[Amps] Transformer question

[Tom W8JI]

> 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.
Jim,

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