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| Stupid voltage leak question |
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| ImpulsiveJames:
Ok, I know this is a dumb post right off the bat, but I'm hoping to minimize waste without any REAL danger. I bought an espresso machine awhile back and have been using it for a year or two. Recently I was barefoot on our garage cement floor and got a small tingle while touching certain metal parts of the machine while it was on.... The unit it grounded with a 3 prong plug. My multimeter is measuring 12v AC between the metal on the unit and the ground pin on a power strip. I understand water as electricity don't mix, but when you have a smaller voltage leak in the 12-20v range, is this lethal in the real world? Any advice or ways to find exactly where the leak is originating? |
| AVGresponding:
Voltages that low aren't normally hazardous, due to the internal resistance of the human body. People with certain medical conditions might be more vulnerable. I'm reluctant to say whether you have a fault or not, as I'm not a US sparky, and am not intimately familiar with the normal operation and failure modes of your systems. |
| Gregg:
Perhaps the ground wire isn’t connected internally; a dubious “feature” of many imported items; an easy check from the ground pin of the plug to the metal of the device with an ohm meter. Another possibility is a poor or missing ground at the wall receptacle. If voltage is present with it turned off; that is another story. :scared: |
| wraper:
--- Quote from: ImpulsiveJames on January 11, 2024, 04:17:11 pm ---My multimeter is measuring 12v AC between the metal on the unit and the ground pin on a power strip. --- End quote --- That metal could be totally insulated and the only reason you get that measurement is tiny leakage through tiny capacitance through air. Generally you get some voltage measurement even with free floating multimeter leads unless multimeter input resistance is relatively low. I suggest measuring current instead of voltage. |
| ejeffrey:
Check again with the dmm between the chassis and ground in current measurement mode. It's probably only a couple dozen microamps of current. If so, it's not a touch hazard as is. However, then do what Gregg says and check for continuity. If you unplug the device from the wall and measure continuity from the metal chassis and any other exposed metal parts (such as pipes, the boiler tank, etc) to the ground pin on the plug and it should show < 1 ohm. If not, those parts aren't grounded and the 3 pin plug is mostly just for show then. If you look around inside you might see if it goes anywhere. I don't know if there are specific rules for coffee makers, but I would think that at least the boiler and the pipes going in and out should be grounded since the heating element is at 120V and water is, as you say, conductive. |
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