Peter Wiley wrote:
In article , Jim Stewart
wrote:
Jess wrote:
Hi all,
I would like some help / advice in outfitting my shop.
For the first time in my metalworking home shop, I am able to get 3
phase service from the local power company.
In the past, I have always used a 3 phase rotary converter that I
built with the help of the group here - special thanks to Fitch and
Bob Campbell.
My question is, which voltage should I specify - and why?
I can get 208v, 220v or 440v.
What are the pros and cons, if any, between the choices?
If it's just a home shop do not get 440v.
You're out of the realm of do-it-yourself
electrical work and accidents involving 440
are *not* fun.
My shop is wired 415V 3 phase. Did it all myself with an inspection by
the electrical contractor before the sub board was 'hot'. Can't see
it'll kill you any deader than lower voltages. I did it all to code
because *I* was the one going to be using it.
First of all, I'm no expert and I'll certainly
defer to the pro electricians in the group.
That said, 440/480 is uniquely dangerous in it's
ability to sustain a plasma fire without tripping
upstream breakers. A screwdriver dropped onto
busbars can evolve into something that will burn
your arm off or worse.
I think the electrocution risk is substantially
greater than 240V as well.
Then again my single phase supply here in Aus is 240V, so I think our
general wiring standards are waaay tighter than yours. When I lived in
the USA a few years ago, at least, the general wiring standard,
frankly, sucked.
Part of the problem is that standards enforcement
is primarily a local issue. I agree that stuff
like using a clothes dryer ground lead to pull
current for the motor or lamp is pretty much
nonsense.
I wired my garage subpanel myself as well. When
I call the city inspector to sign it off, he said
"You must have done it yourself, it's too neat for
an electrician.
Get the supply you think is going to be most useful for the size motors
etc you're going to be running and do it to or above code requirements.
PDW
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