Using 220V/30Amp outlet to feed 110V/30amp power tools

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Old 02-20-18, 10:06 AM
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Using 220V/30Amp outlet to feed 110V/30amp power tools

Hello everyone,
My table saw requires 110V and 30 amp. I don't have a budget to add a new breaker so I am looking for a cheaper alternative. I have an existing 220/30amp outlet in the garage for electric dryer but I never use this outlet (I have a gas dryer). I also have a brand new voltage converter which can convert 100V to 220V and 220V to 110V. I greatly appreciate any advice you can provide. Of course, safety is my #1 concern so if there is no safe cheap alternative then I will beg my wife to hire a qualified electrician. Thank you much!
 
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Old 02-20-18, 10:27 AM
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If you have 10/3 wire running to the existing outlet, then I believe you can simply use one of the 120V legs and the neutral to get your required 120V/30A. Others with more knowledge on the subject will chime in shortly.
 
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Old 02-20-18, 11:01 AM
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1) If the dryer receptacle is 3-prong, you can rewire it as a 30A @ 120v circuit. This will involve a new receptacle, and moving some wires around in your panel.

2) If the dryer receptacle is 4-prong, you can create an adapter cable to go from the 4-prong to a 3-wire 30A @ 120 for your saw.

2a) If the dryer receptacle is 4-prong, you can alternately rewire it to a 30A 120v receptacle and rewire it in your panel.


What kind of plug does the table saw have?


We can certainly help with any option! Let us know what you have and we can help figure out your next steps.
 
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Old 02-20-18, 11:41 AM
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Hi Mossman,
Thank you so much for the reply. I don't know what kind of wiring going in to the outlet but the outlet is 3-prong type. How can I find out for sure what kind of wiring running to the existing outlet? Thank you.
 
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Old 02-20-18, 11:44 AM
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Hi Zorfdt,
Thank you so much for replying. The existing outlet is 3-prong type. If you show me what to do, I think I can work with the new receptacle but I am a little nervous working with the panel. You can tell, I am an absolute beginner with electrical. Thank you much!
 
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Old 02-20-18, 11:49 AM
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HI Zorfdt,
Sorry I did not answer your last question. I forgot what type of plug the saw is. I will call my wife to take a picture and I will get back to you ASAP.
 
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Old 02-20-18, 12:20 PM
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It is unusual for a table saw that is 120V to require 30A. Are you sure of this?
 
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Old 02-20-18, 12:29 PM
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Seems like a very high load for a 120 volt saw.
 
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Old 02-20-18, 12:42 PM
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Hi Pattenp,
I was surprise when I learned about the power requirement, too. It is Grizzly G1023S110 10" table saw, 2.0 Horse Power. I think with 110V and 15A, it should produce roughly 2 HP (I am guessing here, please correct me if I am wrong), but the saw manual specifically requires 30A and said that the saw will draw at least 25A. Thank you for replying.
 
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Old 02-20-18, 12:50 PM
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Doesn't that saw have a factory installed 120V 20A plug?

Edit: You are correct, it calls for a 110V 30A circuit using #10 wire.
You can make an adapter or change the outlet to a 120V 30A and cap off one hot leg.
 
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Old 02-20-18, 01:07 PM
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I believe you can simply use one of the 120V legs and the neutral to get your required 120V/30A.
Just a minor correction. There are no 120v legs. There are two 240 volt legs and a neutral. Your house is supplied with 240 volts. The 120v is derived from one leg of the 240v and the single neutral.

A 3-prong dryer receptacle usually doesn't have a ground and no ground means it can't be converted to 120v. Open it and if just red, black, white there is no wire (if #6 or smaller) that can be redesignated as ground. Code requires bare or factory green for ground.
 

Last edited by ray2047; 02-20-18 at 01:26 PM.
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Old 02-20-18, 01:30 PM
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Hi Pattenp,
Thank you so much for the advice. How do I make an adapter and how do I change the outlet to 110V/30A? Which of the two is more suitable for a beginner like me?
 
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Old 02-20-18, 01:33 PM
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Hi Ray2047, I will open it up and get back to you with the findings. Thank you much!
 
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Old 02-20-18, 02:33 PM
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Nominal voltages are 120 and 240.
how do I change the outlet to 110V/30A?
On a 3-slot you probably can't without technically violating code.
 
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Old 02-20-18, 02:41 PM
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Sorry I was misleading you by suggesting an adapter and somewhat on changing the outlet to a 120V 30A. If you are lucky and the wire supplying the dryer outlet is a cable such as NM or SE where one wire is black and one is white and one is bare you can change the white to be neutral by moving it from the breaker to the neutral bar leaving the black connected to one side of the two pole breaker or replace the double pole breaker with a single pole 30A., That way you can install a 5-30R outlet, which means the saw should have a 5-30P plug on it. The neutral goes to the "L" shape blade of the outlet or terminal "W".
 
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Old 02-20-18, 02:41 PM
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Just a minor correction. There are no 120v legs. There are two 240 volt legs and a neutral. Your house is supplied with 240 volts. The 120v is derived from one leg of the 240v and the single neutral.
I haven't thought of it that way, but I agree a home is provided with two hot legs, with a combined potential of 240V measured from one leg with respect to the other, and a center-tapped neutral. To get 120V, you use one hot leg and the neutral (as we said). I don't personally think of it as two 240V legs. To me, that would imply there is 240V from one leg to some reference and 240V on the other leg to some reference.
 
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