6 Wires in Receptacle Box

I have a receptacle box which contains 6 bare ends. Three come in from the left, and three exit from the right. They are very old, cloth
insulated wire with no coloration (black). I can see that one pair of them used to have a white coating, and the the line side tests alright as neutral. It's the other wires I'm not sure about.
You can see a picture here: http://picasaweb.google.com/jbaker6953/Misc/photo?authkey=jlbInhkJdUQ#5144403298061863106
I have tested the voltage between all of them and between all of them and ground. Here are the results:
EA 121 EB 65 EC 101 ED 65 EF 101 E:Gnd 121V
I also performed a continuity test between all of them and all of them and ground. Here are the results:
CF < 1 Ohm CB = 16 Ohms A:Gnd < 1 Ohm
Any combinations left out were either 0 volts, or infinite resistance.
I want to wire these to a GFCI so that everything on the load side is protected. I cannot figure out what sort of wiring diagram would cause the readings I get, but then again I'm not an electrician. I know from various testing that E is line hot, and A is line neutral, F is load hot, and B is load neutral, but I can't figure out what role C and D play here. I would think they might be ground, but why only 101V between C and E with 65V between D and E? Can anyone help with the proper wiring in this case, or at least explain the readings I get?
Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jerry Baker wrote: > I have a receptacle box which contains 6 bare ends. Three come in from the left, and three exit from the right. They are very old, cloth insulated wire with no coloration (black). I can see that one pair of them used to have a white coating, and the the line side tests alright as neutral. It's the other wires I'm not sure about. > > You can see a picture here: > http://picasaweb.google.com/jbaker6953/Misc/photo?authkey=jlbInhkJdUQ#5144403298061863106 > > I have tested the voltage between all of them and between all of them and ground. Here are the results: > > EA 121 > EB 65 > EC 101 > ED 65 > EF 101 > E:Gnd 121V > > I also performed a continuity test between all of them and all of them and ground. Here are the results: > > CF < 1 Ohm > CB = 16 Ohms > A:Gnd < 1 Ohm > > Any combinations left out were either 0 volts, or infinite resistance. > > I want to wire these to a GFCI so that everything on the load side is protected. I cannot figure out what sort of wiring diagram would cause the readings I get, but then again I'm not an electrician. I know from various testing that E is line hot, and A is line neutral, F is load hot, and B is load neutral, but I can't figure out what role C and D play here. I would think they might be ground, but why only 101V between C and E with 65V between D and E? Can anyone help with the proper wiring in this case, or at least explain the readings I get? > > Thanks.
Hello, and I don't think voltage measurements on the load side with a reasonably high impedance voltmeter have a whole lot of meaning unless you know that the load(s) is connected (load power switches on). I'm also not sure what might be responsible for that 16 ohm value. Sounds like you have either a circuit breaker or switch box (minus those components). You may be measuring voltage drops across stray couplings internal the load(s) to ground (e.g. high impedance capacitance reactances). Another possibility could be motor windings that have faulted to ground. Keep in mind that SOME current, albeit a minute amount always has to flow through your voltmeter in order to obtain a measurement.
Having said all that and despite your claim that other line combinations showed 0 volts, Kirchoff's voltage law still has to be obeyed. In terms of voltage magnitudes of real and reactive voltages, and using your letter labels, we should have
EA^2 = EC^2 + AC^2 = EF^2 + AF^2 = AD^2 + ED^2
BC^2 = EC^2 + EB^2
BF^2 = EF^2 + EB^2
where EA = EF = BC = BF = 120V, EC = EF = AD = 101V, AC = AF = EB = ED = 65V
These relationships are more evident if you draw right triangle diagrams using the above labels and corresponding voltage magnitudes. This analysis is not intended to solve all your electrical wiring issues but to provide a basis for some of the readings that you obtained. Sincerely,
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jerry Baker wrote:

http://picasaweb.google.com/jbaker6953/Misc/photo?authkey=jlbInhkJdUQ#5144403298061863106

