110 or 220?

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On Thu, 21 Feb 2008 04:48:18 GMT, Robert Allison

The whole key to this is what the supply is like. If you have a good stiff 120V supply with a short cord, you likely would see zero difference between 120V and 240V wiring. Once the voltage gets to the motor the motor cannot tell whether it's 120V or 240V, anyway. The voltage goes through the same windings (just differently) Each winding sees exactly 120V regardless of how the motor is hooked up.
However, the wires outside the motor are all the difference. If your 120V supply is a long way from the panel and you have a long motor cord, and god forbid it's a 15A circuit, your saw is going to jump to life like a racehorse out of the gate when it's wired (and supplied) for 240V.
It is not, however, because there's something magic about 240V or the motor. It's about double the current draw at 120V and four X the percentage of voltage drop that makes the difference.
And there're no heat issues, no energy savings, no magic pill. Stiff supply, no difference. Long runs, 240V usually makes a difference.
--
LRod

Master Woodbutcher and seasoned termite
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Add the 220 and you will probably never have voltage drop problems using 220. Many stationary planers and larger band saws, jointers, etc run on 220.
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On Wed, 20 Feb 2008 07:12:30 -0800 (PST), Airedale

How many horsepower does the table saw generate? Another way of asking is how many amps does the table saw draw at 110 volts, both on start up and under load?
If you were looking at a 1.5 HP table saw, or the amps are at 15 or under, you'd probably be OK with a 110 volt circuit, 20 amp circuit breaker, 12 gauge wire.
At 2 HP or more, or over 15-18 amps current draw, you really are going to want a 220 volt circuit, as the alternative is a 30 amp 110 volt circuit and 10 gauge wire, which doesn't make a lot of sense to put in.
Regardless you want to dedicate this circuit to the table saw.
If you ever want a dust collector for your saw, or other heavy duty tools, the subpanel others have suggested is going to save a lot of money over time.
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"Airedale" wrote:

This question comes up at least every other week.
Yes, you need 240V in the shop if you are going to do any serious work involving stationary power tools.
To do the job so that you get the biggest bang for the buck, install a 2P-60A sub feeder in the house panel, a 12/24 ckt, 125 MLO sub panel with a 2P-60A main, in the garage and #4 feeder wire in a new conduit. (1-1/2" plastic will make pulling the wire a lot easier).
(Yes you can save a couple of $'s with #6AWG, but I like #4AWG, especially when you only do this job once)
Find an electrican who wants to pick up a few extra $'s and work with them.
You do the grunt work under their direction, they make the hook ups.
Have fun.
Lew
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Advantage of 220: Less voltage loss in the circuitry. Thus more of the power that are buying (at a not so cheap price these days) gets wasted heating the wiring.
Disadvantage of 220: Costs lots to install in old work. But only an electrician would know how much more (depends on whatever else needs to be done at \the very least..
Jim
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Tell you what: why don't you calculate exactly how much difference that makes, and get back to us with a monthly cost delta. Hint: not as much as you think.

Pfffffft. The additional labor to install a 240V circuit, as compared to a 120V circuit, is negligible. Certainly doesn't cost "lots".
--
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Doug Miller (alphageek at milmac dot com)
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wrote:

Once upon a time, I wanted to install an electric oven in my kitchen which needed a 60 amp circuit. The existing oven only needed a 40 amp circuit, and that was what was in the house. So, I called an electrcian to get an idea. He quoted a very high price because he would need to replace the wiring. It is the labor involved in old work that runs the cost up. The cost of the wiring, etc., is almost incidental. I am talking about making changes to an existing structure. It certainly would not cost me very much to install a 240v circuit in my garage because there is already a 240v line inside the wall. Jim
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So the electrician comes out and quotes me $780 to run the new line. I am blown away at how much it would cost for that.
Because we are planning on moving in about 5 years, I wasn't willing to put that much money into the place for something I won't be reaping the benefits of in the long run.
Instead I had him switch over an existing line in the garage from 15 Amps to 20 Amps. The only other thing that runs on that are a couple of shop lights. Those don't draw too much amperage so I figure I'll be fine.
Since the existing line was run with 14 gauge wire, they beefed it up to 12 gauge. That whole little fiasco cost me $275.
You guys have any similar experiences? I am left thinking to myself that I got into the wrong industry!
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Airedale wrote:

Around here the homeowner can get a permit to do electrical work as long as it's inspected by the power utility. (Once nice thing about this is that the inspector is then available for code interpretation questions.)
Shortly after buying my house I installed a new subpanel in the garage and added a whole bunch of outlets (120 and 240V, various amperages), overhead lighting circuits, unit heater circuit, etc.
If you have the skills to do it yourself, it's *much* cheaper.
Chris
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Airedale wrote:

OK, so to "beef up" the existing line from 15 to 20 amps, he had to pull wire. What he pulled was probably "12-2 plus ground" if it was nomex type. If it went in conduit, he just used the old wire to pull in the new, into the same conduit.
He could have pulled in 12-3 and given you a 240 volt, 20 ampere circuit just as easily, and you'd have double the capacity for something like 20% more wire cost and the cost of the other pole breaker.
Why the 60 ampere circuit was so much was really related to a single thing. To run a 60 ampere circuit, you need heavy guage wire (costs considerably more per foot) and it's a royal PITA to pull in the heavier wire, compared to 12 guage. If you are running in existing conduit, there wouldn't have been enough room inside the conduit to hold the wire (plus the air space required by code) for the heavy guage wire for a 60 ampere circuit. It's not the fact it was 240 volts, but it is directly related to the amount of current you are trying to carry.
Without knowing how far you were running from panel to outlet, it's hard to determine if you were being overcharged. On the other hand, if you ingore the wire cost, what's the hourly rate where you live for an electrician? I bet it was a large portion of the cost involved, particularly as you got the 120 volt circuit for only $275...
--Rick
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On Thu, 21 Feb 2008 08:51:35 -0800 (PST), Airedale

$780...Ouch! My house was setup for a 220v outlet for an electric stove. Since I have a gas stove and gas clothes dryer, I had a choice to take one of these for my shop 220v circuit. I decided to take the stove 220v and wired that into the subpanel in my shop. I left the 220v laundry alone because I thought electric clothes dryers are more popular than electric stoves. Plus a gas stove (unlike a clothes dryer) would be left with the new home owner. I paid an electrician $50 to inspect and test my wiring.
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Exactly so. It is the labor involved in old work. Whether it's 240V or 120V is almost irrelevant; it costs hardly any more to install 240V in old work than it does to install 120V in old work. The cost is not a "disadvantage of 240V" as you called it; the cost is a disadvantage of old work. That electrician would have charged you very nearly the same to install a 60A 120V circuit.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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On Wed, 20 Feb 2008 07:12:30 -0800 (PST), Airedale

I'm going to be a bit of a contrarian on the subpanel. Nothing against the idea, just might be overkill depending on your plans.
My 400 square foot shop started with a single 20 AMP 110 V circuit pulled from the main panel and a lighting circuit that came by extending an existing, underutilized, lighting circuit from the carport. For years this worked fine.
I then added several 220 tools and ran a second circuit from the main panel to handle 220.
I only run one tool at a time or occaisonally, one running on the 220 circuit and one on the 110 circuit. I've often worked with a friend and the single 110 circuit was able to run my RAS and Jointer, with the table saw running on the 220 circuit as we rapidly processsed a lot of lumber for glue up.
Never any tripping or voltage drop problems.
My advice, if you have even a remote plan to make the garage a real shop and are going to be drawing lots of power in the future, the the 60 amp minimum subpanel is probably a good idea. Particularly if you plan to be there for a while. If not, you may be just adding a lot of electricians cost.
Now, that said, I'm planning a shop expansion, doubling the size and connected load and will put in a 60 Amp subpanel. Primary reason is the addition of a dust collection system and having an air compressor on random start feeding shop air. But it took me 15 years to get to the point I need the additional power.
Look past your connected load to your diversity factor. Connected load is not important if very little is operating at any given time.
It may be that pulling the wire for the second circuit in the existing conduit is your most cost effective approach.
Frank
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I agree Frank. I operated most of my equipment on a 15 amp circuit for almost 20 years, I still do. I added 220 when I had to, my cabinet saw only runs on 220. Fortunately that enabled me to go with a honken band saw and a stationary planer. The Performax drum sander needs to be plugged into the single 20 amp circuit as it an the DC are too much for the 15 amp circuit. Typically I can run the DC, large router, radio, lighting, and fan on the 15 amp circuit, but shut a tool down quick if the compressor starts up. LOL
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Frank Boettcher wrote:

