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Thread: Life cycle of 240v plugs

  1. #1

    Life cycle of 240v plugs

    I wired my entire shop and used standard 40 amp receptacles and plugs on all my 240v tools, so in case I rearrange the shop, I can plug any tool into any outlet. All the circuits go into a subpanel I added in the shop.

    When I leave the shop, I unplug all my tools from the wall, to protect them from power surges. Especially my Clearvue cyclone, I have that wired to a remote control and I dont want that sucker coming on while I'm away due to an errant radio signal. I am in the shop 4 or 5 days a week, so there is a lot of plugging and unplugging going on.

    I can't find any information on whether the plugs/receptacles can handle this long term. In hindsight, I guess I should have used all twist lock plugs. Does anyone know if this is actually an issue? After a year of doing this, the plugs stiil take a lot of effort to insert and remove, so I don't think they have worn down at all. I would prefer not to use the breakers to disable the tools, and I'm not even sure if that would protect them from power surges anyway. Any input would be appreciated. Thanks

    Brian

  2. #2
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    Sorry, but I think your worrying about nothing......

    Be easier to just flip the main on the sub panel if you want things shut off.

    Ed

  3. #3
    Join Date
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    Yup, as above.

    Marc
    I'm pretty new here, not as as experienced as most. Please don't hesitate to correct me

  4. #4
    Will flipping the main prevent a power surge from zapping my tools?

  5. #5
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    Yes.

    Once the main is thrown that's the end of the line.

    By shutting off the main you have no risk of damage to anything except the main breaker itself.

    Ed

  6. #6
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    I'll have to somewhat disagree with breaker disconnection being the "end of the line" relative to surges as an absolute. A large surge can jump an open breaker if it really wants to. (A friend had that happen not long ago) This is why I tend to unplug my CNC when heavy storms are expected. I don't unplug other things in my shop, however. That said, "most of the time", flipping the main breaker can serve to help protect from "reasonable" surges.

    For the original question...I seriously doubt that you'll wear out any of those plugs in your lifetime unless one or more are defective...
    --

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

  7. #7
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    Receptacle do wear out, but you'll know when they do and can replace them easy enough. How long would depend on how often it's being disconnected, the original quality of the component, and how aggressively you're disconnecting them. Twist lock plugs are nice because you can't just "snap" the cord out of the receptacle. You have to remove it at the receptacle by hand.
    Any device that has a microprocessor in it, for any reason, is not truly protected from power surges, unless it is unplugged. Devices such as these need either surge protectors/transient eliminators, or unplugged.
    "The first thing you need to know, will likely be the last thing you learn." (Unknown)

  8. #8
    Thanks for the input. I will keep unplugging them. I'd rather take 1 minute to unplug my tools to avoid replacing a bunch of 3 and 5 hp motors in the event of a power surge. I had a suspicion that a large surge could jump an open breaker as Jim stated .

  9. #9
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    Quote Originally Posted by Brian Behrens View Post
    When I leave the shop, I unplug all my tools from the wall, to protect them from power surges. Especially my Clearvue cyclone, I have that wired to a remote control and I dont want that sucker coming on while I'm away due to an errant radio signal.
    ...
    As for the ClearVue, I have the remote electronics they sold which use 120v to trigger a contactor (relay). To prevent errant signals from turning the cyclone on I put a switch in line with the 120v to disable the contactor. I actually put two switches in series, one in the closet and one in the shop. These switches have pilot lights on them so I can see from a distance if they are on. Nothing may stop lightning from damaging things (the surge can come though the ground or common) but switching off the control power would eliminate any triggering by errant signals or even a compromised control circuit board.

    I also have a heavy-duty motor disconnect on the 240v to the contactor and cyclone motor but I don't turn it off unless needed for service.

    JKJ

  10. #10
    A breaker creates a space between the contacts. Unplugging the tool also creates a space between the contacts. If you unplug a tool but leave the plug laying near the receptacle, the space between those may be less than the space between the contacts in a breaker. Unplugging is just giving the possibility of more separation. Lightning is jumping thousands of feet, though, so the difference between 0.25" in a breaker or 4" between a cord and plug is a very minor difference...

    Realistically, it is unlikely a surge exists which jumps a large breaker. It is also VERY unlikely that a surge damages a large motor (even with it connected).

    I agree with others that you need not worry about lifecycle of plugs, but also agree that it's borderline crazy to unplug tools in lieu of flipping a main breaker.

  11. #11
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    You could put a nice big disconnect before your breaker panel and shut the shop off with it.

    https://www.homedepot.com/p/GE-100-A...3223/202978655

  12. #12
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    One thing I did when building and wiring my shop was to use commercial grade outlets. They have beefier internal components and should stand up to repeated use. I also use twist-lock plugs and outlets for my 240 volt machines. It may be overkill but I feel better using these as opposed to the standard plug straight in pieces.

  13. #13
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    My large tools have disconnects. All the tools i build do too.

  14. #14
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    Quote Originally Posted by Dan Friedrichs View Post
    A breaker creates a space between the contacts. Unplugging the tool also creates a space between the contacts. If you unplug a tool but leave the plug laying near the receptacle, the space between those may be less than the space between the contacts in a breaker. Unplugging is just giving the possibility of more separation. Lightning is jumping thousands of feet, though, so the difference between 0.25" in a breaker or 4" between a cord and plug is a very minor difference...

    Realistically, it is unlikely a surge exists which jumps a large breaker. It is also VERY unlikely that a surge damages a large motor (even with it connected).

    I agree with others that you need not worry about lifecycle of plugs, but also agree that it's borderline crazy to unplug tools in lieu of flipping a main breaker.
    Agree it's very unlikely. I've actually had a large surge issue of sorts. Lightning hit a tree beside my shop, jumped from a root to a sprinkler control wire, and entered my shop. Blew up the sprinkler controller and destroyed the plug it was using. I had some tripped breakers in the shop sub-panel, none in the main, and no other damage. However it did light a fire that miraculously put itself out. I wasn't home at the time, so I'm very lucky the fire went out by itself. I had a Felder combo machine, with lots of electronics, and at least 5 other machines plugged in. No damage to any. Did kill the microwave in the kitchen next door and a A/V receiver.

    Honestly, after seeing how that bolt peeled the bark off the tree, literally blew up the ground at the root, arced into the double insulated sprinkler wire, exploded the sprinkler controller all over the shop, destroyed the plug (which caused the fire) and toasted the ground rod clamp, there isn't much anyone could have done to prevent the damage. That much power is so far outside the operating specs of electrical components that it'd be impossible to fully protect from a direct strike like that.

    I'd recommend an insurance policy, then just quit worrying about something that will likely never happen, and if it does, will still cause mayhem regardless of your preparations.

  15. #15
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    Oh yeah, lightning does crazy things. We were building a 10 story office building and I got to work one morning and one of the guys comes up to me and says some of the temp lights were out. So I grab my Wiggy and head for the building. Then the iron worker in the trailer next to ours says he's getting a shock from the door handle. I checked and sure enough the door handle was getting 50v.

    When I entered the building I saw some temp lights out, some dim and some burning bright. Then the manlift operator tells me the skip isn't working. I checked it and the 480v feed was fine but the controller circuit was fried. When I checked the temp power for the building I found one phase on the transformer was dead, the other was putting out 50 volts and the third phase was reading 150v.

    As I was walking back to our trailer I saw the door fly open and a flaming phone fly out the door. The general foreman followed screaming, "The phone caught on fire while I was talking on it!"

    Best I could figure out was we got hit by lightning. We brought in a new transformer and were back online.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

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

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