On Fri, 23 Jun 2017 17:28:07 -0400, Roy Biggins
wrote:

On 6/23/2017 5:06 PM, Boris wrote:
I read all your replies (thanks), and understand the the differences
between 3- and 4- wire 220v circuits. Every home I've lived in, so far,
has been built before 1996. As time goes by, codes become more and more
stringent, sometimes benefiting the end user, sometimes just the
contractor/manufacturer. But, I can definitely appreciate grounding a
steel cabinet to a home's ground.


Ground and neutral are bonded at the service entrance so no need to waste extra copper on a 4-wire circuit.
True if everything oes according to plan. What happens if your neutral
fails? Being a 240 device, everything still works - unless there is
aome 120 components (like the interior light, or the timer) in which
case the case becomes live.
There IS a GOOD reason 4 wire is now required by code. get used to
it.