230v is it a luxury or necessity?

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Forum topic by reggiek posted 06-16-2009 11:52 PM 1854 views 0 times favorited 7 replies Add to Favorites Watch
View reggiek's profile


2240 posts in 4610 days

06-16-2009 11:52 PM

Topic tags/keywords: tablesaw question voltage

I am currently wiring up my converted shop and wondering whether it is necessary/beneficial to hire a sparky to lay in 230v circuit or circuits? I am confident in my ability to handle the 115v circuits and load center…but not so much comfortable with higher voltages/phases.

I know about the differences in horsepower on tools using 230v. Like most folks I drool over a 3 or more horsepower table saw….but I am concerned about the practicalities.

Some of the issues I am concerned about is whether I would need to revamp my overall electrical to make room for a circuit or circuits (I believe that the property has a typical 100amp residential service). I have tried to research what the limits, as to circuits and circuit types, there are at this level without converting to a higher service?

There is one 220/230v circuit in use by an electrical dryer….I am researching whether that one be tapped or would it require different breakers and/or a new circuit in order to run an additional outlet with two or more items at a time.

Needless to say, I know there are lots of other folks that have hit this question….and am interested in ways/means used to solve it.

-- Woodworking.....My small slice of heaven!

7 replies so far

View Scott Bryan's profile

Scott Bryan

27249 posts in 5162 days

#1 posted 06-17-2009 12:02 AM

Reggie, if I am reading your query right you should look into the codes for your area. I can tell you that here in Kentucky codes mandate a dedicated circuit for each 230v tools or appliance. They cannot be run in sequence like you can for outlets on a 120 circuit.

-- Challenges are what make life interesting; overcoming them is what makes life meaningful- Joshua Marine

View gdickey76's profile


16 posts in 4628 days

#2 posted 06-17-2009 04:09 AM

A few points to think about are will you be moving your machines arround a lot, if so 110 makes it easy to plug in almost anywhere. The big advantage with higher voltage, is it draws lower amps so you can run smaller wire. Most motors over 1 hp should probably be run on 220, because they will draw less amps. If your running big motors on 110 you will probably more likely to be tripping breakers since most of them are rated for about 15 amps. I would recomend running all my stuff on 220 if your gonna start wiring from scratch. Other than that, Id just leave it at 110 for the flexibility of being able to plug it in wherever. Most all my machines are 220/ 3 phase anyway, so they have there own dedicated circuit, but only one or two is running at a time, plus a rotary phase converter. If your having trouble with constant breaker trips, I would consider installing a new heavier guage line at that time and make it either 110 with a bigger breaker, or just wire it for 220.
I would run a seperate line from the dryer, as you dont want to be doing laundry and running your saw and have everything quit. Im sure you know, but just always remember, DONT replace a breaker with one of a higher amperage, as the breaker is there to protect the WIRE not whats plugged in. Thats how fires are started. Motor overload protection should be on your machines too.
Hope this helps some.


View reggiek's profile


2240 posts in 4610 days

#3 posted 06-17-2009 07:30 PM

Great info, thank you for your insights. Indeed wire size is a consideration, I usually lean towards the largest (8-12 guage) I can work with …and even after that I still would install a breaker that would not allow the load to go near maximum. Being a contractor myself, I am always aware of code requirements…but in the electrical area I am not that proficient and I usually rely on an electrician to insure that the work is safe and correct.

I am leaning towards putting 2 circuits of 220 out there as mostly I will need this to run a higher horsepower cabinet style table saw instead of my contractors version and a decent joiner and thickness planer.

Not that I am having problems with my Bosh 4000, but it would be much more efficient and convenient to have a little more horsepower…and be able to cut wider dado’s. The arbor on my Bosch will only allow a stacked set to 5/16ths or so (I am sure there are other kits that may do a little better…but I would be concerned with the load on the motor)...Th short arbor means multiple passes for the majority of the dado cuts I make. I would also like a bit more precision in the fence and miter slots.

Also, another desire is to put a decent joiner and thickness planer in there, and I just don’t see any in the 115/120v category that would handle alot of the demand I would like to put on them….for now I have to use a friend of mine’s tools to straighten out the slop so that I can work with square material. I am sure he would appreciate this.

