[TowerTalk] Dissimilar Metals?

[Bill Hider (N3RR)]

Eric,

Here's what you do:

Aluminum to aluminum is OK.  So the ICE/PolyPhaser units bolt directly to
the panel.

Alternatively, if the panel is steel, mount the aluminum ICE/PolyPhaser
units to it, but use a stainless steel bolt/lock washer/nut.  That is the
grounding mechanism for the lightning arrestor.  This stainless steel
combination becomes the electrical connection between the panel and the
arrestor.

The copper ground wire should be connected to a copper ground lug that is
mounted to a stainless steel bolt and sandwiched between two stainless steel
flat washers so that the copper part touches only the stainless steel parts.
This bolt is mounted/grounded to the steel (or aluminum) box.

Signal cables will have passivated connectors either brass or plated with
nickel, silver, or other passive metal.  These connectors are screwed
directly to the ICE/PolyPhaser aluminum units.

Yes, there will be a problem with copper connected to aluminum.  Avoid this
with the stainless steel bolt/washer combination.

Brass and copper is "OK", but I avoid it.  I usually use stainless steel as
the transition metal between two dissimilar metals.  That stainless steel is
usually a bolt/washer/nut combination.

73,

Bill, N3RR



-----Original Message-----
From: owner-towertalk@contesting.com
[mailto:owner-towertalk@contesting.com]On Behalf Of Eric Rosenberg
Sent: Thursday, January 10, 2002 11:20 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Dissimilar Metals?



I'm putting together a Single Point Ground system and exterior box for
connectors, et al.

I'm concerned that there will likely be dissimlar metals involved --

The lightning arrestors (ICE and Polyphaser) are aluminum, the
grounding wires and cables are copper, and the panels for the box's
interior panel is aluminum and I can make ht eSPG whatever I want.

My questions are this...will there be a problem with aluminum and
copper being bolted together?  Should I go to another metal?  What
happens with brass and copper?

Thanks in advance,

Eric W3DQ
Washington, DC


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________________________________________________________________________
This list is sponsored by the new eHam.net Store.  When you buy products
like ICE filters, Array Solutions StackMatch, or M-Squared Antennas from
the eHam Store for the same price you pay direct, a portion of the sale
price goes to support this list.  Check it out at http://www.eham.net.

-----
FAQ on WWW:               http://www.contesting.com/FAQ/towertalk
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com