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Thread: How to safely pass a 30 amp 220 electrical cord through a wall

  1. #16
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    Your DC should have it's own breaker inside the shop as well as as a disconnect outside visible while working on the machine in the closet. I do not see any advantage to moving starter inside. If you do that you need to add another switch or cord end/recipticle outside as a required visible disconnect.
    Dan beat me to it. It is easier and cheaper to add a repeater or a fiberoptic line between the inside and outside.
    Bill D.

  2. #17
    Quote Originally Posted by Tom Dixon View Post
    Dan, I think you are confusing what I want to do. I'm not replacing the switch. I'm simply placing it in the Shop instead of the DC closet. I believe I came up with a viable solution today shopping at Home Depot. I already had a short piece of 3/4 PVC conduit so I purchased 2 3/4 female threaded adapters, 2 3/4 in. Strain Relief Cord Connectors, 2 PVC face plates, a 40 Amp breaker a L6-30R and L6-30P, all but the breaker pictured below with the 10AWG wire that will connect to the empty strain relief of the switch assembly in the second photo. The wire shown above the switch assembly will go through the wall and connect to the motor where I disconnected it before installing the motor/impeller housing on the cyclone. I'll drill an appropriately sized hole in each of the face plates, the conduit with adapters will go through a hole in the wall and the strain reliefs will go through the face plates to screw into the threaded adapters and then be attached to the walls with 4 screws.

    Although the idea of an IR Repeater is a pretty good one it would mean I would not have ready access to the actual power switch in the shop if for some reason I needed to kill the power.
    Oh, I see - you're moving the starter to the "other side" of the wall. Sorry for my confusion - I thought you were putting a switch between the motor and the starter.

    I think I agree with you that what you propose is not "unsafe". Technically the cord shouldn't be run through the wall (and not because of inability to detect degradation - but because wire is rated for a particular amperage based on the thermal insulation of the rubber/plastic/conduit around it, and you've taken a cord that was designed to be "out in the open" where it more easily dissipates heat and packed it into a conduit into a wall).

    I would definitely suggest you reconsider wiring a remote start/stop switch to the starter. Remote control of motors is literally one of the primary purposes of motor starters. You have a need to control a motor from a remote location and already have a starter....seems pretty logical That would be the "proper" way to do it.

  3. #18
    This where a good starter that lets you run multiple 3 wire push button stations comes in handy. A couple LBs, some conduit, some small wire and voila, pushbuttons wherever you want. I would add a disconnect someplace too.

  4. #19
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    Have you considered simply putting a contractor (relay) on the first collector side of the wall and running simple 12 V or 24 V to the shop side?

    That would keep all of your 240 V on the one side and avoid all of the complications going through the wall, etc., since low-voltage (think doorbell/garage door wiring) requires no conduit, can be stapled (preferably protected from staples' sharp edges) and is much cheaper.

    Your contractor can be standard on-when-energized, or can toggle on-off with momentary doorbell-style button.

  5. #20
    OK to help clear up some of the confusion why I want the switch assembly inside, it will be clearer to you if you examine the switch control box illustration from the manual below. The switch is not just an IR on off device. It also is a timer, has indicator lights for overload, timer settings, power indicator and a mechanical power cutoff switch. Putting it in the DC closet robs me of these features. Any suggestion that I should put the switch in the DC closet is therefore off the table. It ain't going to happen.

    The DC will have it's own dedicated 40 Amp circuit with a dedicated 40 Amp breaker and a L6-30P for complete power disconnect inside the shop, (I thought would be understood after my exchange with Julie Moriarty).

    I will admit that after listening to some of the suggestions I am now considering options for a separate power disconnect in the DC closet. If I do put a disconnect in the DC closet I am weighing whether a single box with an L6-30R and an L6-30P on the motor cord would be the best option or if I should look at some other kind of less expensive mechanical cutoff switch. I'm still not absolutely convinced a separate cutoff is necessary since I would have three methods of cutting power inside the shop, (breaker, switch and plug).

    switch.JPG
    Last edited by Tom Dixon; 09-25-2019 at 10:34 PM.

  6. #21
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    NEC says you have to have a disconnect visible from the motor. What happens if you are working on the fan and someone turns it on inside?
    Of course running a cord through a wall is not to code so why worry about another minor safety thing.
    Bil lD

  7. #22
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    I used a receptacle/plug combination as a disconnect for my Oneida cyclone in the closet. While I'm using a contactor with 120v remote control for switching the system on/off, the principle is the same as for what you have. You just have more bells and whistles at the "control". I have a single, centrally located wall switch. There should be some way for you to properly extend the lead between your control box that will live in the shop and the power connection equipment in the closet near the cyclone. Yes, that might require using j-boxes, etc., but in the end, it's only going to take you a short period of time to wire that in and there will be no concerns about the legitimacy of your wiring should the unthinkable happen.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  8. #23
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    I just realized the younger set would leave the switch outside with a remote booster to get through the wall and set up a webcam so they can see the controller on their cell phone from anywhere in the shop.
    Bill D

  9. #24
    UNCLE!
    OK, alright, and you made me say it, and say it loudly. You've convinced me to put in a cutoff in the DC closet. One can be stubborn only for so long in the face of logical arguments and the occasional biting sarcastic comment. The decision now is whether to just put a plug in the DC closet or use something like this Square-D 60-Amp Non-Fusible Non-Metallic-Enclosed Circuit-Breaker safety switch. I would rather it be a 40 Amp breaker, and I may be able to order that as a replacement online, but the 40 Amp breaker for the circuit in my main panel will trip if exceeding 40 Amps. I like the idea of a switch better than a plug.

    Expecting opinions in 3... 2... 1...


  10. #25
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    A plug is a "switch"...it's just not as pretty. Use what works best for you! If your machine requires a 40 amp circuit and that's how you wired it up, staying consistent makes sense relative to that part of your question.

    As an aside, I actually do use a plug as a disconnect for my CNC machine to insure it's totally isolated when not in use because of the sensitive electronics. Lightning happens. A more formal switch for a four-wire 240/120 circuit wasn't something I wanted to deal with and I didn't want to totally hard wire it like some do per the manufacturer's setup instructions. For the cyclone, I already had a dedicated outlet for it in my closet and my contactor was right next to it on the wall. So a short pigtail from the contactor enclosure with a plug did the deed. If I were moving and designing a new shop, I might do something more formal like you show in your photo, however.
    Last edited by Jim Becker; 09-26-2019 at 3:52 PM.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  11. #26
    Quote Originally Posted by Jim Becker View Post
    A plug is a switch...it's just not as pretty. Use what works best for you!
    The reason I gravitated towards using a switch is it costs $14.00. A L6-30P and a L6-30R together are about $50.00. I can afford that but...
    Last edited by Tom Dixon; 09-26-2019 at 5:24 PM.

  12. #27
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    I don't disagree with that, Tom. And for the CNC, it was L14s. Fortunately, Amazon has good prices on such things. Again, do it the way that you feel most comfortable with both technically and aesthetically, especially for a brand spankin' new shop space!
    --

    The most expensive tool is the one you buy "cheaply" and often...

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