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Discussion Starter #1
Hey all,

some backstory: I've been working on rewiring my new home and have successfully updated the wiring to have dedicated 20a circuits for most of the appliances. Now the hard part begins of actually replacing all the runs for receptacles and lights in all the rooms. Before you ask, I feel it is necessary as the entire second and third floors as well as half the first are all on one circuit, and a portion of that circuit contains active knob and tube.

So, first major problem I hit: The attic (3rd floor) contains all new 14/2 romex wiring (less the 14/3 run for a three way switch in the stairwell). Both the lighting branch and receptacle branch are tied into this old knob and tube/cloth romex circuit. I figured out where the feed is for the lights, it actually ties into the switch box and connects to the new wiring running upstairs to the other switch properly. However, I cannot for the life of me figure out what is going on with the receptacles.

The attic has 6 duplex single gang receptacles. None have broken tabs, and all have open ground (due to being tied into k&t)

I'm going to lay out a diagram of their locations based on these numbers, the numbers also represent how many cables enter each receptacle box:
(top-down view on attic)
.............2................................1

.....1...............................................1

.............2...................................2


There is a stairwell in the middle, as well as a chimney on the wall at the top. I am 99% sure the lighting (3-way switches and fixture) are not on the run with the receptacles, they are on the same circuit however)

So my goal was to locate the main feeder wire so that I can locate where it's tied in, disconnect it, then run a new run of 14/2 to that location and tie it in within a j-box.
(if 12-2 is required here due to combination of lights/receptacles please let me know)

This is the issue though, I cannot locate the feeder for this run of receptacles, also, I cannot figure out a way they are run that makes it possible to only have one feeder. I keep ending up with one box needing three wires coming out of it (a third wire to be the feeder).

So I pulled a receptacle, disconnected all the wires spread them apart and turned the power back on. What I found is that my non-contact tester is reading higher voltage on the neutral than the hot, both hots (which were daisy-chained) still read voltage, though one makes the tester beep faster, and one other outlet tests no voltage with a plug in connecter but reads voltage with the non-contact. When turning off the breaker, I get no reading with either tester. This concerns me since my non-contact has never read voltage before where there was none.

So continuing trying to find the first in run I pulled another receptacle. Same deal, made 1 other outlet go out (a different one than the first) but everything still read voltage even with the wires being disconnected.

I am stumped, I've been wiring for a while but I've never run into anything like this. Is it possible there's two feeders? Three? I also can't see any older wiring tied into any boxes up there, have they possible joined the two loose in a wall or ceiling?

I appreciate the time and help
 

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Non contact testers can give false positive reading if there is power anywhere near them.
Best thing to do is disconnect power at certain receptacles and see what else goes off. Then you know that one is feeding the others.
It could be possible they tapped the K&T at three spots to feed the receptacles.
With number of cables in each box I would guess that you have three separate feeds. That is the only way you could possible get power with the info you gave. The boxes with 2 cable are feeding one of the other ones.
 

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Discussion Starter #3
Non contact testers can give false positive reading if there is power anywhere near them.
Best thing to do is disconnect power at certain receptacles and see what else goes off. Then you know that one is feeding the others.
It could be possible they tapped the K&T at three spots to feed the receptacles.
With number of cables in each box I would guess that you have three separate feeds. That is the only way you could possible get power with the info you gave. The boxes with 2 cable are feeding one of the other ones.
This is what I'm slowly figuring out I believe. Boy does this mean a lot more work for me... What are my options here do you think? I'd literally have to tear my entire house apart to find where they tied them in. Is it legal to cap off the old wiring in the existing boxes and then do a new run in front of it? How would I use a multi-meter in the boxes with two entry cables to figure out which is the feeder?
 

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Some times those non contact tester can be used as tracers.. Try waving it around one of the energized boxes and see it you can track which way the wires run. It might help if something is plugged into the receptacle and using current.

All energized wires must be terminated in a junction box.

To use a multimeter connect the two probes across the black and white wires from one cable and see if you have power. However digital muiltimeters can sometimes also give false readings. The meter for the job is a solenoid tester; sometimes called a wiggy. It applies a load to the circuit and eliminates phantom voltages.
 

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You have alot of work ahead in some pretty old wiring....

get a multimeter, which will serve continuity tests that you'll likely run into and a wiggy to test if you get strange V readings and you want to test for ghost voltage... or for a little more cost.... find a low impedance (LowZ) impedance multi-meter which basically does the same thing as a wiggy solenoid,
 

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Definitely get a decent multimeter. The non-contact testers are notoriously unreliable.

It may be easier to rewire the entire circuit. You can disconnect the current wiring at the panel. If the wires are not energized, you don't have to remove them.
 
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