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Posted by Winston on April 30, 2008, 1:35 am
Please log in for more thread options grumpyoldhori wrote:
> Don Foreman wrote:
>
>
>>37 ohms per km of 4 mm iron/steel wire strongly suggests a splice
>>that may be mechanically strong but has poor conductivity due to
>>corrosion.
>
>
> Yes, good point, I will put 4 mm copper wire jumpers
> across all splices.
Better to carefully clean and solder the steel splices rather than
have current going through dissimilar metal junctions.
This stuff is rusting away quickly enough. No need to speed up
that process.
Remember the flux! Remember to clean up with alcohol!
> What figure should I be looking for on a km of 4 mm
> steel wire in ohms ?
Say 14.75 ohms for a km as a guess.
So a two wire loop of 1 km would total about 29.5 ohms.
--Winston
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>
> May I thank all that gave me advice on this.
> Went out today and we insulated wires two and three
> from the top by using some plastic conduit that we
> cut so as to slip it over before refastening the
> wires to the posts.
> Oh, and we insulated the wires of the posts at both ends.
> Luckily this is a straight run fence, no gates or corners.
>
> Put a jumper across the wires at the top of hill and got a reading
> of thirty seven ohms.
> So have decided to follow Spehro's plan and use two of
> these http://www.jaycar.co.nz/productResults.asp?FORM=KEYWORD
>
> And use the Linksys wallwart as well.
> Am I right in believing that using two wires up and two
> down would drop the overall resistance to eighteen ohms ?
> Thanks again.
>
>
>