Table saw conversion to 220v but 4 wire outlet

[Darcy Schaffer]

In my workshop, I already have 220 wiring that uses a 14-30R outlet (for modern dryer's I believe). I have a Grizzly GO771Z table saw that can convert to 220 just by switching the wires in the motor housing. There are four wires from the motor and 4 wires on the 14-30P plug (which I purchased for this use). The Grizzly wiring diagram just shows using 3 wires on the 220v plug.

Electrician's are very hard to find right now due to overwhelming demand in the city so I'm trying to do this myself. I realize there is inherent danger but the same could be said for many things I do :-)

Can anyone tell me how to connect the 4 table saw wires to the 4 outlet wires? The manual expects only 3 wires on the plug.

The manual shows the 220v wiring to be black and white from motor to white on plug and red and yellow on motor to black on plug. Green from the plug is connected to ground in the housing. There's no connection for the red wire on the plug so I'm not sure how to safely proceed.

G = green to ground
W = white wire
B = black wire
R = red wire (motor only)
Y = yellow wire (motor only)

Plug
G W B
| | |
| | |
| | |
X | |
| |
| |
/ \ | \
B W R Y
Motor

Thanks,
Darcy

[Tom Dixon]

Power coming in at the receptacle should be two hot leads and ground. A four wire outlet has two hot, one neutral and one ground. You eliminate the neutral both at the plug and the panel. What are the color of the wires at the receptacle? My guess is the two hot are black and red, the neutral will be white and the ground either bare or green. In some cases in 4 wire romex the ground can be a lesser guage so if that is the case I would swap the white wire for the ground both at the pug and panel. I would also recommend using a locking L6 style receptacle and plug of the correct amperage for the motor. Considering that it is currently wired for 110 I suspect it is either a 15 or 20 Amp circuit. If that is the case you should also replace the breaker. If it is a 20 amp motor you will need a 20 amp double pole breaker, a L6-20R and a L6-20P.

[Steve Fish]

If I’m looking at the correct document, it shows a 6-15 plug/receptical.....old school 2 hots and a ground, no common t) I hope Frank comes to the rescue on this one. My advice would definitely not meet any codes but I’m pretty sure what you have on hand will work.

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ETA- I believe Tom has it right

[Paul F Franklin]

You can not use a white wire for ground, ever. Ground wires must be bare or green or green with stripe.

If I follow OP's question, he wants to remove the current plug on his saw and replace it with a 14-30P to connect to receptacle he already has in place and wired.
So, rewire the motor for 240 per the manual. Connect the white and black wires in the cord to the flat blades on the 14-30P. connect the green wire to the u-shaped blade on the 14-30P. The L shaped blade will not be used and you won't connect anything to it.

As Tom said you should change the breaker in your panel for this circuit to a two pole 15 or 20 amp breaker.

[edited to add] If you bought a 14-30P with cord already attached, it will have four wires. You will only use the black, red, and green wires; the white wire should be capped.

[Jim Becker]

To use the four wire receptacle, put an appropriate matching plug on the saw's cord connecting the two hots and ground. There will be no connection for the neutral on the saw side. A four wire circuit with a 14-30 is dual voltage 240/120 capable. You only need the 240 accommodation for the saw.

[Tom Dixon]

To use the four wire receptacle, put an appropriate matching plug on the saw's cord connecting the two hots and ground. There will be no connection for the neutral on the saw side. A four wire circuit with a 14-30 is dual voltage 240/120 capable. You only need the 240 accommodation for the saw.

If you go this way you still need to swap out the 30 amp breaker to match the saw. Based on the Docs Paul posted above looks like that needs to be a 15 amp double pole. I still think a locking plug is a better way to go. L6-15R L6-15P

[Bill Dufour]

As others have said use green or bare for ground, white is not used. If white exists do not just cut it off but cut and wire nut it off. The dark wires are connected to hot.
Is this just a cord end you bought or is a molded plug and length of new cord?
If it is jut a cord end you ignore the neutral screw.
If it is a molded plug and cord you have to wire nut off the white wire.

House wiring is actually very easy:
green or bare is ground, white or gray is neutral, all other colors are hot.
that said light fixtures and switches can be odd.

Bill D.

[Terry Therneau]

Some devices have both 110 and 220 volt aspects, for example a clothes dryer might have a light (110) along with the dryer element (220). The 4 wire plus is meant to address that by having two hot, a neutral and a ground, hot+hot for 220, hot + neutral for 110. Your saw doesn't need the 110 part, so the neutral (normally white) can terminate at any convenient point. If you had a 4 wire plug and 4 wire connector to the saw, it would get capped at the saw's wiring box, for instance.

[Jim Becker]

If you go this way you still need to swap out the 30 amp breaker to match the saw. Based on the Docs Paul posted above looks like that needs to be a 15 amp double pole. I still think a locking plug is a better way to go. L6-15R L6-15P

The breaker protects the wire, not the saw. There's no need to replace the breaker with a smaller one. Since it's a four wire circuit, the L14 or other four wire design is required. Since it's "normal" intention is to be a dryer circuit, leaving it as-is (which is just fine) preserves that for future owners.

[Darcy Schaffer]

Thanks to everyone for the quick and very informative responses. This is exactly what I was hoping for when I asked the question.

I've been on the site for quite a while but am still amazed at the quality of information found here.

[Darcy Schaffer]

If you bought a 14-30P with cord already attached, it will have four wires. You will only use the black, red, and green wires; the white wire should be capped.

Thank you! This is exactly what I needed. I did purchase a 14-30P plug with cord so will attach it as you suggested. I'm looking forward to using 240v and freeing up a 110v for other uses.

[Darcy Schaffer]

If you bought a 14-30P with cord already attached, it will have four wires. You will only use the black, red, and green wires; the white wire should be capped.

Hmmm...sorry but one more clarification needed. You suggest I use black, red, and green wires from the cord but the manual shows black, white, and green. Do I just use the red wire from the new cord in place of the white one shown in the diagram?

[Paul F Franklin]

Yes, per the diagrams that Steve so helpfully posted, you would connect black to black, red from the cord to the white from the switch, and green to green, and cap off the white wire from the cord.
You should, actually, wrap a bit of black or red tape around the white wire from the switch since it is now a hot wire and not neutral. This convention tells some future person that the white wire is not a neutral. You don't need to cover the white wire, just one wrap of black tape near the end of the wire is good.

[Darcy Schaffer]

Yes, per the diagrams that Steve so helpfully posted...

Thank you again!

[Bill Dufour]

I use a black sharpy marker and then slip some dark color heat shrink over the wire. Any color is fine as long as it is not green or white. I would also stay away from brown or yellow.
Bill D.