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Joined: Feb 2007
Posts: 65
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George,
It is renosteinke that is claiming these devices use the ground as a conductor, not me.
I agree that those devices should be using a neutral, not the ground, if they need a current path other than through the switched load. Perhaps renosteinke has found devices that "cheat" and use the ground instead. (In my opinion, such devices should not have a UL listing.) My experience is with electronics that have a neutral connection (cord-connected or hard-wired), so I am not very familiar with the workings of devices such as photocells, timers, etc. that use various "power stealing" methods. I agree that they should not use ground as a current path, but I've also seen enough poorly-made products to believe that there are some out there that do.
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Joined: Jan 2005
Posts: 5,445 Likes: 3
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When this issue of 'the ground as a make-do neutral' comes up, I think we run into two issues.
The first is the natural outrage of any properly trained sparky. "WE don't do that" and "that can't be right" are proper reactions.
Countering this is are the practices, even necessities, of electronic design. A 'dirty little secret' among the engineers and testing labs is that 'off' doesn't always really mean completely off, and that ground gets used for 'insignificant' amounts of current.
Which, of course, catches us on the horns of a dilemma: do we admit this, or even talk about it? We have to know about this in order to do our jobs. Yet, we don't want some uneducated noob to skim over a thread, and walk away thinking 'I just learned a neat new trick - I can't wait to use it - I don't really need that 4th wire to my new range after all!'
Getting back on track of this thread .... sometimes you really need a ground wire back to the panel; a GFCI might address safety concerns, but it will not create a ground path for you.
Perhaps we also need to recognize that nothing lasts forever. For example, my house was built in 1940, using the original version of Romex. That is, no ground wire. Maybe - just maybe - it's unrealistic to expect to continue limping into the 22nd century with an electrical system that is no longer adequate. Maybe there IS a time to knock it down, and start over!
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Joined: Jul 2004
Posts: 9,931 Likes: 34
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I did see an article in the IAEI rag many years ago about using the ground for some very small loads (Microamps) but I thought the U/L standard changed and they couldn't do that anymore. Virtually every "2 wire" timer or illuminated switch I have seen in recent years uses the load as the return path.
Greg Fretwell
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Joined: Jul 2004
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George I had you the first time. You are right, without 4 wires you can't properly ground an IG receptacle unless you just loop the EGC through the yoke to the IG terminal and at that point you could have saved $5 with a regular duplex. Of course regular readers here know that I think IG is snake oil, an opinion shared by the IBM physical planning manual.
Greg Fretwell
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Joined: Jan 2005
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Greg, what changed "a few years ago" was that a switch ould only say "off" IF it truly cut off the power. Illuminated switches - an example of a switch that doesn't completely cut off the power - can't SAY "OFF" if they power the lamp by letting a minor amount of current through.
(By way of contrast, if an illuminated switch did disconnect the power, using a neutral or ground path to allow the bulb to light, then they could say "OFF").
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Joined: Jul 2004
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That is the "off" and no current in the circuit rule. I thought there was another one about circuit current on the EGC.
Greg Fretwell
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Joined: Dec 2000
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Here's an example of an occupancy sensor that didn't have the EGC connected properly, and didn't operate properly at all. It depended on the mounting screws for grounding, instead of the EGC pigtail on the unit. The same model occupancy sensor had a neutral connection in the past, previous models to handle the load of the electronics.
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