-- Woodworking.....My small slice of heaven!

View gdickey76's profile


16 posts in 4628 days

#4 posted 06-18-2009 04:23 AM

Well I agree with you there. If you are moving up to a larger more powerful saw and a planer that not a benchtop machine, Id go with 220, as you will have more machinery options. If your getting an 8” or larger jointer, Id go with 220 as well. All my machines that are 220v/ 3phase come off one large circuit since its only me and sometimes my bro working in there. So Ill never have more than 2 big machines running at the same time. I have 2 other 220 volt outlets, one for the radial arm saw, and one for my future dust collector someday. I guess if you are wiring up the walls anyway, it would be great to put in 220. It wont cost you much now compared to adding lines after the walls are covered.


View sikrap's profile


1121 posts in 4699 days

#5 posted 06-18-2009 04:48 AM

I am also setting up a shop and recently asked pretty much the same question. It was suggested to me that I run 220 for the TS and DC at a minimum. My house has a 100 amp service and my electrician is running a 100 amp sub-panel to the garage (new shop) and is going to put in 3 220 circuits and 4 or 5 120 circuits. Another point that seems to keep getting raised is that by wiring your big tools for 220, you can use thinner (less expensive wire). Hope this helps and Good Luck!!!

-- Dave, Colonie, NY

View PatentNonsense's profile


28 posts in 4706 days

#6 posted 06-19-2009 08:06 AM

It’s easy to tell what service you have already – just go look at your biggest circuit breaker (probably next to the meter) – it will have a number on it.

To me the 220V (aka 240V) is a very easy choice, to give you at least the possibility of running machines over one HP. There’s a reason why electric dryers, stoves, ovens and central AC units use it, so why not give your workshop some room to grow? Also, your wife and neighbors will be happier if their lights don’t dim when you turn on your tablesaw!

Important: when you wire 220V you HAVE to connect all three wires all the way. You can find books about electrical wiring in the big hardware stores, and they’ll tell you why.

A British engineer once commented, on the choice of 120V versus 240V, that it’s a question of whether fire or electrocution is the worse danger; for woodworking, you can keep toddlers out of your shop, but not sawdust.

You can indeed use plugs and outlets for 220V, especially if you stick to the very common sizes: I believe that a standard 30A dryer cord will let you run a 5 HP motor (but check the motor’s rating plate to be sure).

I’ve fudged up a quick spreadsheet to estimate what motor HP you can run on what size circuit. (That’s a little more complicated than it looks, because some of the current that flows is out of phase with the voltage.) PM or email me if you want a copy (remembering that I’m not an electrician and am not promising that these numbers are correct.

If money is tight, and you’re going to hire an electrician for a job like this, you might consider asking him to specify the system, let you do as much of the dirty work as possible, and then do final connections and checking. (Some of the work is just dirty and boring, e.g. crawling through attics or under the house to run and staple cable.) If you don’t have to have a permit, and don’t have to have your electrician sign off on the job, it will be less expensive. That way you’re more likely to get a working licensed electrician who really knows his/her stuff, for a few hours of moonlighting.

My dream shop will have 240V and 480V three-phase – some amazing bargains come up in used machinery and three-phase motors. (We can start a new thread, rather than hijack this one, if anyone wants to talk about three-phase.)

I also like armored cable (BX or such) or rigid metal conduit – squirrels floss their teeth with Romex.

View WibblyPig's profile


172 posts in 4614 days

#7 posted 06-19-2009 04:20 PM

It’s always nice to have 220 for something that may occur in the future. 7 years ago, I put two 220 circuits in the shop even though I only need one. Last winter, the blower on the furnace went out so we had to get a new one. 2 weeks ago, the compressor on the heat pump blew up so we had to replace everything. I pulled the blower unit (220) out of the old furnace, will add a few filters and turn the whole thing into an air cleaner. Now I can use that second 220 circuit.

Who’s to say you won’t happen upon a $100 Unisaw or 5hp planer and end up needing the juice? Wiring it isn’t much different than a regular circuit. You’re still pulling 3 wires – it’s just that 2 are hot and one’s a ground.

-- Steve, Webster Groves, MO "A society grows great when old men plant trees whose shade they know they shall never sit in."

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