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wiring for 220v table saw

rholland54's picture

I am finally getting power to my shop and want to prewire an outlet for a future Grizzley 220V 3HP table saw.   Specs. on saw indicate 18 amps.  What size wire do I need to run from the panel ?  I figured 10/3.  I want to get this in place before I do any sheetrock work.  Thanks.


Robert

mudmanmike's picture

(post #97463, reply #1 of 18)

Robert,


12/2 will carry up to 20 Amps, so that would be plenty. Obviously 10/2 allows for upgrading  to a 5 horse! or to run a dust collector off the same circuit. The consensus around here seems to be to over wire everything. Nothing wrong with that, but no real advantage either if the circuit is dedicated for the saw. If the run is long, more than 50 feet from the panel you MAY need 10 ga. There are charts that show this wherever you go to buy the wire. Also remember that for 220 you dont need 3 conductors, the "common" is not used. So you can use 2 conductor wire, just be sure to mark the white wire with black or red tape to indicate it is hot. Use three conductor if you also want 110 availible in the box. I ran about 15 feet of 12/2 to my 3 horse Unisaw and there is NO flickering of lights at all on startup.


Enjoy the new saw!


Mike


please excuse my spelling.
please excuse my spelling.
BArnold's picture

(post #97463, reply #3 of 18)

"Also remember that for 220 you dont need 3 conductors, the "common" is not used. So you can use 2 conductor wire,..."


This might be OK if you throw safety out the door.  What about the GROUND connection?


Technically, a 220v motor will operate as you wired it.  Without the ground installed, not only is it unsafe, it is not to code.  All equipment must be connected in a manner that brings all grounds together to reduce the possibility of electrical shock.


Regards,



Bill Arnold - Custom Woodcrafting


Food for Thought: The Ark was built by amateurs; the Titanic by professionals.



Edited 9/27/2004 4:14 pm ET by BArnold

Bill Arnold


Food for Thought: The Ark was built by amateurs; the Titanic by professionals.

JohnWW's picture

(post #97463, reply #5 of 18)

Bill,


The common is not the same as the ground, the ground would still be included, it wasn't mentioned because it is presumed that a ground is always installed.  The wire serving as a ground is not referred to as a conductor so suggesting a two conductor cable was the correct terminology, a two conductor cable would in fact have a third wire to provide a ground. 


My preference is to run the common even if it isn't needed for the tool the circuit is being created for.  At some future point someone may want to hook up a tool that needs both 110 and 220 volt circuits and it is a lot easier to just change the plug than to have to go back and install a new cable.  Tools with electronic controls in addition to motors sometimes need both, although this is still rare with woodworking tools.


John W.

John White Shop Manager for FWW Magazine, 1998 to 2007

BArnold's picture

(post #97463, reply #6 of 18)

John,


You can 'pretty-up' your comments any way you wish, but when someone requests information the least you can do is be ACCURATE!  There is a BIG difference between 12/2 and 12/2 w/GROUND; the latter being a THREE conductor wire, NOT 2 conductor as you indicated!!!


If you are going to give advice, please do it in a way that won't get somebody KILLED!!!!!!!!!!


Warm Regards,


Bill Arnold - Custom Woodcrafting


Food for Thought: The Ark was built by amateurs; the Titanic by professionals.


Bill Arnold


Food for Thought: The Ark was built by amateurs; the Titanic by professionals.

JohnWW's picture

(post #97463, reply #8 of 18)

Mr Arnold,


YES, the job would need two or three conductors, AND a ground.


The original advice, given by Mike and further discussed by myself, only concerned the number of conductors that would be needed for the application.  Neither the original posting or my comments said anything at all about deleting the ground wire.  As I tried to explain in my first posting, a ground wire isn't called a conductor because it doesn't ordinarily conduct power


If you ordered a three conductor Romex type of cable, as you seem to think is proper, it would have three current conducting wires in it, typically coded red, white, and black, it still would not contain a ground wire.  For that you would order a cable with three conductors and a ground, that cable would contain four wires, only three of which would be called conductors.  


Mike and I only commented on the number of conductors, we never talked about the ground and we never implied that it should be deleted.  Skipping the ground is something you mistakenly read into our comments because you didn't understand the terminology, a misunderstanding I tried to correct in my first posting. 


The work would also need to conform to dozens of other electrical code requirements that we also didn't talk about.  Nobody meant to imply the other requirements, including grounding, should be ignored simply because we didn't talk about them.


John W.


