[Amps] what is a 4 wire 240VAC service?

[Jim Brown]

On 4/3/2011 12:08 PM, Al Kozakiewicz wrote:
> For amateur amplifiers that run ONLY on 240V, 4 wire service should not be required by code or UL.  The neutral is only for safety and does not carry any current except in the case of a failure.

This is bass akwards.  A power that runs on 240V MUST draw power between 
the two sides of 240 volts. NO NEUTRAL CONNECTION IS NEEDED UNLESS that 
power amp also needs power at 120V (typically to run a 120V fan).  The 
ground (Green wire) is the SAFETY ground, and must be connected only to 
the enclosure.  The primary of the power transformer MAY have a center 
tap, but it MUST NOT BE GROUNDED.  The center-tap COULD legally be 
connected to a neutral, but there is no good reason to do so.  Further, 
it is a SERIOUS violation of safety codes to connect Neutral to ground, 
AND A CAUSE OF NOISE, HUM, AND RFI,

PLEASE study either NEC or my tutorial before you spread any more 
misinformation.

73, Jim K9YC