Page 1 of 2 12 LastLast
Results 1 to 15 of 27

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

  1. #1

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

    I would like to mount the switch for my Grizzly G0442 Dust collector inside the shop and will run power to that via conduit from a junction box on the wall but I would then like to pass the power cable from the switch to the motor through the wall to the DC closet I built without going through a pair of junction boxes. I am imagining just passing a piece of 3/4 conduit through the wall connected to two wall plates with cable compression fittings but I'm coming up short finding compression fittings that will connect directly to conduit. All the ones I have found at the borg are meant to connect to a junction box.

    Looking for ideas, recommendations or alternatives to make this work without cutting the stock cable.

  2. #2
    Is it an actual wall, or just an "enclosure" around your dust collector? Cords aren't supposed to go through walls, per the NEC. If it is a real wall, you'll need to do it with real wiring, not SJO.

  3. #3
    Quote Originally Posted by Andrew Seemann View Post
    Is it an actual wall, or just an "enclosure" around your dust collector? Cords aren't supposed to go through walls, per the NEC. If it is a real wall, you'll need to do it with real wiring, not SJO.
    Actually it is kind of both an enclosure and a real wall. I built an addition to my shop specifically for the dust collector. It is attached to what was originally an exterior wall. The addition is sided, roofed, insulated and now has openings for the Main DC trunk with return air vents so technically it is an enclosure but access to the enclosure is external to the shop.

    It makes little sense to me in this case to install two junction boxes on ether side of the wall, join them together with an inch of conduit, cut the power cable and then proceed to rejoin the cable in each box with wire nuts when passing the wire though the wall in conduit is effectively the the same. It is enclosed and not exposed to drywall and insulation.

    DC_Closet.jpg WIN_20190922_17_17_47_Pro.jpg

  4. #4
    Instead of conduit you might run a steel water pipe through the wall and put a floor flange on both size. You might have to get someone to make a threaded nipple to the correct size so the floor flange would tighten up on both sides.

  5. #5
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    50,260
    Andrew is correct...not really the right thing to do, despite the fact that folks do it all the time. It's not all that difficult or expensive to do it to code, honestly.
    --

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

  6. #6
    Join Date
    Apr 2013
    Location
    Okotoks AB
    Posts
    1,449
    Doing it to code will actually be simpler that what you are trying to do with compression fittings, etc. It could be done in the time it took to look for fittings that don't exist & then ask on this forum.

  7. #7
    Join Date
    Feb 2003
    Location
    Griswold Connecticut
    Posts
    6,473
    Isn't there a wireless remote system for this application type???
    "The first thing you need to know, will likely be the last thing you learn." (Unknown)

  8. #8
    Quote Originally Posted by Tom Dixon View Post
    I would like to mount the switch for my Grizzly G0442 Dust collector inside the shop and will run power to that via conduit from a junction box on the wall but I would then like to pass the power cable from the switch to the motor through the wall to the DC closet I built without going through a pair of junction boxes. I am imagining just passing a piece of 3/4 conduit through the wall connected to two wall plates with cable compression fittings but I'm coming up short finding compression fittings that will connect directly to conduit. All the ones I have found at the borg are meant to connect to a junction box.

    Looking for ideas, recommendations or alternatives to make this work without cutting the stock cable.
    I'll ignore the code violation issues, since they have already been discussed... But it seems a remote, if the signal will pass through the wall, would be easiest.

    If I understand your intent correctly, you want cable compression fittings on either end of a conduit you intend to pass through the wall. The only way to do that with EMT is to put connectors on each end of the pipe, add a threaded coupling (I usually cut them in half when connecting fittings) and screw a cord compression fitting to that.

    If you want it hard-wired (and within code), run a conduit from the power junction box feeding your DC into your workshop and install a disconnect wherever you want the switch. Or, if the feed to the DC runs through your shop, you could break into the pipe feeding the DC and install a disconnect at the break.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

    Diapers and Politicians need to be changed often... Usually for the same reason.

  9. #9
    Quote Originally Posted by Julie Moriarty View Post
    I'll ignore the code violation issues, since they have already been discussed... But it seems a remote, if the signal will pass through the wall, would be easiest.

    If I understand your intent correctly, you want cable compression fittings on either end of a conduit you intend to pass through the wall. The only way to do that with EMT is to put connectors on each end of the pipe, add a threaded coupling (I usually cut them in half when connecting fittings) and screw a cord compression fitting to that.