Edited 9/27/2004 10:29 pm ET by JohnW


Edited 9/27/2004 10:30 pm ET by JohnW

John White Shop Manager for FWW Magazine, 1998 to 2007

Jellyrug's picture

(post #97463, reply #11 of 18)

At first, did not want to jump into this discussion, but could not resist the temptation. So, decided to share my wealth of knowledge, to clear up all this confusion......


"Potential difference" has two meanings:


1.) 1 volt is the difference of potential between two points of a conducting wire, carrying a current of 1 ampere, when the power dissipated between these points is equal to 1 watt.


2.) The second definition of "Potential difference" is the difference of opinion, between a population of woodworkers, where there will always be high Potential, for differing opinions about the electrical sciences. This difference normally burns several watts of wasted energy.


Let's try and explain "Conductor", also with two definitions:


1.) The first is a fellow, who rides in a bus in England and stamps holes in your ticket. He is referred to as a "Conductor"


2.) The second is something, (normally a wire) which offers sufficient low resistance to conduct electrical current. One ohm is the resistance  between two points of a conductor when a constant difference of potential of 1 V, applied between these two points, produces in this conductor a current of 1 A, the conductor not being a source of any electromotive force.


The second point above, brings me to the last argument, or debate, about this electrical subject.


If you use a ground wire, which is not a conductor, and then you experience an earth, or ground fault, you as the human being will become the conductor. When this happens, two things can happen. 1st, you can end up standing in a puddle, with a warm comfortable feeling left in your pants. 2nd, your heart may just decide to give up and actually stop.


The next subject I wish to talk about is the capacitance of the human body, compared to an electrical wire, but more about that later.


Benjamin Franklin Jr.


Edited 9/28/2004 12:31 am ET by Jellyrug

BArnold's picture

(post #97463, reply #12 of 18)

"Neither the original posting or my comments said anything at all about deleting the ground wire."


Unfortunately, the original posts said nothing about a ground wire at all.  If one goes to the Leviton site referenced in another post, one will find a diagram for connecting two-wire circuits (no ground).  If one were to follow the original advice, connect the tool via two-wire cable and follow the diagram, one could get killed.  When giving advice to anyone, we must be careful to include all pertinent information with terminology such as 10/2 w/ground, not simply state 'all you need is two conductors'.


As to the terminology regarding the use of the word 'conductor', one can assume that if the ground 'wire' doesn't 'conduct' the potential of the ground buss to the attached tool then that tool is not safe.  Also, one cannot assume that the potential of the shop ground buss is truly at 'earth ground'.  I've worked in communication facilities where we had to install 'halo' ground busses and tie them to a grounding grid buried in the soil outside the building to achieve a true earth ground at all points for safety.


Regards,



Bill Arnold - Custom Woodcrafting


Food for Thought: The Ark was built by amateurs; the Titanic by professionals.



Edited 9/28/2004 7:15 am ET by BArnold

Bill Arnold


Food for Thought: The Ark was built by amateurs; the Titanic by professionals.

BArnold's picture

(post #97463, reply #13 of 18)

More on the term 'conductor':


Check this link: http://www.amercable.com/glossary.asp


Exerpts from the link:


Ground - A conducting connection, intentional or accidental, between an electric circuit or equipment and the earth or some conducting body serving in place of the earth.


Grounding Conductor - A conductor used to connect equipment or the grounded circuit of a wiring system to a grounding electrode or electrodes; usually colored green.


Exerpts from: http://www.multicable.com/glossaryg.asp


Conductor. An uninsulated wire suitable for carrying electrical current.


Ground. A conducting connection between an electrical circuit and the earth or other large conducting body to serve as an earth thus making a complete electrical circuit.


Regards,


Bill Arnold - Custom Woodcrafting


Food for Thought: The Ark was built by amateurs; the Titanic by professionals.


Bill Arnold


Food for Thought: The Ark was built by amateurs; the Titanic by professionals.

TKanzler's picture

(post #97463, reply #14 of 18)

If it matters to anyone, the NEC is filled with references to "grounding conductor" (ground wire or other equipment or building ground component), "grounded conductor" (the neutral in single-phase systems, but present in loads of three-phase systems also), "current-carrying conductor" (which may or may not be grounded, but carries current in normal use, i.e. hots and neutrals, but not "grounding conductors"), along with "equipment bonding jumpers" (NEC Art. 90 definition "The connection between two or more portions of the equipment grounding conductor."), and so on.  "Grounding conductors" only carry fault current, generally, and need to carry enough current long enough to trip the overcurrent, short-circuit, or ground-fault (they're not always the same thing) protection device and clear the fault. 


