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question about 240V outlet

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  • #16
    Originally posted by Polar Sparky 1224
    I have been shocked a few times but never with more than a few amps.
    It takes less than an amp to kill you. In other words, playing around with an outlet is just as dangerous as a panel.

    Comment


    • #17
      Originally posted by MudIsFun
      I think the point he is missing is that the breaker for the drier is 30 amps. His saw is designed to pull several amps less and be on a circuit that for arguments sake is 15 amps. If the saw malfunctions or there is a surge his breaker should trip at 15 amps however he will be plugging into a 30 amp breaker so it wont trip until that 30 amps is exceeded which as far as I am concerned is BAD. At the best he fries his nice new saw, at worse he can be injured/killed or cause a fire.

      Call an electriction... They know how to do this correctly. And no, I am one.
      Kevin
      A circuit breaker's job is to protect the wiring, not the appliance. If you want to protect a motor than the correct way is to install some form of overload cutout on the appliance. A standard household circuit breaker is not designed for motor characteristics.

      Comment


      • #18
        That was my point to begin with... the saw's motor has it's own overload protection!

        After the initial posts, I checked an old code book and saw where it specifies a dedicated circuit for a laundry room (if I understood it correctly). However, my initial reasoning was to answer the original question about the possibilities of running a breakout from the 30 amp line, because of the cost and lack of additional capacity on the existing load panel. My answer was "Yes, unless there was some code against it" (which apparently there is).

        However, from a capacity and demand point of view, the saw would be okay, because it has it's own overload protection and that was all that was required at one time. However, I don't know if the code requirements have changed. So, given the original scenario, the saw could be safely run, but NOT at the same time as the clothes dryer. It really wouldn't be any different than running a line to your saw and also trying to run your compressor or dust collection system off the same circuit... you'd run the possibility of tripping the breaker.

        The argument made that the 13 amp saw motor would be in jeopardy if plugged into a 30 amp line, really doesn't make sense to me. Certainly there is no pronounced warnings against plugging your 3-amp vacuum cleaner into the fairly standard 15 or 20 amp circuit. The motor will simply draw what it needs. Am I wrong in this presumption?

        Now the question I have is: If there isn't additional capacity in the main circuit breaker panel to run a separate line to the saw and a line needs to be "dedicated" to the dryer... can the existing dryer line be run to a small circuit breaker box (instead of the dryer) and then, branch out to serve the saw and the dryer separately. Each of these would be protected by their own, dedicated, circuit. The end result being that you still have the one 30 amp line coming from the main panel to a small circuit breaker box located in the utility area, and from there, you'd have a "dedicated line" to the dryer and a second "dedicated line" to the saw. Wouldn't this satisfy any code requirement for a dedicated line? If so, then that would relieve the need to upgrade the existing main load center just so you can run another line out to the saw.

        Basically, I see this as no different than what I have have requested with my newly purchased home. The electrician has just upgraded the service from 100 to 200 amp. The next step will be to have the electrician install a 50 or 60 amp breaker in the main panel and run a line to my garage where a second panel will branch the load into separate circuits for lights and tools. I'm now waiting for his estimate to do that, but he certainly didn't raise any concerns when I outlined the project to him.

        Thanks,

        CWS

        Comment


        • #19
          " A circuit breaker's job is to protect the wiring, not the appliance. "

          I would add; "or people" , to the above after appliance.

          Also, is not the overload protection on the motor a thermal overload meant only to protect the motor from overheating NOT an overcurrent protective device (which could eventually cause overheating, and hence a thermal trip) and as such the thermal overload can not be used in place of a circuit breaker?
          ---------------
          Light is faster than sound. That's why some people seem really bright until you hear them speak.
          ---------------
          “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
          ---------
          "Its a table saw.... Do you know where your fingers are?"
          ---------
          sigpic http://www.helmetstohardhats.com/

          Comment


          • #20
            Originally posted by Bob D.
            " Also, is not the overload protection on the motor a thermal overload meant only to protect the motor from overheating NOT an overcurrent protective device (which could eventually cause overheating, and hence a thermal trip) and as such the thermal overload can not be used in place of a circuit breaker?
            You still need a circuit breaker regardless. What I meant was that the best way of protecting a motor is with an adjustable overload as commonly used with 3 phase motor starters. A bit of an overkill for a 220V saw.

            Being in Australia I don't know your code there, but would a changeover switch so you can only use the saw or the dryer but not both at the same time still satisfy the code requirement for a dedicated circuit to the dryer?