You have to *know* where the wires go to connect things safely. Do not connect them if you do not *know*.
Your measurement technique may lead to faulty readings. You must connect a load - say a 60 or 100 watt light bulb - across the wires to be measured to get a correct voltage reading.
Measurements may give you clues about how the wiring was connected, but connections *must not* be made based solely on measurements, if you want to be safe.
For more clues, consider: What was in the box before you opened it? What electrical things that used to work don't work now that the wires are not connected to anything? Which fuse or breaker kills power to E ? What else is it supposed to kill? With power killed to E, is there any other live wire in the box? You need to gather as much information as you can so that you can figure out exactly what connections to make.
If you can't figure it out, hire an electrician. That's obvious, but it has to be said - I don't want anything in my reply to lead you to a different conclusion.
Ed
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
| I have tested the voltage between all of them and between all of them | and ground. Here are the results: | | EA 121 | EB 65 | EC 101 | ED 65 | EF 101 | E:Gnd 121V
These look like you are getting phantom voltages from unconnected wires cpacitively coupled to other voltage sources. In order to really tell what the true voltage is, connect a load, such as a light bulb around 75 watts, to each pair being tested, then measure the voltage across the light bulb.
Also, all you did was compare everything to E. You need to compare all combinations just in case:
AB AC AD AE AF Ag BC BD BE BF Bg CD CE CF Cg DE DF Dg EF Eg Fg
I didn't look at the picture because I'm on a text console right now. Hopefully you have some color hints for each wire.
| I want to wire these to a GFCI so that everything on the load side is | protected. I cannot figure out what sort of wiring diagram would cause | the readings I get, but then again I'm not an electrician. I know from
One with capacitors in the line would cause such readings. Wires running beside each other are small capacitors.
| various testing that E is line hot, and A is line neutral, F is load | hot, and B is load neutral, but I can't figure out what role C and D | play here. I would think they might be ground, but why only 101V between | C and E with 65V between D and E? Can anyone help with the proper wiring | in this case, or at least explain the readings I get?
Capacitive coupling between wires can make one wire appear hot if the "load" is such a high impedance that it does not "drain" the voltage. A wire capacitively coupled between both a hot and neutral will read about half way between, relative to either. The light bulb is sufficient load to bring the voltages down to where they make sense.
Digital voltmeters have this problem because of their very high impedance. You can measure static charges with these things, if the static charge is not way too high for them.
Classic analog voltmeters are less affected by this because they use much more current to move the meter needle. Still, they can be affected in many cases. My analog microampmeter swings slightly when I touch the terminals.
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@ipal.net wrote:

I did measure all other combinations, but I get very small readings (like 0.1V). Only E has any voltage to ground, or to any other wire. What concerns me is the fact that every other wire in that outlet appears to be grounded. I thought perhaps the cloth might have worn off inside the conduit or something and shorted, but continuity testing between the conduit and the wires shows an open circuit.
Upon further examination of the house, it appears this receptacle might have been wired in the past to be controlled by three separate switches in the living room (one near each entrance). There is no ground wire as the system is relying on the conduit to be the ground (it's old).
The electrician came today and even he was stumped. He says he'll have to return with a meter to trace the wires through the circuit.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
| snipped-for-privacy@ipal.net wrote: |> These look like you are getting phantom voltages from unconnected wires |> cpacitively coupled to other voltage sources. In order to really tell |> what the true voltage is, connect a load, such as a light bulb around |> 75 watts, to each pair being tested, then measure the voltage across the |> light bulb. |> |> Also, all you did was compare everything to E. You need to compare all |> combinations just in case: |> |> AB AC AD AE AF Ag |> BC BD BE BF Bg |> CD CE CF Cg |> DE DF Dg |> EF Eg |> Fg | | I did measure all other combinations, but I get very small readings | (like 0.1V). Only E has any voltage to ground, or to any other wire. | What concerns me is the fact that every other wire in that outlet | appears to be grounded. I thought perhaps the cloth might have worn off | inside the conduit or something and shorted, but continuity testing | between the conduit and the wires shows an open circuit.
There could be disconnected wires, or wires connected to a switch (via a switch loop), or run to the box of an abandoned switch.
As others have suggested, you really need to (get to) know exactly where these wires go to. Once you find where that is, you can unhook wires and connect a battery to pairs at a time to identify which individual wire on one end matches which wire on the other end.
| Upon further examination of the house, it appears this receptacle might | have been wired in the past to be controlled by three separate switches | in the living room (one near each entrance). There is no ground wire as | the system is relying on the conduit to be the ground (it's old).
Lots of old wiring had no ground at all. They just had the neutral wire. But if this is a case where they were using the conduit as the neutral wire (called the "groundED" wire ... emphasis on "ED" because the real ground wire is called the "groundING" wire), you'll need to change that.
| The electrician came today and even he was stumped. He says he'll have | to return with a meter to trace the wires through the circuit.
At the very least he should have one in his car/truck.
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

My best wild assed guess is these are the middle of a 3 way switch loop (where a 4 way would go). If that is true you should have at least 2 other mystery boxes somewhere perhaps with switches in them. One might make "E" swap hot with another wire in that raceway.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

An electrician without a meter? I think I'd try a different electrician.
Raaaber Glover.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.