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Posted: Wed May 17, 2006 9:49 pm
by BooMod
alright, I'll run a speaker cable from the water pipe in the basement that has a couple other big ground wires attached to it...

>>Turn on the light, and add in this wire to the ground return post as a full return ground

But I need a bit more clarification here. Add in this wire ..exactly where, exactly how? Is not what I am trying to test with this "real ground" going to actually be to connect my voltmeter to this new wire, and my other probe to the wires I am testing? Or does it have to be tied into the other groundwires in order for me to do this? The light itself has no groundwire...

Posted: Wed May 17, 2006 11:57 pm
by dyarker
Whoa! Low side switching? I didn't see that in the drawings.

In the pictorial the black lines feed the switches, except for the cable runs to the three-way switches. Normal, as long as black line means black wire which is hot, and light blue line means white wire which is neutral. The only problem in the pictorial is the narrow slot on the outlets is supposed to hot, and wide slot should be neutral. Hopefully BooMod just missed that detail when making the drawing.

On the hand drawn schematic, the voltages indicate the hot is being switched. The "C"s I don't know what they're supposed to mean.


The separate driven rod ground and small gauge wire Chris is talking about, doesn't get connected to anything except one meter lead. It is used as a reference to measure green wire ground, white wire neutral and black wire hot to.

(visitors, gotta' go)

Posted: Thu May 18, 2006 6:07 am
by BooMod
yes, the light blue is 'white" wire.
From the switch to the light (rather, light box to the switchbox) the white is marked with colored tape since it isn't neutral, but carries the power into the box to then tie to the red that goes to the common.

The second pic with the switch voltages is a SCHEMATIC of the three-way switches not a physical representation (so that no one says "Ah, the common is always on the same side as one of the terminals, but you show it as being the isolated terminal, so thats why its always messed up!" No, the diagrams are showing the Common on the three-way as unique, and the two travellers paired for clarity) C is for common.

Posted: Thu May 18, 2006 8:23 am
by BooMod
I guess that is a flaw in my diagram as-is, the image would indicate the black and white are on the opposite sides of the outlets from what they should be. But in reality, they are all correct, that was something I originally wanted to be sure of to make sure the polarity was right, and also have an outlet-tester that we ran on every outlet in the house that confirmed polarity was correct. I think in my oringinal room-based physical layout diagrams I made for myself, I had my outlets "upside down" as if viewed from the ceiling and when I then rearranged them to fit on a single sheet as a pathway-schematic I didn't think about the orientation of the image of the outlet.

Strictly an artwork issue here as lines into and out of the oulets weren't given more than a second of though to simply show their position in the path - but the polarity of their connections is correct if it conflicts with the diagram. Just imagine the outlet upside down instead.

Posted: Thu May 18, 2006 4:23 pm
by BooMod
Okay, in an attempt to be THOROUGH in making sure that the ground isn't an issue or determine if it was...

I emory-clothed a patch on my cold water pipe, and then clamped to it both the ground wire from some spare 14-2 romex and some 18 gauge speaker wire as well. With the common probe held to those wires, and measuring the voltage at the switchbox:

14g wire: metal box/groundwire: 0.1V Live wires: 121-122V, switch with CF bulb in place, attached to the terminal screw: 23-24V at the common-out.

Speakerwire: metalbox/groundwire: 0.1V Live wires: 121-122V. Switch with CF bulb in place, attached to terminal screw: 24V at common-out.

In other words, everything the same as it had been before when using the groundwire as ground. Grounded switchbox/wire at 0.1V wrt either wire attached to waterpipe.

So that factor no longer a factor.

Posted: Thu May 18, 2006 5:00 pm
by positronicle
--Edited by Positronicle--

Posted: Thu May 18, 2006 5:16 pm
by Chris Smith
If you checking for poor grounds,[bad voltage signal with a DVM] a loss at your ground at the circuit under test, Use your meter to your wire and witness the loss you mention and then attach the extra ground wire to your existing ground and see if this voltage loss disappears?

