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Extreme danger using Appliance module

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  • Extreme danger using Appliance module

    I have discovered a very dangerous situation with the AM12AU appliance. This appliance module is sold by all of the companies, Dick Smith, Tandy, Eon3 etc that has an australian three pin socket. What I have found is that these modules switch the Neutral pin and not the Active pin. This goes totally against how electricity is normally switched. The danger lies in the fact that say you had a light plugged into the device and decided to change the globe, even when you believed that power to the light was off, actually 240 volts will still be present in the light socket. I was so disturbed by this, I have contacted the office of the chief electrical inspector ( OCEI ). They have indicated this sounds very dangerous and have begun investigating this.

    All, be very carefully to fully unplug these modules from the mains supply before changing globes etc.

    Cheers

    Nick.

  • #2
    Hi Nick,
    As an electrician i find this very interesting, i wonder if the the lamp modules have the same problem.Let us all no if you hear back from the ocei,
    regards nick.

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    • #3
      Hi All,

      I have done further testing and found the the Tranciever module TM13AU does exactly the same thing. It also switches the Neutral leave a live active in the device.

      I have also checked the LM12AU module, and this one is a whole new ball game in it's self. This devices measures 240V no mater what you set the device to, i.e full on, Off, 30% dim.

      I am assuming that this device probably uses a Triac to do it's switching. From best guess without hooking the device up to a cro, is that I believe it works on current limiting rather than voltage. Either way, 240V all the time.

      As a past electrician myself ( no longer on the tools, swapped them for a laptop ), I am a little uncomfortable with the design of these modules hence bringing it to the attention of the OCEI. Also disturbing is the fact that the modules have a permit number from the same office.

      More to come as they investigate.

      Nick.

      Comment


      • #4
        nscott, I assume you do know that the modules must have some current flow in order to power the receiver and control the device itself, hence there is always some current flowing (leakage) through the load as long as the load is intact (ie. the light bulb is screwed in). Almost all plug-in X10 devices work this way because of the signalling on the power line. I do hope the devices are properly wired. Let us know what you find!
        |
        | - Gordon

        "I'm a Man, but I can change, if I have to, I guess." - Man's Prayer, Possum Lodge, The Red Green Show
        http://HiddenGemTech.com - http://MaineMusiciansExchange.org - http://www.WJZF.org

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        • #5
          Gordon, I think there is some confussion here.

          There are two sides to the plug in modules, 1) The supply side ( the pins ) 2) The Load side ( the socket ). The current draw that you talk about to power the module is on the supply side and has no relation to if there is a load or not on the plug in modules used here is australia.

          The test of this is that you can plug in an appliance module into a power point and then switch it on and off with no load lugged into it. You will hear the relay click. This is for plug in modules only.

          The range of hardwired two wire light switch do infact draw there power as you suggest through the load but that is a different case altogether and for another posting.

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          • #6
            I guess your modules are different than ours then. I measure line voltage across the load pins on my two- and three-prong appliance modules here... and they definitely have relays. I haven't pulled them apart to find out why.
            |
            | - Gordon

            "I'm a Man, but I can change, if I have to, I guess." - Man's Prayer, Possum Lodge, The Red Green Show
            http://HiddenGemTech.com - http://MaineMusiciansExchange.org - http://www.WJZF.org

            Comment


            • #7
              <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Gordon:
              I haven't pulled them apart to find out why. <HR></BLOCKQUOTE>It is from the circuit for local control. The appliance and lamp modules feeds 50 milliamps through the load so that it can detect when the load is being switched on locally.

              Comment


              • #8
                It's probably best not to assume these modules are off when performing electrical work anyway - a stray X10 command from a neighbourning installation or a command from a 'forgotten about' macro could turn a module on at any time.

                Also, the modules provide a voltage (with current limited) even when they are turned off, in order to facilitate 'auto-sense' which is where you can still use the manual switch of the lamp/appliance when the module is turned off upstream - switching the manual switch from off to on will be noticed by the module and it will turn on, a feature of these devices.

                In short - it should always be assumed that X10 modules are in 'standby' when they are turned off, don't assume they are safely isolated from the mains.

                Comment


                • #9
                  hawkeye,
                  just wondering what these modulrs are you are using that still turn on by the switch and do all these great things,
                  niko

                  Comment


                  • #10
                    Hawkeye,

                    I too like niko, am very interested to know what plug in modules do what you state above.

                    I have tested the modules that are listed above and they do not respond to the local switch on a load. when the aplliance module is off the voltage across active to neetral is 0 Volts.

                    I am guessing you are using a diferent version.

                    Lets us all know.

                    Thanks

                    Nick.

                    Comment


                    • #11
                      Both of these are USA:

                      The three-prong appliance modules are Radio Shack catalog number 61-2684B (same as X-10 model number AM466), and two-prong is X-10 model number AM486. Both have "local control" capability, meaning the use a sense current so that when you turn the appliance off-on, the module will sense it and automatically turn on.

                      See the description of "local control" on the X-10 site under the lamp module - the appliance modules I tested work the same way, but this info is not outlined in the appliance module description on the X-10 site:

                      http://www.x10.com/automation/firecr...m465_br1ab.htm
                      |
                      | - Gordon

                      "I'm a Man, but I can change, if I have to, I guess." - Man's Prayer, Possum Lodge, The Red Green Show
                      http://HiddenGemTech.com - http://MaineMusiciansExchange.org - http://www.WJZF.org

                      Comment


                      • #12
                        It is never a good practice to "trust" that the module is off. On the other hand, if that 220v wire is staying LIVE then there is a SERIOUS concern that needs addressed. Not only are you dealing with a live wire, but one with the ground totally disconnected. This would make the unlucky person touching it "the ground"!

                        Even here in the US I notice that on a standard lamp module allows some power to pass, even in the off state. I first noticed this when I hooked up a small tower fan to a lamp module. When the lights were turned off in the room, and the lamp module to the fan was turned off, I noticed the lights still glowing softly. Take a look at the picture below. I appoligaze for the quality, but to take a picture of the LED's, it had to be a fairly dark room, and not use the flash.

                        In the top picture, the module controlling the fan is "on". In the bottom it is supposedly completely off, NOT dimmed but I sent the off command twice just to make sure. HS also reports it as off and not in a dimmed state.

                        As you can see, there is still current going to the fan.

                        So, when working on anything plugged into ANY type of module, NEVER assume it is completely off, just play it safe and disconnect the device from its power source completely.
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