Grant, interesting link on copper corrosion. The use of salts, including
table salt (sodium chloride) has been suggested as well as sulfates such as
Epsom Salts to improve the conductivity between grounding structures (ground
rods etc.) and the soil. The copper corrosion write up mentions chlorides
and sulfates in the soil as sources of corrosion for copper. Another one of
those things that make you go hmmm. What is better, corroded copper in soil
seeded with sulfates and or chlorides or or lower conductivity soil with
less corrosion on the copper?
Why the affinity for Cadweld in the NEC? One possible explanation is that
the NEC has to be applied by the rank and file of the electrical tradesmen.
Cadweld gets good results with minimally trained and experienced personnel.
The connections can be inspected satisfactorily by marginally trained
personnel.
Patrick AF5CK
-----Original Message-----
From: Grant Saviers
Sent: Friday, May 10, 2013 12:05 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Fwd: Grounding of tower
Brazing works to steel as well as Cu, with the use of flux on the
steel. On Cu, Ag/ P (Harris Stay-Silv 15) containing brazing alloys are
self fluxing and are pretty much the standard for HVAC and refrigeration
piping. Georgia Copper sells it specifically for ground system
brazing. http://www.gacopper.com/BrazingRod.html
Cadweld probably gets the nod for few-off rods and for many joints or no
Cadweld form, brazing.
Silicon Bronze can be used for steel to Cu MIG welding.
Interesting link re corrosion of Cu underground and how to protect it.
http://www.copper.org/resources/properties/protection/underground.html
Grant KZ1W
On 5/9/2013 8:52 PM, Jim Lux wrote:
On 5/9/13 9:06 AM, Al Kozakiewicz wrote:
The point was that burying brazed joints is common accepted good
practice. AM broadcast ground system are designed for a 30 year
lifespan. That being said, brazing copper wire to a copper clad steel
rod is still bonding Cu to Cu regardless of the substrate.
Me, I'd use Cadweld - best practice - for buried ground rod connections.
The notion that an individual can second guess years of experience behind
the code and do it better is hubris.
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