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  • 220 volt distribution in a shop

    If (when) I convert my tools from 110 to 220 volts, I certainly don't want to continue to use the standard 110 volt style outlets to supply 220 volts around the shop. But the big orange box has several different plug/outlet styles for 220 volts.

    Is there a "standard" or "most common" 220 volt plug/outlet style to provide the "under 15 amps" for power tools such as Saw, Jointer, etc.

    I plan to bring a new 20-30 amp 220 volt service from the main box to a single outlet in the shop, then plug in a distribution panel (so the rest of the system is isolated from the "permanent wiring" rules, and so I can move it if the shop moves). The distribution panel would have loops for ammeter and "extension cord" type runs around the wall or hanging from the ceiling to the positions where the tools most often are used in the garage. Any suggestions/warnings with this approach?

    Some dust collector forums suggest that the ground wire required to disperse static electricity in PVC pipe only needs to run along or inside the pipe and be connected at the grounding end, like an antenna. Can the flex power lead, with it's ground wire, be snaked inside the planned PVC dust collector pipe, and be brought out at the blast gate, providing the DC grounding? In a rolling shop, dust collection and power have to go to the same points!

  • #2
    If (when) I convert my tools from 110 to 220 volts, I certainly don't want to continue to use the standard 110 volt style outlets to supply 220 volts around the shop.

    For sure. That's not only a code violation, it's terribly dangerous should someone have a momentary lapse and plug a 110v device in. I'm just the guy that would happen to, you know?

    But the big orange box has several different plug/outlet styles for 220 volts.

    There are three and four conductor 220v outlet types. The four conductor are for devices with 220v and 110v loads, like an electric range (elements are 220v, lights and electronics at 110v). Three conductor are for "pure" 220v.

    There also are choices of locking and non-locking receptacles. My preference is for whichever pair you can find that come apart easier. Some non-locking types are incredibly stiff.

    Then, there is the rated amperage for each receptacle.

    Is there a "standard" or "most common" 220 volt plug/outlet style to provide the "under 15 amps" for power tools such as Saw, Jointer, etc.

    NEMA* has standard codes for these parts. For 220v household parts, these look as such: 6-30R, 6-30P, where the code breaks down like this

    6- - 250V two-pole, three wire grounding.
    30 - rated amperage, match this to circuit breaker/wire size.
    R or P - receptacle or plug.

    A locking pair will have an "L" on the front, as in L6-30P.

    The NEMA code is embossed into the part itself on every one I've ever seen. The numbers are of course incredibly tiny, I have to have good light to see them.

    I plan to bring a new 20-30 amp 220 volt service from the main box to a single outlet in the shop, then plug in a distribution panel (so the rest of the system is isolated from the "permanent wiring" rules, and so I can move it if the shop moves).

    Bounce that exemption off your AHJ or a licensed Electrician.

    I strongly suggest using at least a 60 amp distribution. The price of parts is nearly the same, and a larger subpanel gives tons more flexibility. My subpanel is a 150 amp SquareD Homeline that I caught on sale at the Borg for about $80, with 8 20a single pole breakers tossed in. A smaller panel only would have cost nearly the same, and I have loads of space for circuits.

    Can the flex power lead, with it's ground wire, be snaked inside the planned PVC dust collector pipe, and be brought out at the blast gate, providing the DC grounding?

    My guess is no, on two fronts.
    1) Running an insulated power line inside the duct wouldn't do anything for static dissipation, you need a bare wire for this.
    2) Sawdust is very abrasive, especially at 30-40mph. I would be concerned about hidden damage to the power line insulation, and I would bet that this type of installation would not be allowed by code.

    Dave

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    • #3
      1. You can't ground PVC.
      2. After you use it for awhile it will disapate the static pretty good. I have had mine for about 5 years & don't get any static at all.
      3.I use a 3 prong plug made for 220 volt not a locking plug because if you use a locking plug & something catches the cord you'll break the wall plug.

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      • #4
        Guys,

        As long as we are on this topic. I got a few questions. I am in the process of wiring my shop. I am starting from nothing. I got a SquareD Homeline 100 Amp load center (value pack = with 5 20 amp breakers) ($48.00 @ Menards) and need to hook it up.

        Lets start with the basics. I will ask more later.

        What gauge wire do I use to connect it to the main load center?
        Where do I connect it to the main load center?
        Currently, the max draw will not be more than 30 amps. I currently have a 100 amp main but plan to upgrade to 200 down the road and do not want to redo the shop once that happens.
        Should I put GFI outlets in? If so, what amp? 15 or 20? Should it match the circuit breaker of that circuit?
        Should I run 220 in the same conduit (different circuit) that I run the 110 in?
        If a piece if equipment is rated at 15 amps, like my air compressor, should I use a 15 amp or 20 amp breaker (assuming only the compressor will be connected to that circuit)?

