110 or 220

[John Bailey]

All the machines I'm looking at for my new shop are either 220 or 110/220. The DC and planer will definitely be 220, but the others can be either. It seems as though the 110/220 machines are easily switched. My question is, should I have most of my outlets be 220 (this is a new shop yet to be wired)? What are the advantages and disadvantages of 110 or 220.

Thanks, John

[Joe Mioux]

John:

Every electrician that I have dealt with always says when you have choice wire the motor for 220.

They say 220 v is easier on the motor.

So with that in mind and if it were my shop I would have atleast 4 or 5, 220 outlets, DC, TS, Planer, BS, and one extra.

Joe

[Roy Wall]

220 draws about half the amps compared to a 110 v motor.

110 machines are generally "lighter" duty and cheaper; plus "plug n play"......so easy to get rolling without electrical work. That is the beauty of 110v.

However, once the 220 is in.....it is just as easy.

I just added a 50 amp sub panel to my garage with 3 220 lines - I'm happy!!

[John Miliunas]

Yup, another vote for 220! The initial expense won't be that much more and you immediately give yourself a wider choice of future tools. Go for it!

[Jim Becker]

220 draws about half the amps compared to a 110 v motor.

The 120v/240v switchable motor draws the same agregate amperage (current) as the 120v motor...it's just split between two power legs and sets of windings. In all but a very few cases of "special" motors, the horsepower is the same, however, with either voltage setting.

Personally, I prefer to run stationary tools on 240v when I can--it was a real choice for many things I used to use, such as the Jet jointer and Jet bandsaw, but most of my prime machines now only accept 240v anyway. When you go above the 1.5hp motors, that's what it required if want to have reasonable wiring.

[Richard Wolf]

I have always dwelled on this myself and have never really got a satisfactory answer. We have alot of electrial experts on this site and may prove me wrong but here goes what I know. For machines in the size that you are talking about, 110 or 220, ;
1) 220 is not cheaper to run.
2) 220 is not more powerful.
3) 220 does not draw less amps.
4) 110 may run a little bit hotter if you run your machine continuesly.
5) 110 may dim lights in your house if the panel is small to begin with.
Nobody has ever told me of a real advantage to run a given machine at 220 instead of 110.
I could be wrong, I'm sure someone will point that out.

Richard

[Roy Wall]

Guys,

Why does a motor say.........for example.........

18 amps @ 110v or 11 amps @ 220............???

This makes sense that there's less resistance with 220...hence; less amp draw...

Richard - I agree 220 costs more to run!

[Jim Becker]

Richard - I agree 220 costs more to run!

Only in that the initial wiring might cost you more because the breaker, plug and recepticals cost a little more. A switchable motor that draws 15 amps at 120v and a draws 7.5 amps at 240v consume the same amount of electricity. (15 x 120 = 7.5 x 240) In your example, that 240v setting for that particular motor draws more than half of the 120v amperage...likely because it's been specially wired to take more advantage of the 240v setting in the realm of produced power. Delta used a motor like that on one of their contractors' style saws...1.5hp on 120v and 2hp on 240v...all because of the way the windings were configured. Not all switchable motors are that way...many are "even Steven" when you switch.

[Randy Meijer]

As I understand it your 220 motors will run cooler because of the lower amperage in the windings. A very basic rule of electrical equipment is less heat, longer life. All other things being equal, your 220 motors should last much longer than 110 motors!!

[Bill Neely]

I'd love to draw a picture here but I'm not up to it. There is no more current running through a motor connected 120V than one connected 240V. The windings are connected parallel for the low voltage - meaning each winding carries, for discussion purposes, 10 amps, they are connected together at the ends so only the wire bringing the power in actually sees more current. The 240V motor has the windings connected end to end (series) and each winding still carries 10 amps. Same amount of power consumed, same amount of heat.

Think of a 240V 200 watt light bulb - then a pair of 120V 100W light bulbs. Same amount of total power consumed.

[Rick Christopherson]

These are random thoughts not directed at any particular posting here. I can easily say this because the same misinformation is invariably repeated every time this topic comes up. (I will address the original poster's questions at the end of this.)

When I wrote Electricity in the Woodshop some 8 years ago, my motivation was exclusively to address this issue of rewiring 120/240 volt motors. I just ended up taking the article further than originally planned.
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It is unequivocally false that a motor will run cooler at 240 volts. The internal windings of the motor are still receiving 120 volts regardless how the external wires are configured. The current through each winding is exactly the same at either voltage.
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I spoke with Delta at the AWFS trade show in Las Vegas last month, specifically about their mythical motor that had a higher rated horsepower at 240 volts. They acknowledged that there was a mistake in the nameplate rating, which has since been corrected. You won't find this mis-rating on any of their new saws.
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This is a specific statement: Roy, I have yet to see a motor with that type of rating, with the exception of the mistakenly rated Delta motor.
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There is absolutely no difference in cost between running 120 volts versus 240 volts. Your electric company does not give anything away for free. The meter outside the house reads the total watts, which is independent of voltage.
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The motor does not know whether it is on 120 or 240 volts. The windings inside see the same voltage either way. In the 120 volt configuration, they are in parallel. In the 240 volt configuration, they are in series. It is not easier on the motor.
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The ONLY reason for changing a motor over to 240 volts is if the wiring in the shop is below code and cannot handle the current at the lower voltage.

