As I've slowly started to replace my questionable tools with bigger/
better/faster, I've generally switched to 3 phase (table saw, planer,
jointer, dp and dust collection are all 3 phase now). To this point I've
just hardwired everything to an increasingly ugly panel of fuseboxes.
I'll be installing a full blown 3-phase breaker panel in the coming weeks
and removing all the fuseboxes, save for the main 200a disconnect. Here's
the major question though: What type of outlets/plugs are generally used
for 3 phase? Do most people hardwire everything? There seems to be very
little if any standard 3 phase plug, and I'd be fine with my tools not
being portable (who wants to load the 400lb unisaw?..). I have some
hubbell plugs that came on a few of the tools (almost all bought used,
almost all older than I am), so that's where I'm leaning, but they are
What type of plug/outlet would you suggest? Should I stick with
hardwiring for the majority of tools and just use something like the
hubbell plugs for the ones that need to be somewhat mobile? Is there some
Knowing what type 3 phase will make answering your questions meaningful.
Doesn't look like you are in Canada, so forget the 575V.
As you can see, it makes a difference.
Super, you have it made in the shade.
Get a 3PH, 4W panel board for your distribution panel.
I'd use a separate 3P c'bkr for each fixed tool (saw, shaper, plasner, etc)
Mount a 3P, non fused, safety disconnect switch on the wall within 10-15 ft
of the tool and hard wire from the tool to the disconnect switch with a
piece of SJO cord.
You can now padlock the safety switch in the off position when you want to
work on the tool.
Since you will be operating tools that will only operate at 240/480VAC, it
will be necessary to add small buck-boost transformers in order to be able
to operate a 240VAC tool from a 208Y supply.
Any decent electricasl supply house will have buck-boost xfmrs in stock and
can select the proper size required, if you provide the amps @ 240 VAC
Mount the B-B xfmrs at the safety switch location.
Forget about plug/receptacle for these loads, a non fused safety switch is
only a more reliable installation, but will probably be less costly.
That's not 208 Y , it's split phase Delta and it's 240 V phase to phase in
the USA and not 208 V . You have to be careful which phase you use when
hooking up something between one phase and neutral for 120 VAC as that
voltage is only available from two of the phases. 208 Y ideally has the same
voltage from each phase to neutral. For 3 phase needs split phase delta
works fine, but never connect voltage sensitive 120 volt equipment to it
without making sure that your wiring is correct. Measure the voltage before
plugging something in the first time that an outlet is going to be used.
Also check to be sure that 3 phase equipment can run on 240 V before
connecting it.....There is a significant difference between 208 Y and 240
split phase and some equipment cannot handle it. All 3 phase is NOT the
There are more "wild leg" or "split phase" (also known as "high leg" and
stinger leg") out there than there are 208 Y systems. Some electric
companies prefer one over the other, but you can find both almost anywhere
in the USA. There are several other methods of delivering 3 phase power, but
these are the two that are most common "point of use" versions in the
USA.The next most common on the list is probably the grounded leg delta
system. The lowest voltage commonly available is 240 phase to phase but in
this version one of the legs is grounded, so you measure 240, 240, and 0
when measuring between each of the phases and ground. You can't get 120 from
this one without a transformer no matter how you try to hook up to it. The
electric companies use it a lot for their main transmission lines and for
delivery to larger customers who have their own transformer substations.
With the right transformer you can convert any 3 phase system to whatever
other 3 phase system that you need or prefer. The cost of these transformers
makes doing this prohibitively expensive for a small customer, but the
larger 3 phase power users do it all the time. One part of a plant might
have one type of 3 phase while another will have something different. It all
depends on what the needs of that area of the facility are. They will likely
also have additional transformers to supply 277 V for industrial lighting
requirements and 480 V 3 phase for larger machines and furnaces, plus 120
for the office areas, all supplied via trasnsformers from the main 3 phase
electric service which is probably 14.7 KV 3 phase or higher.
