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Wiring Question

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  • Wiring Question

    I have an electrican scheduled to come by my house this week to take a look at my A/C and discuss adding some security lights. While he's there, I want to look at the possiblity of adding a couple of 20 amp 115 recepticles in my garage/workshop. There is a very good chance that I may have to add an additional box. If I do, I want to consider the possiblity of rewiring my TS2424 for 220 volts. I also have a 14" Jet bandsaw and 6" Delta jointer that can be rewired for 220, but the TS 2424 is used more than these. Any recommendations? What would be the advantages? Disadvantages? If this helps, I do cut some 8/4 hardwood and have had some problems doing that with the 2424.

  • #2
    Everything I read recommends the 220 for exactly the reason you mention... more HP.

    I am getting ready to run mine now (I will have a licensed adult do final hookups). IIRC, draw at 110V is 13 amps, at 220V is 6.5A (that's for 3612, but should be comparable). More power for less electricity, plus you aren't sharing a circuit with lights, vacs, and coffee makers.

    My electrician buddy says the mistake home shopworkers make is oversizing the circuit, on the ol' more has gotta be better philosophy. With a 20 amp service your saw has all the electrons it can use, but using a higher capacity circuit only increases the risk of fire. If things overload, the breaker is too far over normal operating range to trip in time.


    • #3
      Of course the electricity cost is the same whether it's 110V 10A, or 220V 5A, but the 220V seems to provide more instant starting and less chance of bogging things down due to torque problems. Half the amps could lead to an increase is motor life, and certainly I get zero light dimming and circuit drops compared to running a coupla high current machines on a 110V line.

      It's not an absolute must, but there are benefits to be gained. And if you have the guy there and are already rewiring, you should really take advantage, because later on should you need it, it's going to cost a great deal more


      [ 10-06-2003, 11:00 AM: Message edited by: Cutbuff ]


      • #4
        Thanks, that's what I wanted to know. I think I've been pushing the limits of my current ampage even though I've only had 4 or 5 thrown breakers and a couple of episodes of dimmed lights over the past couple of years. I'm going to look into getting a couple of 220s and a couple of dedicated 110s. My Rigid 1300 planer and air compressor both pull close to 15 amps. With dust collection and some things on the breakers from inside the house, I'm pretty much maxizing out my ampage.


        • #5
          Hi Guys,

          Power is Watt. Watt is Voltage multiply by Ampere. The Wattage of the motor does not change when the voltage is changed. Well, at least it tries to remain the same. What is improved at a higher voltage is the voltage drop in the circuit. Less voltage drop-better for the motor.

          In wiring your workshop, don't forget the "80% rule" requirement of the National Electrical Code.


          • #6


            • #7
              My imperfect understanding has it that while overall, watts is watts, the loss through house wiring is lower with 220v than with 110. That means startup loss is lower, motor is up to speed faster, and more electrical pennies go to actually get used (in my case, to increase scrap production).

              I don't think this would have a huge impact on anyone's electrical bill, but I was hoping it would theoretically be somewhat cheaper...


              • #8
                The total power is volts times amps, as already said. (If you get really technical, also times power factor, which is related to how the alternating waves of volts and amps are sometimes a little out of synch, but ignore that part for now.)

                Some of the total power goes to spinning the wheels and making noise, and some of the power goes to heating the motor and wires. The part that goes to heat is amps times amps (amps squared) times resistance. Resistance is very small (we trust), but look what happens...

                If you double the volts, you cut the amps in half. Same total power, same electric bill. But if you cut the amps in half, you cut the loss to heat in the motor and wiring in 1/4. Sure it is a small amount, but after you have used your saw a while, feel the motor, and ask if it would be better for the motor to only have had 1/4 as much heat. That is why 220 is good.

                Same is true for the heat in the wire, but if it feels warm, you have problems. Replace it with bigger wire immediately!

                Most houses are wired with number 14 (15 amp) or number 12 (20 amp) wire. Since you should never plan to use more than 80% of the capacity, anything that needs more than about 13-14 amps cannot get UL certification to plug in a home circuit. Which is why the heavier equipment (dust collectors, cabinet saws, air conditioners) require 220 volts.

                Hope this helps!


                • #9
                  Thanks, all of this has been helpful.


                  • #10
                    CharlieP is right on the money with his electrical knowledge- it's great to hear someone who really knows what they're talking about in this arena!

                    In regards to thinking about voltage and amperage and how they affect the motor, this water analogy may help. Voltage can be likened to water pressure and amperage to flow rate. You can imagine that you have a large, water wheel which is connected to a load, and is driven by a flow of water against the paddles. If the load on the water wheel increases suddenly (like cutting a hardwood), a greater water pressure (voltage) will keep the wheel spinning better than a greater flow rate (current) would. Hope this helps!

                    One of the really neat things about physics is that there are analogous relationships between electricity, fluid dynamics, and mechanics, so if you understand one of them well, the others can be understood by analogy. Yeah, I'm a bit of a geek, but I think that's really cool.


                    • #11
                      I'm a bit late reading this thread, and it seems now to have been established that the advantages of 220V are less heat generated in the motor (means longer life) and less voltage drop (which is a function of cord length, AWG and amps) (which also means longer life). 220V does not mean more power (except insofar as it avoids voltage drop).

                      The disadvantage of changing to 220V is that if you move your saw (pretty hard to do, given that mine weighs a couple of hundred pounds and won't fit through the bulkhead door without disassembly, but some folks might be in the habit of putting their saw in a pickup and taking it to a jobsite), you are out of luck unless they have a 220V outlet where you move it to.

                      What I wanted to comment on was the notion that there is anything wrong or dangerous in wiring a circuit for more amps than you intend to draw -- on the theory that the breaker would be too large to protect the motor. Wrong. The function of a circuit interruption device (breaker or fuse) is to protect the feed wires that are downstream of the device. The breaker is sized to the wire size. If a tool needs overcurrent protection because it might overload internally, it has to supply that protection itself.

                      The 110V outlets you are likely to find are configured for 15A and 20A plugs, and the 220V outlets will be sized for 20A. This means that they should be fed by appropriate wire size and protected by breakers sized for that wire. Regardless of the draw of the tools that might be powered from them.