Edit: And to confuse things further, non-metallic building wire (Romex) labelled 12/2/G has two current-carrying conductors and a bare grounding conductor, but you would need flexible cord marked 12/3, such as SO or SJ, to do the same thing, since all conductors are insulated (green insulated grounding conductor, for cable you can buy in the big boxes, but there are jillions of color schemes available) and are therefore counted in the designation.  There generally is no bare conductor in flexible cord. 



Be seeing you...


Edited 9/28/2004 9:09 am ET by Tom Kanzler

Be seeing you...

DJK's picture

(post #97463, reply #15 of 18)

Good GOD, these electrical posts are great. All this knit picking. When in school it was 2 wire with ground, 3 wire with ground and sooo on. I would run a #10-3 wire with ground so there is a nuetral if you need it later on for a couple of 115 volt runs.

DJK

MichaelPB's picture

(post #97463, reply #16 of 18)

My gosh, you are ALL neglecting safety and should be banned from the site.  None of you mentioned turning off the power first, or not standing in a pool of water or never lick your fingers and stick them into the outlet to test for hot...


Let's give it a rest and act like adults and have an actual discussion about the subject...

BArnold's picture

(post #97463, reply #17 of 18)

"Let's give it a rest and act like adults and have an actual discussion about the subject..."


Whatever your reason for directing this comment to me, I can only say that I am concerned about the type of advice I read in some of the posts on the forums.  I provided references to back up my concern about certain terminology.  If this, to you, makes me appear less than adult, then please explain.


Regards,


Bill Arnold - Custom Woodcrafting


Food for Thought: The Ark was built by amateurs; the Titanic by professionals.


Bill Arnold


Food for Thought: The Ark was built by amateurs; the Titanic by professionals.

MichaelPB's picture

(post #97463, reply #18 of 18)

Bill,


I said "adults" as in plural which means I didn't single you out.  Sorry if you thought I did. 

migraine's picture

(post #97463, reply #7 of 18)

"Also remember that for 220 you dont need 3 conductors, the "common" is not used. So you can use 2 conductor wire,..."


Scary when you read this isn't it...


Hopefiully he ment 2 conductor with ground wire(3 wire)

bones's picture

(post #97463, reply #2 of 18)

I have the 1023 and 10/3 will be fine, but I would up the breaker to 30A. I had an electrician wire my outlet, and he recommended not going over 70% utilization on the amp rating as a general rule.  Just remember, if you up the breaker to 30A, you need to up the plug to a 30A plug as well. Running a 20A plug on a 30A breaker could become dangerous. I have a good article on 220 that is about 2megs that goes into great detail. Drop me an E-mail if you want it.    I have a 30A breaker using a L630 plug.  Enjoy the new saw, I love mine.


 


 


http://forums.taunton.com/tp-knots/messages?msg=19264.4

...For that old machine lovers:  http://vintagemachinery.org/home.aspx

hammer1's picture

(post #97463, reply #4 of 18)

Run a 30 amp just in case you get a planer or want to run a DC on the same line. Make sure you use appropriate receptacles and plugs.

Beat it to fit / Paint it to match

Beat it to fit / Paint it to match

bones's picture

(post #97463, reply #9 of 18)

You have had a lot of info threw at you. If you are not comfortable wiring a 220v circuit, call an electrician! Although I have wired previous shops with 220, I hired an electrician because of time and I decided to go with EMT because my garage is finished.  My electrician ran (through EMT) two stranded copper 10awg (hots), and a 10awg stranded copper for a ground to my service panel. This is hooked to a L630 receptacle. The hots connect 1 each to a pole on a 30A breaker. The third conductor connects to the ground buss in my service panel. Here is a pretty good link from levaton's site (the mfg of my receptacle). Again, if in doubt call an electrician.


http://www.leviton.com/sections/techsupp/diagrams2.htm

...For that old machine lovers:  http://vintagemachinery.org/home.aspx

rholland54's picture

(post #97463, reply #10 of 18)

Thanks for the reply,  I  think I will use 10 ga. w/ ground,  from panel to outlet will be about 35 ft.    I did have an electrician run the new line from my house and install a 100 amp. subpanel.  wall and ceiling is still open so I want to run all the circuits that I think I will ever need.  Plan to sheetrock the whole shop, but that will probably take another year.  Once I have some lights on I will not want to take the time for that work.   


Robert