    If you want it hard-wired (and within code), run a conduit from the power junction box feeding your DC into your workshop and install a disconnect wherever you want the switch. Or, if the feed to the DC runs through your shop, you could break into the pipe feeding the DC and install a disconnect at the break.
    The remote switch is Infrared and not RF so leaving it attached to the DC in the external DC room is not really an option. I will mount the whole switch assembly on the shop side of the wall and power to it can either be through conduit from the existing circuit I dedicated to a DC when I built the shop, or by using an L6-30 plug and 10Ga cord like what runs from the switch to the motor. The weird thing about the Grizzly power recommendation is that the G0442 current rating is 22.4 Amps but the recommended circuit rating is 40 Amps. I can only assume it can draw over 30 amps when the motor starts but normal running is 22.4. When I built my shop I told the electrician I needed a 40 Amp circuit. What he ended up installing was a 50 Amp breaker, a L6-50R and used 8Ga wire. I'll have to replace the breaker with a 40 Amp but I'm unsure if I should leave the 8Ga or re-pull 10Ga. I'm inclined to leave the wiring from the panel to the box as it is and use a L6-30 plug so I have a power disconnect at the junction box rather than direct wiring from the box to the switch.

    In the photo below incoming power is not shown but there is an unused strain relief showing wher the power is supposed to be connected.

    Attachment 416697

    After doing a bit of searching I think I can get 3/4 PVC conduit, PVC threaded connectors and PVC compression Connectors for a through the wall connection of the existing cord. I just may have to order the compression connectors but I won't be worrying about completing the wiring until the weekend when I mount the switch assembly inside the shop.

  10. #10
    Yeah, leave the #8 wire in place. No harm doing that. But replace the 50A breaker with a 40A to keep within manufacturer recommendations. That amperage difference between the breaker and actual load is, as you suspected, to deal with startup spike.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

    Diapers and Politicians need to be changed often... Usually for the same reason.

  11. #11
    Join Date
    Aug 2019
    Location
    USVI
    Posts
    89
    I’m thinking one of these boxes on each side of the wall with a short piece of conduit in between
    77C112C5-3204-40FF-92A3-C9901751B603.jpg
    Maybe switch to a short section of flexible into the DC in case of any vibration. Should be able to pull the motor wires through without cutting. Probably not to code as I’m no electrician so ymmv
    0A0C46C3-E117-4A64-8814-B5D53F11539D.jpg
    Last edited by Steve Fish; 09-24-2019 at 8:20 AM.

  12. #12
    Look for an "IR repeater" - it would let you put the "sensor" for the remote in your shop, and the "transmitter" could be placed right next to the remote control receiver on the cyclone. Just a thin wire runs between the parts.

    Because the unit has a magnetic starter, you can't simply switch the 30A/240V, even if you wanted to. If the IR repeater doesn't strike your fancy, your other option is to put a set of pushbutton switches to control the magnetic starter. It may still be 240V, but would only be a fraction of an amp.

  13. #13
    Quote Originally Posted by Dan Friedrichs View Post
    Look for an "IR repeater" - it would let you put the "sensor" for the remote in your shop, and the "transmitter" could be placed right next to the remote control receiver on the cyclone. Just a thin wire runs between the parts.

    Because the unit has a magnetic starter, you can't simply switch the 30A/240V, even if you wanted to. If the IR repeater doesn't strike your fancy, your other option is to put a set of pushbutton switches to control the magnetic starter. It may still be 240V, but would only be a fraction of an amp.
    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.

    Solution.jpg file.jpg
    Last edited by Tom Dixon; 09-25-2019 at 12:29 AM.

  14. #14
    For all the effort you are going through, you might as well do it legal and just put junction boxes in on each side with conduit and listed wire in between or just run some 8/2 NMB from the switch through the wall to the motor.

    If you are going to do it illegally, just put a deburred 1" water pipe nipple in. The whole point of not allowing cord to go through a wall is because you can't see if it has degraded inside the wall. Fixing it with strain relief prevents you from checking on the cord's condition every once in a while, which is, again, the reason you are not supposed to do it in the first place.
    Last edited by Andrew Seemann; 09-25-2019 at 1:31 AM.

  15. #15
    Quote Originally Posted by Andrew Seemann View Post
    For all the effort you are going through, you might as well do it legal and just put junction boxes in on each side with conduit and listed wire in between or just run some 8/2 NMB from the switch through the wall to the motor.

    If you are going to do it illegally, just put a deburred 1" water pipe nipple in. The whole point of not allowing cord to go through a wall is because you can't see if it has degraded inside the wall. Fixing it with strain relief prevents you from checking on the cord's condition every once in a while, which is, again, the reason you are not supposed to do it in the first place.
    Steps to inspect power cord:
    1. Unscrew strain relief compression nuts.
    2. Inspect power cord wire.
    3. Replace if degraded or return strain relief compression nuts.

    I seriously doubt this cord will degrade to a point of needing replacement in my lifetime. It will be 8 feet off the floor in the shop and 5 feet from the floor in the DC closet, under no strain and not likely to be physically damaged by equipment or abuse. I also seriously doubt I will ever see a county electrical inspector come to my shop and tell me I didn't follow code and require me to do it differently. As for the effort required it is significantly less than installing two junction boxes connected by conduit in an existing wall and insure they are properly secured. The way I plan to do this may not be strictly legal but I do not consider it unsafe in this case.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •