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    An idiotic question about AC and shocks.

    When I was a small child, like some small children do, I would watch my parents turn on the light and be amazed. I'd watch my father work on vehicles and see the screw drivers and think if I just plugged a flat head into a receptacle, the plastic end would light up just like a light bulb.

    I asked my parents, they said no, don't ever do that, but I was so certain, I had to try, and sure enough, I very much got shocked. I was holding the metal part of the screw driver, not the plastic. It hurt, I cried, my mum yelled at my dad, and then we move forward until I was 20.

    At 20, I was with the third girl I had ever been with, which was my second girlfriend (the second girl was more of a friends with benefits thing). Anyway, she had a son and left me one day. We had the perfect relationship. It was very much fake, but we each pretended to be what the other one wanted. That only could last for so long. When she left me, I was at a very low point in my life and decided I was going to move to Colorado.

    My mum freaks out, calls my childhood best friend who lives in Florida to talk some sense into me, but instead, he talks me into going to Florida and said if it didn't work out, he'd pay personally for the trip to Colorado. Long story short, he was poor, turned abusive towards his girlfriend, she left him, he was worse off than me.

    Anyway, one kid says he can take a screwdriver and put it in the receptacle and not get shocked. I bet 20$ he would. He put it in one port of the receptacle, didn't get shocked. Put it in the second, didn't get shocked. I said the receptacle was off. He plugged in a lamp, and sure enough, it worked. It was a 3-prong receptacle, not that it matters much. 15-amp I believe.

    He said it was because he wasn't grounded, which makes sense to me...without ground, AC has nowhere to flow, right? If that's true, why do we have tamper resistant receptacles for houses with children, why did I get shocked as a kid, why did he not get shocked? I was on carpet. He was on rubber shoes, but surely carpet isn't grounded...My skin was more than likely on the carpet, but I don't see why that would matter....
    -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

    #2
    Re: An idiotic question about AC and shocks.

    different people have different skin resistance and capacitive charge to the surroundings.
    also, enviroment.
    what's the floor made of? how damp/dry was the air etc.

    watch
    https://www.youtube.com/watch?v=Lh6Ob1HFC6k

    Comment


      #3
      Re: An idiotic question about AC and shocks.

      Of course you need a return path.
      In Europe we have hot and neutral, the neutral you can touch while being grounded 99% of the time, it will be at ground potential (the other 1% of the time it's not and you die during this test).

      The hot you can touch as long as you are not touching neutral or ground, and ground can of course be whatever path the current can go, for example through a radiator, or through simply damp floor.

      Think of it just like a bird sitting on the powerline, it's just fine as long as it does not touch anything grounded...
      Or think of it another way: take a hot wire and touch it to the floor, carpet etc, do you expect any sparks?
      Next put it against something damp, or against the kitchen sink and see what happens.

      P.S: This is why it's a really good idea to have a GCFI breaker, in every case expect where the neutral is the return path the breaker will trip, like a child poking a screwdriver into a power outlet.
      "The one who says it cannot be done should never interrupt the one who is doing it."

      Comment


        #4
        Re: An idiotic question about AC and shocks.

        Originally posted by stj View Post
        different people have different skin resistance and capacitive charge to the surroundings.
        also, enviroment.
        what's the floor made of? how damp/dry was the air etc.

        watch
        https://www.youtube.com/watch?v=Lh6Ob1HFC6k
        It wasn't him getting shocked. I tried it as well. He claimed if we took our shoes off, then we'd get shocked. Maybe some special tamper resistant outlet? That was almost over half my life ago, so it's a bit hard to remember all the details. Being in Florida, it was very wet and humid, but we were inside, with central air.

        When I was a child, I'm almost remembering putting the screw driver in, nothing happening, and then remember I needed to plug something in the other plug and found a paper clip or something. I know it did more than shock me. It burned the wall and made a lot of the outlet black. I remember that....
        -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

        Comment


          #5
          Re: An idiotic question about AC and shocks.

          Originally posted by Per Hansson View Post
          Of course you need a return path.
          In Europe we have hot and neutral, the neutral you can touch while being grounded 99% of the time, it will be at ground potential (the other 1% of the time it's not and you die during this test).

          The hot you can touch as long as you are not touching neutral or ground, and ground can of course be whatever path the current can go, for example through a radiator, or through simply damp floor.

          Think of it just like a bird sitting on the powerline, it's just fine as long as it does not touch anything grounded...
          Or think of it another way: take a hot wire and touch it to the floor, carpet etc, do you expect any sparks?
          Next put it against something damp, or against the kitchen sink and see what happens.

          P.S: This is why it's a really good idea to have a GCFI breaker, in every case expect where the neutral is the return path the breaker will trip, like a child poking a screwdriver into a power outlet.
          AC still confuses me then. Let's look at two 120VAC's, 120 degrees apart. When one is +120VAC, the other is -120VAC, with a potential difference of 240VAC, right?

          But doesn't the AC flow forwards and then backwards? Forwards, backwards, forwards, backwards? When I was trying to understand AC not too long ago (even three-phase stuff), I thought that's how it was explained to me...just happens so fast, we don't see or feel it.

          Where is the return path there? They say you don't need a neutral or ground to get the 240VAC. I know I don't use any neutral or ground when I'm testing my 240VAC outlets, but I do read 240VAC.....

          So, touching the hot, so long as I'm not grounded (ie, wearing insulated shoes, not touching anything else) shouldn't hurt me? Even at the mains? Or is that enough current where it'll jump through the rubber soles on my shoes? I have 200-amp right now. I'm not going to do that, I'm just curious.

          Finally, I wanted GFCI breakers, the actual electrical engineer we hired to do the work gave us some whole home lightning protector and whole home surge protector and I want to say he was claiming they were equivalent to the GFCIs, but I won't swear on that.

          Are GFCI breakers better than the tamper resistant receptacles, where you need to push equal pressure on both sides at once to not hit plastic? Or should we replace the receptacles she has access to and the breakers as well? She's now interested in receptacles and those little plastic plugs aren't worth a damn anymore. Thanks!
          -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

          Comment


            #6
            Re: An idiotic question about AC and shocks.

            "Finally, I wanted GFCI breakers, the actual electrical engineer we hired to do the work gave us some whole home lightning protector and whole home surge protector and I want to say he was claiming they were equivalent to the GFCIs, but I won't swear on that."
            Maybe he was a train engineer. whole house surge protectors are NOT GFCI's. Whole house surge protectors are equivalent to mov's across the line. they protect from large electrical spikes coming into your home on the power line, and may protect your electronics and appliances, but it won't protect you.

            You don't need a ground or neutral to have 240vac, but you should always have a ground. and some appliances require a neutral, ie electric clothes dryer, Uses 240 for the element but the motor etc. usually runs on 120.

            GFCI's are better than tamper proof plugs, if a cord is pluged in but the wire in the cord itself is damaged/exposed, the tamper proof receptical won't protect against that but the gfci will.
            Last edited by R_J; 06-09-2018, 10:35 AM.

            Comment


              #7
              Re: An idiotic question about AC and shocks.

              I think they want TR outlets because they're... cheaper.

              They say TR outlets cost $0.50 more to make, GFCIs are like 6x the cost at least.

              Granted last I went by the Despot, the TR outlets were fairly pricey... but forgot how much they were charging...

              Then again the GFCIs were significantly more expensive.

              Comment


                #8
                Re: An idiotic question about AC and shocks.

                One thing to remember is that GFCI's can usually protect other standar outlets that are connected to its load output. so installing it as the first outlet after the breaker will protect any others that are connected after it.
                Attached Files
                Last edited by R_J; 06-09-2018, 12:09 PM.

                Comment


                  #9
                  Re: An idiotic question about AC and shocks.

                  Originally posted by Spork Schivago View Post
                  AC still confuses me then. Let's look at two 120VAC's, 120 degrees apart. When one is +120VAC, the other is -120VAC, with a potential difference of 240VAC, right?
                  What you are talking about is split phase and it's 180° apart.
                  120° separation is used by three phase systems.
                  In the US that would give you √3x120v = 208v

                  Originally posted by Spork Schivago View Post
                  But doesn't the AC flow forwards and then backwards? Forwards, backwards, forwards, backwards? When I was trying to understand AC not too long ago (even three-phase stuff), I thought that's how it was explained to me...just happens so fast, we don't see or feel it.
                  The current flows.
                  It's better to think of it as a wave, it provides continuous motion.

