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Re: [Amps] 220V service for amplifier

To: jsb@digistar.com
Subject: Re: [Amps] 220V service for amplifier
From: ka1xo@juno.com
Date: Wed, 3 Dec 2003 07:24:33 GMT
List-post: <mailto:amps@contesting.com>
Dear Jason,

On your amplifier there will more than likely be an attachment
to the metal box where a grounding conductor can terminate.

The metal frame of your amplifier should have an independent
grounding connection to a known and verified earth ground where
the earth ground connection is tied in with the primary a.c. electrical
ground in your service entrance.

The metal box grounding provides you with two different protections:
 In the event of the failure of the a.c. electrical ground the frame
 of the amplifier will not become energized, and,
 In the event of a static surge travelling along coax shields, etc.,
 the frame ground conductor will drain the charge before it makes its 
 way through the circuitry of the amplifier to the a.c. electrical
 ground connection within.

The external grounding connection also serves as a drain for RF voltages
appearing on the case of the amplifier, so it might be said that the
frame ground provides three separate and distinct levels of protection.

In my shack I use a size 1/0AWG WELD type cable as the frame ground 
feeder. The 1/0 WELD cable has many, many fine wires, all of whose
skin conductance on their outer one-molecule of copper happily convey
fault, static and RF away from the gear. The reason I use such a large
diameter wire is to reduce the voltage drop between the equipment and the 
ground connection (a clamped water pipe with a jumper to the aceg).

Places like Graybar Electric carry the wire and the appropriate tin plated 
compression lugs to fit the copper in.

Hal,
KA1XO/2
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