When wiring a new shop, you should always be using 20 amp circuits for all outlets. There is not a single 120/240 volt motor on the market that will starve for power on a 20 amp, 120 volt circuit. 12 gauge wire requires a 20 amp circuit breaker, but the wire itself is rated for 25 amps. There is a built-in margin.
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As for the original poster's questions: If the tool is portable or semi-portable, then you should stick to 120 volts for versatility. If you move the tool, you can always find a 120 volt outlet, but 240 volt outlets are not always where you need them.

If the tool is non-portable and you know that you will never rearrange your shop (or move to a new location) then you could go either way. If you go with 240 volt tools, don't make the common mistake of oversizing the circuit, as this completely defeats the whole concept. There is not a single 120/240 volt tool that requires a 20 amp or larger circuit at 240 volts!

It drives me nuts to hear people saying they are going to rewire their motors, and then install them on 30 amp circuits. If you are going to go through the hassle of pulling #10 wire, you may as well stick to 120 volts, because it is overkill as it is. (#10 wire really sucks to work with.)

The only time you need #10 (30 amp) wire on a 240 volt circuit is for a "true" 5-hp motor.

A 3-horsepower Unisaw/PM66 will operate on a 20 amp circuit.

ALL (no exceptions) 120/240 volt tools will operate on a 15 amp (14 gauge) circuit at 240 volts with power to spare. As a matter of fact, two motors will fit on a single 15 amp circuit.
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If you want to be proactive without committing to 240 volts, then have several 1-or-2 outlet circuits pulled with 20 amp (12 gauge) wire at strategic locations. If you change your mind, these circuits can be converted to 240 volts by swapping the circuit breakers without having to pull new wire. In the mean time, they are fully functional at 120 volts.

[Rick Christopherson]

I'd love to draw a picture here but I'm not up to it. ....

Bill, you were writing your reply at the same time I was writing mine, but you finished sooner. I believe the picture you wanted to draw is shown in my posting. (I drew it 8 years ago.)

[Bill Neely]

That's exactly what I was picturing and a better explaination. Thanks.

[Bill Lewis]

If you want to be proactive without committing to 240 volts, then have several 1-or-2 outlet circuits pulled with 20 amp (12 gauge) wire at strategic locations. If you change your mind, these circuits can be converted to 240 volts by swapping the circuit breakers without having to pull new wire. In the mean time, they are fully functional at 120 volts.

This is exactly what I did with my shop. I made dedicated 20A 12/2 wire, circuits for the compressor, table saw, and dust collector. I wired the circuit for the contractors saw I had to be 120V20A initially. When I upgraded to the unisaw, I just changed the breaker and outlet to be compatable with 240V/20A. The reality is that even this is probably overkill. None of the motors have amperage ratings higher than 15A, so technically I could run them on 14/2, 15A circuits. Bigger gage wire will run cooler (note, I said the wire, not the motor will run cooler), and reduce voltage drop. My circuit runs are so short that drop is negligible.

I think this also begs the question, "Why are tools prewired for 240V?" I'd have to guess that one reason might be to allow them to run safely on a converted "house circuit".

BTW great response Rick, Richard, Jim and others. This debate (and the one on HP ratings for shop vacs) has been raging for as long as I can remember and it still comes up. I'll admit there was a time I didn't know the why either, and I can remember back around 1980 when it was first explained to me. I understood it, yet there was still some mystery surrounding it.

[Tom Jones III]

Amen to what Rick said. The only thing I have to add, I use 240 in my shop to get enough amperage to run tools simultaneously. Frequently friends will be over to help or work on their own projects and I often find the 3 HP TS and the 13" planer running at the same time. If these shared a single 20 amp 120 V line, then we would blow the circuit. The alternative is to run multiple 120 V circuits.

In fact, in my shop I've got white sockets that are 120V and used for the radio, fan, plug in lights, battery charger, etc. There are also 20A 120V grey sockets that are used for mobile tools and smaller stationary tools (MS, scroll saw, biscuit joiner, etc.) Then I have a big 240V that runs the jointer, planer and TS. There is a separate 240V circuit that runs the dust gorilla and the A/C. The overhead shop lights are on their own dedicated 120V circuit.