OK, here's my 2 cents worth:
Since you will be using both 240 and 120 (phase to neutral), use a 4
wire plug, or as a much less desirable alternative use 3 wires and make
sure the chassis is always connected to earth ground. DO NOT connect
neutral to your chassis at your equipment. Neutral and ground are the
same potential at your service panel, but not necessarily so at the
equipment. Ideally no current should be flowing on the ground
connection (since it's no longer ground then is it?, since you are I*R
volts above ground at your chassis).
If you were running only 240, and not using 120 phase to neutral you
could get by with a 3 wire plug.
Also, as a point of reference, code for new clothes dryer wiring
requires a 4 wire outlet. I had to break down (no pun intended) a new
dryer a couple weeks ago.
73
Jim W2RA
> -----Original Message-----
> From: Ron Hooper [SMTP:ab4ru@stc.net]
> Sent: Tuesday, December 22, 1998 6:40 PM
> To: amps@contesting.com
> Subject: Re: [AMPS] Line input wiring
>
>
> > >I'm wiring my new ham shack and am confronted with several
> different
> > >240V outlet types, some are 3 wire, and some are 4 wire.
>
> Use 3 wire Plugs. You will find several different configurations but
> if
> you notice on the plug it will have a voltage/amp rating. Make sure
> your
> plug is rated for 240 and has the proper amp rating for the amp's
> current rating. The 4 wire versions are for 3 phase or special
> applications on specialized equipment using a neutral seperate from
> the
> ground.
> > >
> > >The question is: What is the number of wires in the typical
> commercial
> > >amp power line cord, one that should be run on 240V?
> > >
> > >I'm presently using a 3 wire input to my amp, which operates on
> 240V.
> > >The neutral line connects to the low side of the amp control
> circuitry
> > >which needs 120V. Chassis is connected to the station earth
> ground.
> >
> All the amps I have used on 240 volts, single phase, have been 3 wire.
>
>
> > >Should I use a 4 wire outlet and bring the power line ground from
> the
> > >breaker box to connect to the amp chassis?
>
> Its not necessary if you ground the chassis to the neutral in most
> cases
> here in the states. If you were in Europe or some other countries
> around
> the world, the 4th wire is a requirment to meet standards. It would
> basically be connected to the same terminals as the neutral in the box
> and serves as an ADDITIONAL ground in case the other one breaks or
> comes
> loose. You only have 3 wires coming in your house now. There is more
> to
> it than parrelling the ground wire but was trying to get the point
> accross.
>
> Ron
>
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