[Amps] Transformer question

jeremy-ca km1h at jeremy.mv.com
Sun Jul 8 13:40:53 EDT 2007


> Not only that, it is illegal and a shock hazard to use the
> ground wire as a neutral. You would need a four wire outlet
> or otherwise somehow ensure the power return neutral was
> isolated from the chassis.

So then why do amps that offer 120/240 VAC options do it that way?

The NEC manual for Resedential Wiring requires both a neutral and a ground 
at the panel as well as in the distribution wiring. For a 240V outlet the 
ground is terminated along with the ground at the outlet box.
For 240V circuits that power equipment using 120 and 240V items the NEC 
manual CLEARLY states and shows both the neutral and ground wires going to 
the same plug connection in a 3 wire outlet. It further shows the 120V leg 
split off the 240V in a typical dryer circuit using the neutral/ground. This 
one leg controls the motor and lights which would draw more current than a 
1500W ham amplifiers 120V components.

Further, balance is not required on the 120V legs unless the current load is 
a substantial part of the total. NEC gets into this a bit with a 70% 
statement.

When I completely wired my current home I followed the NEC code and had no 
problem with any level of inspection  including many 240V outlets in the 
shop, shack, and garage.

Carl
KM1H



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