            Comment


            • #21
              Originally posted by CWSmith
              The argument made that the 13 amp saw motor would be in jeopardy if plugged into a 30 amp line, really doesn't make sense to me. Certainly there is no pronounced warnings against plugging your 3-amp vacuum cleaner into the fairly standard 15 or 20 amp circuit. The motor will simply draw what it needs. Am I wrong in this presumption?
              One of the main deciding factors in how big a bang you get if something shorts out is the fault current capacity of the supply. For most domestic installations this is quite small. It's only with commercial and industrial installations that are fed by a large, nearby transformer that this can be high and we use things such as fault current limiting fuses to throttle it. Here in Australia it's the responsibilty of the electrician to consider what the fault current will be when he designs an electrical installation.
              Of course it would be best if an appliance is used on a circuit with a rating not considerably higher than the appliance but it is because the fault current capacity has been thought of that you don't end up engulfed in a fireball when your electric shaver develops a short.

              Comment


              • #22
                Originally posted by briselec
                It takes less than an amp to kill you. In other words, playing around with an outlet is just as dangerous as a panel.
                That's why i don't work on hot panel's if i don't have to.

                [QUOTE=briselec]You still need a circuit breaker regardless. What I meant was that the best way of protecting a motor is with an adjustable overload as commonly used with 3 phase motor starters. A bit of an overkill for a 220V saw.

                You still need a circuit breaker but take out the dryer's 30 amp breaker and replace it with a 75 amp or 50 amp breaker. From there run power to a sub panel near or in your garage. Then you can have the dryer pulled from there and your outlets for your shop. A 75 amp panel is usually what we us when finishing someones basement. This is really the smartest thing to do for your saws needs.

                You need to have a dedicated breaker for the dryer. If i just spent $560 on a saw i wouldn't try any shortcuts to power it.
                Last edited by Polar Sparky 1224; 04-16-2006, 02:40 PM.
                "Diplomacy is saying nice dodging until you can find a rock." Will Rogers
                "If a Monkey can do your job, are you in the right profession?

                Comment


                • #23
                  Originally posted by Polar Sparky 1224
                  You still need a circuit breaker but take out the dryer's 30 amp breaker and replace it with a 75 amp or 50 amp breaker. From there run power to a sub panel near or in your garage. Then you can have the dryer pulled from there and your outlets for your shop. A 75 amp panel is usually what we us when finishing someones basement. This is really the smartest thing to do for your saws needs.

                  You need to have a breaker for the dryer only.

                  Polar Sparky,

                  If I understand you correctly, you're suggesting replacing the original breaker to a higher 50 or 75 amp, and replacing the existing line in order to handle this heavier load to a new box (located in the laundry and workshop area); but now you're not going to "breaker" the saw? Isn't this contrary to what was stated before? Now the saw is connected into a 50 or 75 amp line and not the existing 30 amp, which was thought to be a danger!

                  Thanks (and last question from me on the subject),

                  CWS

                  Comment


                  • #24
                    Sorry, i meant to say the dryer is on a dedicated circuit and you have the outlets for your shop powered by the new sub panel. It is kind of hard to connect you black wires to the panel without using a breaker though. It is kind of a given that anytime you have devices getting power from a panel you need to have a breaker to get them powered in the first place.
                    "Diplomacy is saying nice dodging until you can find a rock." Will Rogers
                    "If a Monkey can do your job, are you in the right profession?

                    Comment


                    • #25
                      Let me see if I can make this clear. Take the 30 amp feed to the dryer and hook it to the new sub panel. At the new sub panel it gets split 30 amps to the dryer and 15 to the saw. Now 30 plus 15 is 45. The breaker at the main panel now needs to be at least 45 amps. So replace it with a 50. My only concern is the gauge of the wire to the dryer to begin with. Will it handle 50 amps?
                      SSG, U.S. Army
                      Retired
                      K.I.S.S., R.T.F.M.

                      Comment


                      • #26
                        Sorry should have been more clear.

                        Take 4 AWG aluminum service entrance cable cable from the 75 amp breaker that took the place of the dryer breaker. This wire feeds you sub panel with from which you run 10 AWG to you dryer and 12 AWG to the added circuits for your shop. You then have 45 amps left over which should be plenty for your shops needs. You can also use 10 AWG for you TS3650. Bigger wire doesn't change the amps of the circuit since the circuit breaker determines the amps running down your wire. 12 AWG THHN at 194 degree's Fahrenheit can handle 30 amps but you need that extra capacity so that if a spike or surge happens you don't burn up your wire.

