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Re: [Amps] Safety grounding - was Mains Isolation Transformer

To: amps080605@w4zt.com, amps@contesting.com
Subject: Re: [Amps] Safety grounding - was Mains Isolation Transformer
From: Gudguyham@aol.com
Date: Tue, 4 Jul 2006 12:18:12 EDT
List-post: <mailto:amps@contesting.com>
In a message dated 7/4/2006 10:12:30 A.M. Eastern Standard Time,  
amps080605@w4zt.com writes:

Lou,  that wouldn't necessarily be true.  If you had a 240 Volt device
that  didn't have any 120 Volt needs at all, you would still HAVE to use
that  plug to get the power from the generator.  In that case,  two
conductors would have zero current. You either put the correct 4  pin
plug on your three wire cord or make an adapter.
STRICTLY SPEAKING A DEVICE THAT REQUIRES NO NEUTRAL AND IS 240V WOULD ONLY  
HAVE A 3 WIRE PLUG ON IT.  YES, YOU ARE RIGHT, YOU WOULD HAVE TO MODIFY THE  
PLUG ON THE DEVICE OR MAKE AN ADAPTOR, IN WHICH CASE YOU WOULD NOT USE A 
NEUTRAL 
 WIRE, ONLY A BOND.



There are hundreds of thousands of 3 wire 240 Volt receptacles  in use in
the USA today that are still legal until someone makes a wiring  change
that requires an upgrade to meet code.  Code changes don't mean  that
existing wiring is illegal or unsafe. The change in code was to  strictly
meet the need for handling both 240 Volt and 120 Volt loads from  a
single receptacle and still provide the bonded safety ground. It  has
nothing to do with what we really CAN do both safely and legally.  Even
if you have a 4 wire receptacle, you can still use only 3 of them  if
your load doesn't need the neutral for a 120 Volt current path. Leave  it
off the plug or don't connect it in the device, it's all the  same.

73, Tony W4ZT


TONY, WE ARE SAYING THE SAME THING, HOWEVER IF ONE WAS CONFRONTED WITH SUCH  
A SITUATION AND DECIDED TO USE A CABLE WITH 4 WIRES AND THEN ON ONE END  
CONNECTED THE NEUTRAL TO THE BOND, THAT WOULD BE A VIOLATION.  BEST TO USE  3 
WIRES 
AND LEAVE ONE CONNECTION ON THE GENERATOR END (NEUTRAL) NOT CONNECTED.  YEARS 
AGO WHEN OVENS WERE STRICTLY 240V A 3 WIRE SYSTEM WAS USED, THEN LATER ON  
WHEN THEY ADDED CLOCKS AND TIMERS WHICH USED 120V, THEY GROUNDED THE 120V 
DEVICE 
 TO GET THE 120V NEEDED.  THE PROBLEM CAME WHEN POOR CONNECTIONS ON BX CABLE  
THAT WERE ONLY HELD WITH HICKEY FITTINGS OR THE LIKE GOT LOOSE OR CORROSION 
ON  IT AND DUE TO THE FACT IT WAS CARRYING CURRENT WOULD SPARK AND CAUSE  
FIRES.  CODES USUALLY CHANGE BECAUSE OF SOME SAFETY ISSUE HOWEVER  REMOTE.  LOU
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