                  Originally posted by Spork Schivago View Post
                  Where is the return path there? They say you don't need a neutral or ground to get the 240VAC. I know I don't use any neutral or ground when I'm testing my 240VAC outlets, but I do read 240VAC.....
                  You always need a return, it's always a neutral, ground is just for safety.
                  However in a two phase system the "neutral" will be the other wire in any given situation.

                  Originally posted by Spork Schivago View Post
                  So, touching the hot, so long as I'm not grounded (ie, wearing insulated shoes, not touching anything else) shouldn't hurt me? Even at the mains? Or is that enough current where it'll jump through the rubber soles on my shoes? I have 200-amp right now. I'm not going to do that, I'm just curious.
                  Current is irrelevant in this scenario, what matters is voltage, and your resistance with respect to it.
                  The bird on the power pole sees hundred of amperes under it's feet, yet it's alive.

                  Originally posted by Spork Schivago View Post
                  Finally, I wanted GFCI breakers, the actual electrical engineer we hired to do the work gave us some whole home lightning protector and whole home surge protector and I want to say he was claiming they were equivalent to the GFCIs, but I won't swear on that.
                  Then he did not know what he was speaking about, or you misunderstood.
                  A GFCI has nothing in common with a lighting or surge protector.

                  Originally posted by Spork Schivago View Post
                  Are GFCI breakers better than the tamper resistant receptacles, where you need to push equal pressure on both sides at once to not hit plastic? Or should we replace the receptacles she has access to and the breakers as well? She's now interested in receptacles and those little plastic plugs aren't worth a damn anymore. Thanks!
                  It has nothing with physical protection to do.
                  Following on from my answer above a GFCI is a device that monitors the current going out on a phase, making sure it comes back over the neutral.
                  If it does not it means it is leaking out somewhere else, for example into a child poking his fingers into an electrical outlet.
                  The GFCI then trips.
                  A GFCI is simply a coil with the hot and neutral wires passing through it.
                  For example the hot wire carries 10AH, it then follows that the neutral must carry 10AH back.
                  This nullifies any magnetiuc field in the coil, so it reads "0"
                  If any current goes back any other way than via the neutral then the coil will get energized tripping the breaker.
                  This works just as well in a two phase system without a neutral, because all the current must still come back to the source (transformer or generator) alternating via the other wire in any given point in time.
                  Normally in Europe a whole house GFCI breaker is installed in the panel, cutting the incoming mains in case of detected fault.
                  "The one who says it cannot be done should never interrupt the one who is doing it."

                  Comment


                    #10
                    Re: An idiotic question about AC and shocks.

                    eccerr0r's comment made me want to do the math here. Going to use my house as an example here. It has 3 non-wet location branches, with 5 sockets each (its a 60 amp panel, what do you expect?).
                    Locally, prices are as follows:
                    GFCI $12.88
                    Standard Comercial socket $1.99
                    Tamper resistant $4.97

                    For GFCI protected branches with standard sockets it would cost $62.52
                    For all tamper resistant it would cost $74.55

                    But, GFCI comes with the cost of nuisance tripping. Radio (CB, Ham, etc) operation for one. Another being old equipment like my Yamaha CR-640 that has a resistor from line to the chassis, and thus to ground via my ham shack ground radial, which has enough leakage to trip more sensitive GFCIs.

                    Personaly, i'm going to stay with my commercial grade, non-tamper resistant sockets clocking in at $29.85, but thats not the point here.
                    Last edited by goontron; 06-09-2018, 01:47 PM.
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                    Comment


                      #11
                      Re: An idiotic question about AC and shocks.

                      https://www.evaluationengineering.co...safety-testing
                      Attached Files
                      Last edited by budm; 06-09-2018, 03:43 PM.
                      Never stop learning
                      Basic LCD TV and Monitor troubleshooting guides.
                      http://www.badcaps.net/forum/showthr...956#post305956

                      Voltage Regulator (LDO) testing:
                      http://www.badcaps.net/forum/showthr...999#post300999

                      Inverter testing using old CFL:
                      http://www.badcaps.net/forum/showthr...er+testing+cfl

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                      TV Factory reset codes listing:
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                      Comment


                        #12
                        Re: An idiotic question about AC and shocks.