                        Even then your home's service is sized based on square feet and your AC, Range, Dryer, Water heater, Electric heat, 3 Volt/Amps per square foot plus 1500 VA's for each small appliance circuit in your kitchen, and 1500 VA's for you laundry room outlets. (the first 3000 of this is counted at 100% and 35% of the remainder from 3001 to 120,000.)
                        "Diplomacy is saying nice dodging until you can find a rock." Will Rogers
                        "If a Monkey can do your job, are you in the right profession?

                        Comment


                        • #27
                          I,ve been reading all the posts here and to mee it seems the cwsmith is the only one who has a clue

                          polar sparky needs to go back to school and stop giving bad advice your gonna get someone killed.

                          first of read article240.6 (a) 75 is not a standard fuse size so no fuse or breakers are manufactured at this amperage so you need to pay more attention on the job or find a new profession
                          some of what you say is correct but not for the application in which you apply it to.
                          i've never seen a 75 amp panel they dont make one they do make a 60,or a 125 then you go on to talk about a three phase motor starter you make no sense.
                          next 30 amps for # 12 thhn?? i'll just leave that one alone (310.16)

                          you also forgot that a dryer circuit is typicaly 4 wire (2 hots 1 neutral and 1 ground) the saw evryone is refering to should be 3 wire (2 hots 1 ground) which in the electrical industry is called a balanced load.

                          a simple solution would be:

                          if the dryer outlet is in close vecinity to the saw you are trying to operate just simply make an extention cord out of # 10 wire with a dryer plug on one end and get a simple 30 amp fused dusconect which can be fused at 15, 20 or what ever attach this disconect to the table then from the disconect you can now pull a 220v. receptacle which would be protected, cost efficiant and safe.
                          you wont have to worry about the dryer being used at the same time because the plug will be utilized at the time the saw is on and when you want to use the dryer just unplug the saw.

                          I would be very careful as to what advice i would seek from polar
                          I have read just about every post by you and they are either wrong or you simply don't know what you are talking about.
                          this is the same guy who said not to install a gfci in an unfinished basement because of neusanse tripping eaven though it is a damp location "just get a rubber mat" lol
                          I espesially like how you have told evryone how to install a 75 amp subpanel on 30 amp rated wire.

                          you should atleast know the code before quoting it.or is this what the electric schools in utah teach??

                          by your responses you have proven your electrical skill and knoledge which are like your 75 amp breaker non existant.
                          Last edited by MD MASTER SPARKY; 04-17-2006, 02:28 PM.

                          Comment


                          • #28
                            one thing i was watching this forum for quite a while but the way it gone i going to agree with MD master sparky with this one and i dont see 75 amp fuse or breaker as standard size at all

                            i dont know who idea to increase the breaker size to much bigger on dryer circuit this is very insane to do this

                            i will never do this fashion of set up either run new subfeed box to garage or use the fused or breaker box as MD master sparky suggest from dryer rep.

                            i am sorry but i have to step in and stop this before it got out of hand and someone get hurt or destory the wires along the way

                            Merci , Marc

                            [ master electrician both usa and france ]

                            Comment


                            • #29
                              Originally posted by Polar Sparky 1224
                              Take 4 AWG aluminum service entrance cable cable from the 75 amp breaker that took the place of the dryer breaker.
                              Could you please explain this to me? Why such large wire? Where do you get a 75 amp breaker? Where do you get a 75 amp subpanel? Who's gonna inspect and pass this piece of electrical devestation?

                              Originally posted by Polar Sparky 1224
                              This wire feeds you sub panel with from which you run 10 AWG to you dryer and 12 AWG to the added circuits for your shop. You then have 45 amps left over for your shop needs.
                              Why do all the breakers in my panel add up to over 300 amps but yet I never trip the main with a 200 amp panel?

                              I only ask these questions because I don't understand your logic in them. As a licensed elctrician like you've stated you are where did you come up with this?

                              This is not a shot at you in anyway, so I don't wanna feel any hard feelings from you.
                              Last edited by swoosh81; 04-17-2006, 09:17 PM.

                              Comment


                              • #30
                                Cousin Vinny always said a penny works better anyways.
                                Too bad about the fire.... lost his whole place and insurance wouldn't pay 'cause of a penny.

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