Thanks Gary, that explains a lot of the confusion I had.
I built this house in 89 and the NEC in force was the 1987 version. That
clearly showed the neutral and ground tied together.
I also checked my 1960's era Montgomery Ward stick welder and that is as you
described yours. Ive several 240V devices in the garage, each on its own
circuit back to the auxillary box in the garage. But that has its own 60A
line back to the house and the main box. Guess its time to check it all out
if only for curiosity. Ive not had a tingle "yet".
Ive never even (noticed) seen the 4 wire appliances mentioned. My guess is
that some member of a safety committee had a brother in law that made
connectors and they needed a new profit maker!
Now my next step is to see how I developed the 120V in my 1500W 2M amp which
was built in the 70's. I dont remember any "soft arm tingles" and each amp
plus work benches has a dedicated #10 line back to the main box.
Thanks to the many that offered constructive comments and not condescending
----- Original Message -----
From: "Gary Schafer" <email@example.com>
To: "'Tom W8JI'" <firstname.lastname@example.org>; "'Jim Brown'" <email@example.com>;
"'Amps Amps'" <firstname.lastname@example.org>
Sent: Monday, July 09, 2007 9:39 PM
Subject: Re: [Amps] Transformer question
>I just bought one of those 50A sockets for my welder last year from home
> depot. Sold as a range outlet. They still had the 3 wire cords for the
> there too. It is my understanding that the 3 wire circuit is still ok to
> for existing house wiring as there are still a lot of those circuits out
> there but any new wiring must be 4 wire.
> I just put in a new electric stove and a new 4 wire circuit for it. The
> stove has a jumper strap at its cord connection that is to be installed if
> you use a 3 wire cord and not used for a 4 wire cord. The jumper straps
> neutral and ground together for a 3 wire circuit.
> The older stoves and dryers had only a 3 wire circuit in them and it was
> intended that the neutral/ground be common.
> The NEC had exceptions for these two appliances to their "separate ground
> and neutral rule". But the stove or dryer using this exception had to be a
> dedicated line back to the fuse box. Nothing else on that circuit but that
> one appliance.
> Those are the only two appliances that I can think of that you could use a
> common ground/neutral on for 120/240 service. Everything else had to have
> the ground and neutral separate. Now the new rules for new wiring must not
> share ground/neutral on anything.
> However the old welder that I have, 3 wire circuit, does have a 120 outlet
> on it so for that it does use the ground as the neutral. It is from the
> 50's early 60's. I don't know if it was compliant then or not.
> Gary K4FMX
>> -----Original Message-----
>> From: email@example.com [mailto:firstname.lastname@example.org] On
>> Behalf Of Tom W8JI
>> Sent: Monday, July 09, 2007 8:12 PM
>> To: Jim Brown; Amps Amps
>> Subject: Re: [Amps] Transformer question
>> > However -- I have heard that there used to be some
>> > exception for
>> > certain heavy appliances. If that execption exists,
>> > perhaps
>> > someone could cite the specific paragraph.
>> It's my understanding the exposed case of large appliances
>> was never supposed to be tied to the neutral, but it became
>> so commonly misused it appeared many places.
>> They solved that problem in the mid-90's by mandating a four
>> wire plug for anything that uses 120/240. As a matter of
>> fact I tried to buy a 50A socket formerly common for
>> electric ranges at Lowes or Home Depot (for a welder) a
>> couple years ago and they told me I could no longer buy a
>> three pole 50A socket.
>> The important thing to remember for this discussion is while
>> some old ranges used 120/240 and may have tied the case to
>> the neutral, small appliances and devices using 15-30A plugs
>> never tied the neutral to the case. The is absolutely no
>> reason at all to do that in a Ham amplifier, and very few
>> commercial amps I've seen have ever done that.
>> 73 Tom
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