240V wiring question

I'm rewiring my TS for 240V...the motor is easy, since the diagram is right there on the case. However, the switch has left me with one question. I picked up a GE CR101 motor starter switch (ebay) and mounted an additional box on the front of the TS to hold the switch. However, there is no ground screw on the switch...unlike virtually every other box-mounted switch I've had in my hands. There are three terminal pairs on the switch...but I believe the 3rd terminal is for 3-phase power and that the ground wire should NEVER be switched.
There are screws holding the switch casing together that contact the front plate, so I'm thinking that the ground wires from the power and the motor should be tied together with a wire to this screw on the switch and another wire to the cabinet of the saw. Sound right?
TIA, Chris
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Chris Merrill
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Need some care with the terminology here.
Have to differentiate between "neutral", and "ground". Neutral wire is white; ground is green or 'bare'.
"Ground" is *NEVER* switched.
"Neutral" is usually _not_ switched, although *if*done*correctly* it is safe to do so.
"Neutral" is *NOT* to be tied to 'chassis' or other grounding point, except at the main service entry point.
"Ground" is intended to be connected to chassis/frame, etc.
I suspect you were calling the white wire 'ground'.
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You don't have a neutral with 240V. You have two hots, both switched, and ground. If you hook up with conventional romex house wire, You'll have black and white. It's common to put some colored tape on the white at the emds, to signal that it's a hot wire. Ground connected as described.
Be sure to use the set of contacts that are connected to the coil, otherwise the relay won't pull in. One set will remain unused, if you really have a 3 phase starter. Wilson

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Common? I should hope so! Isn't it required by code? Not to mention common sense?
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wrote:

Nope. None of mine are marked.
You look in a breaker box. You see a white stuffed in a breaker that has a common trip. You says to yourself, self, that is a 220. The white be hot! No problem here.
You goes to the other end of the wire, where it terminates in a box with only one circuit, and has a funny lookin outlet, with prongs sideways, and all. You says, self, this here be a 220 outlet, and when you opens up the box, you see a white and black on the receptacle. No problem here.
See, even I didn't get cornfused, and I ain't the brightest bulb in the string! :-)
Seriously, the only thing that needs to be marked is the white neutral coming from your meter to the breaker box. And then that is usually black wire with white tape or paint added to it.
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wrote:

More common to mark a white as hot, when multiple circuits are run in conduit.
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if you are running wires in a conduit then they would be single strands and you would not run a white one, just multiple pairs (or 3s) of colors.
BRuce
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<BRuce> wrote in message

Right, and I almost went there, and decided not to.
I have seen it done, where machines were being relocated, and a 110 needed to become a 220, so rather than re-pull a new colored wire, a white was marked with a piece of color tape at the box, and at the panel, and a new double pole breaker installed with the color tape and the black wires.
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snipped-for-privacy@horatio.agresource.com wrote:

AFAIK, I used all correct terminology...

If I understand correctly, there is no neutral on a 240 circuit.

That's what I said, right?

I thought that was part of the reason for using a 'motor' rated switch - because it switches both lines off (called a double-pole switch?).

Again, I don't think there is a neutral on a 240V circuit.

No...I was calling the green wire ground. The white wire is hot, in this case, as well as the black wire.
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There is an interesting opportunity for the original poster, now that he has a magnetic starter. If you want to, you can add a 110 volt box on the side of the saw, and have it hot when the starter is pulled in. Then you will have to have a neutral, and a 4 prong plug.
I did this, so I could run a shop vac to the top of the guard, and catch most of the dust coming off the top of the blade.
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Morgans wrote:

That's a great suggestion, except I've already got a remote-controlled DC. Might work well for someone else, though!
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I many times do not start the DC, if I'm going to make a couple quick cuts. Then the vac does the job, and always ready.
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Morgans wrote:

I guess I'm missing your point. If you're going to make a 'couple quick cuts', you use the vac instead of the DC? What is the point in having both? Sounds like a pain to have both a DC and a vacuum hooked up to the TS. If you have a DC, why not split a smaller hose to the blade guard?
BTW, I am installing a "motor starter switch", not a "magnetic starter". I'm not sure if that affects your original comment, but they are two distinctly different things, as you are probably aware.
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a little more. For a couple cuts, you can wait until the next time the DC starts to get that.
Why I don't split off from the DC? A had a vac sitting around doing nothing, and under the saw table was a good place to store it, then if it's under the saw, why not put it to use? Plus at the time I didn't have a remote DC switch. I see the switch instead of magnetic starter now, but you could still do this with the switch, and adding an un switched neutral wire.
Speaking of remote DC switches. I did a REAL Rube Goldberg to get a remote for the DC at the school shop, where I teach.
I had an old garage door opener that the father in law gave me for parts. I got a couple single pole, double throw micro switches, and put them in the unit, so that when the opener was cycled, and the limit screw and contacts moved, it would hit either switch at the end of the travel. One switch I wired so that the normally open got closed, and would energize the "hold in" circuit on the magnetic starter, then the contactors on the starter would also be holding it in. The other switch was wired so the switch at normally closed would open when the screw traveled, and break the starter's hold in circuit, to shut it off. Everything is neatly inside the box, away from prying hands, and it is working great!
Part of the complication of wiring it this way, was so the DC could also be started from a different shop. A bonus is, that once I have turned it on, the kids in the other shop can't turn it off, like they used to do!
Anyone top that for a Rube Goldberg? :-) I'm sure someone can!
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Listen to what he says.
Above all, don't be an idiot and wire your garbage disposal switch so that it switches neutral.
It might appear to work, but strange things will happen if it shorts out.
DAMHIKT.
--randy
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After I moved in to my current residence, SHMBO asked me to remove a broken light bulb from the chandelier. Darned If I didn't get zapped. I double checked the light switch (I was quite sure it was off since the other bulbs were not lit). After some investigation, I found that the previous owner ( I sure hope not an electrician) had switched the neutral rather than the hot.
In my experience, almost without exception, strange electrical behavior can usually be traced to a neutral problem
-- Al Reid

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DCorrect! Wire nut the motor's green to the power cord green, and to the box (with a pigtail, if the box is metal). Then connect two power cord wires (black) and (red) to the LINE side of the switch, and the two hot motor leads to the LOAD side of the switch. The power wire should NOT be HOT during this installation! Unplug it, or pull the fuses, or turn off the disconnect switch.
Chris Merrill wrote:

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Bob Walters wrote:

Thanks for the confirmation. After reading the previous answers, I was starting to believe nobody understood the question...or I was drunk when writing it ;)
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yep, you are correct.
BRuce
Chris Merrill wrote:

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You are correct on all accounts
Ms Leslie

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