I'm a fan of the sub panel. It gives you the flexibiltiy you need without having to make long runs from the main panel (Of course, nobody's mentioned yet that the main may be nearly full already, so that means a suh-panel anyway if you want more than a single 240 volt circuit..)
In my shop, which is manned only by me, I've got the following on 240 volts: 3HP wood lathe, 3HP cabinet Saw, 5hp wide Belt sander, air compressor, 18" bandsaw, dust extractor and two different electric welders. Correct, I can't run them all at the same time, but to run the drum sander, I need to have the dust extractor running or I die from the dust, and the compressor has to be able to run periodically to keep the belt moving (it oscillates back and forth under air power. No air, and it won't even start...) There's a bunch of other 120 volt tools too, but most don't contribute heavily to the total running load of the shop.
As I'm not willing to run back and forth and turn the air compressor on and off, it's always enabled when I'm in the shop and could start at any time. (Gettin' lazy in my older age.) Anything that generates significant dust or shavings (Cabinet saw, Lathe, Belt Sander, Planer) also requires the dust extractor at the same time or I spend more time cleaning than working. If I'm putting a finish on a bowl on the lathe, I often spray lacquer, so the compressor runs fairly often while the lathe is running in this mode. Add a few normally forgotten loads and it's easy to add up to a sub-panel making sense, even in a much smaller shop.
My Shop is 28 x 32 feet (though half is taken up by "temporary storage" as we build our house) and has four 30 amp 240 volt circuits, 2ea 50 amp 240 volt circuits for the welders (opposide ends of the shop, it just worked out that way) and all of the 120 volt circuits are 20 amperes each, with most 120 volt circuits feeding only one or two outlets. Filled a 28 slot breaker panel. Some days, I could still use a few more outlets, but have some 10 guage extension cords for odd machine placement.
If you are really only going to run one thing at a time, and never plan on any expansion, you may be able to squeak by on only a few circuits, but having lived with inadequate capacity for over half of my life, it's just no longer worth it anymore to try to "get by". It's like some of the power tools. I "GOT BY" with an old Craftsman almost-contractor type saw with a 1.5 HP motor on it for years, but spent a bunch of wasted time waiting for it to recover or by sawing really slow in hard woods. Moved to a good 3HP 240V Cabinet saw and the difference is amazing. If I could only have done it years ago my frustration with table saws would have dropped a long time ago and I would have gotten more work done in the same time.... Seme thing with electrical service capacity. Just getting by with minimum was frustrating and wasted a lot of time that could have been put to productive work (or more recreation!)
--rick
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"thinks I can use the existing conduit to add in another line if it is just 110. "
It appears you are hesitant to do your own electric. But the cost differential (contractor vs self-install) will be significant for many folks - certainly for me!
However, if you already have a conduit line running 110 into the subject area and the electrician indicates he could add another circuit through that same conduit run (which involves using one or all of the existing wires in that conduit to pull a string through ther conduit and then tying that off to the new group of wires and pulling them back through.
So, if it were me, I'd look at the conduit run and see if I couldn't fit a sub-panel at the point it enters the subject space. (You can mount them recessed into or on the wall surface) and check the specs to see the largest gauge wire one might pull through the existing (I am assuming tubular) conduit run and the max amp that gauge wire would carry. If you can fit 10/3 you could do your 220VAC and if you can fit 8/3 even better - more amps.
You put a 15 Amp breaker in for the existing circuit and add breakers for the 220 for the saw and another breaker or two for additional tool circuits as suggested elsewhere in the thread.
If what your electrician saw was a straight run through an existing conduit from you main panel to your garage, its as if you have a small entension cord (in there) and need to replace it with a larger extension cord. How simple is that?
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