If this voltage loss does disappear, you have poor return wires or bad grounds.

When Ever I touch my body to one lead of a DVM, and the other to my computer plugged into a two wire system that has no actual [real] ground return, I get a buzz in my fingers if they are moist and a voltage reading of 20 plus volts at the return or ground wire,[or chassis] showing not all is returning to earth. This means, my returns are not returning all the power.

This is where I always add in a extra dedicated ground, [third pin] preferably five or six feet away from my work area.

Posted: Thu May 18, 2006 5:23 pm
by BooMod
I have accepted the CF bulb putting energy back into the empty system - I've go no problem with that anymore as a reality, but I am unable to wrap my mind around the wire having 1.5-2V when it is just the wire direct from the socket and 25V when I connect it to the switch.

If it is going to be the normal, everyone will see, scenario that the threeway switch will have 25V on one traveller and 120V on the other as part of its everyday usage, this is only a concern as far as the switches go. The 25V doesn't exist outside of the switches, which are both used to 120V through either wire anyways, or the 25V will be countered with a live 120V going through to the bulb.

So I guess there isn't a possibility of any damages within the circuit, in the end, which was my main reason for being concerned in the first place - is something wrong.

If the answer to why it is 1.5V at the wire until I touch the wire to the screw terminal, then rereading it isn't going to help me, and I will accept that as my own limitation. If the answer above is basically explaining just the fact that the wire itself can have that 1.5V on it, I accept that.

I accept the CF bulb supplying voltage upstream when there is no 120V going downstream, I'm still in lack of understanding the 2-->25 transformation.

Posted: Thu May 18, 2006 5:32 pm
by BooMod

I appreciate your efforts with trying to address the ground as an issue, but other than hearing over and over again that you have bad experience with grounds in your place and thus always keep a ground a few feet away from you at all times, I'm just not following what you're getting at?

You tell me to look at my voltage loss and then compare it under a different scenario? WHERE am I seeing a voltage LOSS in my system that I should be examining? Are you suggesting that I tie the ground wire coming from my copper water pipe to the groundwires in the circuitbox, then test the voltages, and if that "extra" ground helps to eliminate the 25V, then ... what?

Posted: Thu May 18, 2006 5:38 pm
by positronicle
--Edited by Positronicle--

Posted: Thu May 18, 2006 5:43 pm
by BooMod
On the chance that the interpretation was to add the ground to the ground in the switchbox, I did, and the end result...

no difference. none. Nothing different than using the groundwire in the box as my reference.

My wife is going to make me remove the wire running through the hallway and down the stairs and through the kitchen and more stairs and whatnot pretty soon, so I hope we can call that a completion of the ground testing?

Posted: Thu May 18, 2006 5:44 pm
by BooMod
Didn't see your post earlier. I can try

Posted: Thu May 18, 2006 5:54 pm
by BooMod

As predicted the bulb does hold a charge, I measured ~0.03V DC on it.

That still just confirms the bulb has energy in it, be it DC voltage, small, but I imagine that DC in an AC circuit gets to do lots of funky things: question is does the 0.03V DC theoretically yield my 1.5V Ac reading, or a 25V ac reading, or does the theory work for either and depending on the mass of copper wire it is attached to will result in the difference, such that if I had my 3-way switches placed at ends of 60 feet of wire instead of 10 feet, that 25Vac measurement would be intensified since the approximately 6 feet of single-14g wire between the bulb and switch had only 1.5-2V in the same case, yet with the switches, those wires become effectively 20 feet long plus the metal in the switch themselves?

Posted: Thu May 18, 2006 6:29 pm
by positronicle
--Edited by Positronicle--

Posted: Thu May 18, 2006 6:51 pm
by BooMod
thats quite a dynamic range.
I may have depleted some of the charge while dialling back my meter to an appropriate range, but did it twice (had my wife remove the hot bulb) to take my reading. I've repeated it just now twice more, and detected 0.3 and 0.1 as steady readings, though it flashed to -65 while it flickered over a range mostly around 0.3