                        gfci testing
                        https://www.youtube.com/watch?v=GlM6PE2kKVY

                        Comment


                          #13
                          Re: An idiotic question about AC and shocks.

                          Yeah I recalled the Despot charging some ridiculous amount for the TR outlets and even more for GFCI. But they ("NEC drafters") claim that you can get TR outlets "cheap" because they were aware of new house construction prices -- but apparently they're wrong at least for the individual purchaser... (perhaps it's just the Despot, Low people, or A$$ milking the novelty of TR. Don't know for sure.)


                          Originally posted by stj View Post
                          AHH so YES, BOOM actually did one!
                          FSCK these TR, go GFCI!
                          Last edited by eccerr0r; 06-09-2018, 05:57 PM.

                          Comment


                            #14
                            Re: An idiotic question about AC and shocks.

                            That YT video is good, this one is also worth watching: https://www.youtube.com/watch?v=wR6g38Pxwog

                            On the point of cost for GFCI outlets, I understand from your comments in the US you commonly use a GFCI device for each outlet?
                            Here in Europe it's pretty much always a panel breaker.
                            For example one of the cheapest is this one on Elfa: 300-76-724
                            So around €35 but that's going to protect every outlet, it's a 3-phase GFCI...
                            Last edited by Per Hansson; 06-10-2018, 02:20 AM.
                            "The one who says it cannot be done should never interrupt the one who is doing it."

                            Comment


                              #15
                              Re: An idiotic question about AC and shocks.

                              No, as R_J pointed out up above, they are usually daisy chained.

                              You can get panel GFCI breakers, though I don't know how frequently they are used. I suspect it's convenience that GFCI outlets are used - if they get nuisance tripped, it's right there (unless it's daisy chained).

                              Comment


                                #16
                                Re: An idiotic question about AC and shocks.

                                Okay this actually isn't too bad from the despot:

                                https://www.homedepot.com/p/Leviton-...-WMP/100684043

                                Last checking this comes out to $1.09 (Leviton brand) each when purchased in 10s (and appears to be another 15-20% discount if you buy 50), which is comparable to the $0.68/each (Leviton brand) that you can buy in quantities of 1 for the traditional NEMA 5-15 receptacles.

                                Buying TR's one at a time costs $1.87 at the despot (Eaton brand)

                                GFCIs cost $13.97 one at a time (Leviton).

                                Comment


                                  #17
                                  Re: An idiotic question about AC and shocks.

                                  If it's an outlet thas going to get a lot of use, like on kitchen counter, I would check the higher quality/price ones. the 10 packs are ok for the rest

                                  Comment


                                    #18
                                    Re: An idiotic question about AC and shocks.

                                    Kitchens should be using GFCI's, plus they tend to be quite far off the floor -- though I wouldn't think of Leviton being of poor quality as they've been doing electrical stuff for years and years. Eaton I believe bought Cooper, but I've not had way too much experience with Cooper. It looks like they are also quite an old USA company, I just haven't had much experience with them.

                                    It's only outlets near the rugs that should at least have the TR's. Only "rugrats" would need protection afforded by TR's. Everyone else needs GFCI.
                                    Last edited by eccerr0r; 06-10-2018, 05:36 PM. Reason: word choice, this makes more sense; likely corgis won't be sticking screwdrivers into outlets

                                    Comment


                                      #19
                                      Re: An idiotic question about AC and shocks.

                                      You get shocked only if there's a path to ground and it's going through you.

                                      Tile on concrete is conductive, and is grounded if the concrete touches the ground. If you contact a voltage source (like an outlet or a buss bar in a breaker panel) and you're standing barefooted on something that's conductive and is grounded, you're going to get a shock.

                                      Rubber is insulative. That's why rubber-soled boots are usually mandatory when working on 3ph 480V industrial equipment. You can grab onto a LIVE 480V wire, wearing rubber-soled boots on dry ground, not touching anything conductive (except the wire), and you will be at the same voltage potential the wire is at. Just warn other people not to touch you or hand you anything.
                                      Don't buy those $10 PSU "specials". They fail, and they have taken whole computers with them.

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                                      Comment


                                        #20
                                        Re: An idiotic question about AC and shocks.

                                        i have been shocked a few times wearing rubber soled boots in a dry wooden shed . this was by touching one side of mains only . sometimes it activates the breaker .

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