easier.
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