        Since this is a garage, should the garage door opener be on the same circuit as the lights or not.

        I do plan on several 220 circuits (with 3 prong non locking outlets) and will convert all applicable equipment to 220. I am thinking about going with 15 amp outlets. Once again, do the ratings of the outlets need to match the breaker of the circuit?

        I know some of this depends on the code in the community but opinions are greatly appreciated.

        Charlie, as far as grounding the PVC for the DC, based on what I have read, I have not worried about it and have not grounded mine yet. My DC runs about 10 to 15 minutes at a time. Maybe 2 to 3 hours total per day of use and I have never been shocked. Lets see what the future brings. If it bites me, I will ground it. Those who claim it should be grounded say that PVC (or other plastic) should be grounded both on the inside and outside with the bare ground wire. Another article I read stated that one should be more concerned about burning wood or a hot chip from a broken blade starting a fire in the DC than the static from the friction. Not sure how true that is. There are so many opinions out there about this that it makes it hard to know what is real and what is fiction.

        Thanks,
        Rob

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        • #5
          Trying to answer in sequence...

          The wire you need from your main box to the shop load center depends comes from a breaker you must add to your main box. The size of the wire depends on the size of the breaker you put in the main box. For a 30 amp breaker, #10 wire. (other sizes to remember, 15 amp is #14, considered obsolete for in-wall wiring, 20 amp is #12) I don't have the capacities above #10 off the top of my head, but bottom line, it is limited by the breaker at the main box. Which, of course, cannot be larger than the 100 amp capacity of the load center. Tentatively I am planning on using a 30 Amp 240 volt service to the shop.

          All my 120 volt runs will be 20 amp, since many machines push the limit of 15 amp service. In order to get UL approval for home use, it must be under 15 amps, because many older homes are only wired for 15 amps, but it is obvious that many of the machines barely make that limit.

          The machines that run 15 amps at 120 volts will only draw 7-8 amps at 240 volts. Since my shop is mobile, and since 14 gauge flexible wire is far more available than 12 gauge flex, I will probably wire the 240 volt for 15 amps. Hint: 14 gauge extension cords are FAR cheaper than buying the same wire by the foot. So cut off the 120 volt plugs.

          I plan on leaving the garage door and lights on the household circuit, so I can turn off the shop for safety or when doing alterations, and allow the garage to be used normally.

          GFI circuits only protect if the going and returning electric are different... if you use a 3 prong plug, or if you drop the appliance into water that is connected to ground. They are not recommended for refrigerators/freezers because of the risk of a false trip, and losing the food. But I have never tripped a GFI except to test it, so I'm not excited about that technology.

          If you can manage a loop in each circuit for a clamp on ammeter, we have found that VERY helpful in setting up equipment - for example, increasing the speed of the wide sander until the load on the motor rises...

          As illogical as it sounds, an insulated wire should be a sufficient ground for a dust collector, inside or outsde the pvc, since we are looking at high voltage, high frequency static. But I also have seen many notes, like yours, that say don't bother.

          Comment


          • #6
            GFI circuits only protect if the going and returning electric are different...

            Some local codes flat require them for garages and some other use. Check with local AHJ to be sure.

            But I have never tripped a GFI except to test it, so I'm not excited about that technology.

            Wish I could say that. Once a year or so we manage to trip the one serving our bathrooms...

            Dave

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            • #7
              Have encountered this topic a bit late: no, you cannot power a distribution panel that is screwed to the wall with a flexible, plugged cord. You have to make a permanent installation, and in occupied spaces, this means either conduit (either metallic or non-metallic) or BX (so-called armored flexible cable), and hard-wire the sub-panel feed to a breaker in the main panel.

              Note that in main panels the ground and neutral wires are bonded, but in sub-panels they are NEVER bonded.

              If you go to a supply store (or even HD), you'll find this ribbed flexible blue plastic conduit that I have found quite easy to use. It comes with all sorts of fittings that snap on the end of the ribs, and the lengths can be cut to fit with a hacksaw or sharp knife. It has a tradename that starts with C but which I cannot remember now.

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              • #8
                That blue stuff is referred to in the trade as Smurf tube. I don't know the exact name of it, but you an only use it in inaccessable locations like sheetrocked walls. Anywhere there could be damage, you must use EMT, or the flexible stuff. If subjected to harsh abuse, you need to use heavier pipe.

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