I never realized that so many methods of delivering 3 phase power existed in
this hemisphere until I began installing European made printing presses in
all 50 States and the Carribean Islands. Everywhere that we had to install
one of these presses it was my job to figure out what power was available at
the location and then figure a way to make it power the new presses. At a
few places I even had to make 3 phase power from single phase. Since these
presses were manufactured to run on 220 V 3 phase Y connected 50-60 cycle,
there wasn't any place in this hemisphere where we could simply just plug
them in. A 208 Y service needed boost transformers to raise the voltage to
220 and a 240 Delta service needed to be converted to a Y service as well as
correcting the voltage down to 220. Fortunately, the presses were designed
so they would run on either 50 or 60 cycle power or my job would have been
Think I will have to take exception on that one.
I've been out of the electrical business since the early 80's;
however, NONE of my electrical consultants were designing anything but
Y systems, even back then.
One local utility still had some isolated locations but were phasing
None of the Rural co-ops had any that I ever ran across.
The advantages of being able to create a known ground fault current
when a fault occurred, thus you could deal with it in a safe way made
a "Y" system a no brainer, even back then.
Still remember the Rube Goldberg schemes used by the automotives to
indicate grounds in their 120V control systems.
Wire two (2), 240V pilot lights in series with the center tap grounded
and the 120V control circuit ungrounded at the control x'fmr.
In the event of a ground, one of the pilot lights would go out,
indicating which leg was grounded.
It worked, after a fashion, keeping those production lines going 24/7
for a lot of years.
I could understand if some of the smaller rural co-ops located out in
the boonies still had some wild leg delta running, but not in a major
BTW, can relate to what a total PITA trying to install European
equipment operating on 380/220/3PH/50HZ in a 480/3PH/60HZ world can
Early in my career, faced just that problem.
Solution was not to buy European equipment without European electrical
equipment, then finish it out over here.
I prefer Y systems too but, when in the installation business, you have to
deal with whatever system the customer has in their location and find a way
to make it work. I was the only electrical factory service rep. for North
America for that European press company, so they expected me to just "deal
with it" and make their product work no matter where they sold it. I also
occasionally had to come up with very creative ways to correct design
deficiencies in new models of the presses, while somehow keeping the
customer a bit in the dark about what I was doing. Most of the time the
factory was just interested in making more and didn't care if they shipped a
few quality nightmares every now and then. Unless it was a total show
stopper they just stuck me with figuring out how to make it work.
The relevant standard is http://www.nema.org/stds/wd6.cfm . I believe
that one of the four-wire outlets (3 phases plus safety ground) is
required, but I don't have the code handy. Also check your local code
on the odd chance that it requires something different from NEC.
Use a plug. You want the power off to the machine whenever you're
changing blades, knives, or whatever or have your fingers in the
belts. The power switch alone is not enough--they've been known to
fail _on_ and there's always the chance that your kid or one of his
bratty friends will say "what does this do" and hit the switch at the
worst possible moment. The power switch and the breaker will do from
that viewpoint but using the breaker has several disadvantages:
One is that it's easy to hit the wrong breaker.
Another is that even if your shop is meticulously labelled, if you get
in the habit of using the breaker as the safety shutoff then one day
you'll be in someone else's shop and he'll have it labelled wrong
(I've seen _far_ too many mislabelled or unlabelled circuits).
Another is that if you have to go more than three steps to pull the
breaker odds are that you'll get sloppy about using it. The cord
should be plugged in within six feet of the machine so that's less
likely to be an issue. (note--if you're putting in outlets for the
machines, place them where they are going to be quickly reachable for
Another is that the unplugged cord gives you immediate visual feedback
that the tool is cold.
In addition to this, I would suggest that you replace your fuse panel(s)
with 3 phase breakers. Using fuses on 3 phase equipment is not a good idea
as loss of a phase due to a blown fuse could result in loss of the motor
being powered by it. 3 phase motors don't like to run on 2 phases and the
loss of just one motor could cost as much as a whole panel of breakers. 3
phase motors also each need overload protected motor starters for further
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