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Bone-headed wiring


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Just rung-out my living-room ceiling wiring.


6 cans, 4 arrange as a square around the room, 2 kinda diagonal across one corner.


A circuit was added from the  panel for these.


Originally, apparently was a single-gang switch in the LR controlling an outlet. It was changed to a 3-gang.


They added a 4-wire cable from the switch box to a junction box above the ceiling (accessible via access panel for A/C). The junction box was once adhesive-d to something, but currently just sits on top of the drywall. Great, it will knock the fireman cold!


3 Maestro dimmers in the box. I dunno why 3, but I can guess. The 3-gang has hot, neutral, ground from the main LR circuit (separate from ceiling lamp circuit) (which goes from there to various LR outlets), the 4-wire to the junction box, a red mystery wire to somewhere, and a couple extra mystery wires to the same armoured cable exit as the wires going to the ceiling junction. Either those mystery wires end inside of the armor (scary!) or they go somewhere else (splitter fitting? Can't see the outside of this box). Mystery wires weren't capped, just cut-off.


When I moved in, they said "couldn't get the 3rd dimmer to work, don't know what it's for."


Pretty sure some idiot used it to dim the controlled wall outlet. I will find the previously-controlled outlet as I replace the lousy sparking outlets.


Anyway, somebody couldn't count. The first two dimmers were, indeed controlling the two groupings of 4 and 2 cans. The 2 was flakey though. How do you do that on 4 wires from the ceiling junction to the wall switch box? Why, borrow the green to use for a load, that's how! No coding, but even coding is not legal. You can't use green for anything but equipment ground, period. They needed 5 wires.


So, the dimmers were equipment-grounded to a different circuit. Which happens to be on a different phase. Of a system wired off of 3-phase.


Wish I had taken a photo BEFORE taking the dimmers out to prove it, but I think that one of the dimmers borrowed either hot or neutral from the other circuit.


My first clue was taking random measurements in the wall switch box and finding 75 volts.... Pretty sure the last paragraph is true, because the two cans in the corner were dim and flakey, LOL.


It's only a few feet, I wonder if I can push a fifth wire through? Have to check the diameter of the whip, to see if loading with another conductor is permitted.


I don't really need the groups of cans controlled separately. For now, I am going to put all 6 on an Insteon dimmer and restore a proper equipment ground. I could use a mini or micro dimmer, or even a micro dimmer in each can, which would be more functional. (Removed the lamp from the one right over the sofa, it hits you in the face.) They all have LED screw-in conversions, so easy to just wire the micros into the conversion wiring. That would wait for the next 20%+ sale...

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Just reviewed the photos that I DID have.  There were two mystery wires. White and red. I've subsequently rung-out the white mystery wire to be the neutral from the ceiling junction. Unused in the wall switch box. OK, legit, there was no need. But now I need for the Insteon dimmer. They used the green for the load. I guess it would be equally wrong to code the white as load, right? You can code black for load, but not white. But seems less bad than green!


Glad I took the time to ring it out, as I likely would have used the neutral from the wrong circuit for the Insteon dimmer.

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How have you determined that your wiring is 3-phase? If you have flexible conduit (also called Greenfield), then you'll have to pull out the existing wires and pull in new wires if you want one or more conductors added. If you have armored cable (also know as BX), then you'll have to replace it or add another cable. Post the pictures you do have.


BTW, any color wire can be used for any purpose as long as it is identified as such, usually with "phasing" tape.

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How have you determined that your wiring is 3-phase? If you have flexible conduit (also called Greenfield), then you'll have to pull out the existing wires and pull in new wires if you want one or more conductors added. If you have armored cable (also know as BX), then you'll have to replace it or add another cable. Post the pictures you do have.


BTW, any color wire can be used for any purpose as long as it is identified as such, usually with "phasing" tape.


1. 208 volts at the range.


2. Confirmation with electric contractor who did 1999 installation, as well as power company.


Each apartment gets 2 phases, they distribute the load throughout the building where each apartment gets 2 of 3 phases.


Checked N.E.C. and by my read, green wire can NEVER be used for anything but equipment ground, and white can NEVER be used for anything except neutral. Not even if coded.


Also, just checked about the equipment grounds, as they are metal boxes and and two circuits in same switch box. All the equipment grounds should be brought together in the switch box.


I will post a picture. It is "BX style" but I know that's not what's really used now, right? Current would be "MC", BX is older. I will post a picture, as it will be good to know just what it is.

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I wasn't aware that you lived in an apartment building (where 3-phase is common). BX is still common in many cities. MC armored cable includes a green ground wire, BX does not. You are correct, green cannot be used for other than ground, but white can when appropriately identified.


Were the label in the image already in place? If so, list them (including the wire color).

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It is BX, then. There is no green ground wire incorporated. There is a separate green wire in every cable.


LOL it was probably knob-in-tube or something equally awful before they did the 1999 renovation. The building was built in 1927.


No, I added the labels after ringing it out. The blue tape was there. It only identified the BX cables for:


- "power" feeder from the circuit breaker box

- "switches" cable to switch box on wall

- "cans" 4 can lamps

- "art" 2 more can lamps


The cans were not put in in 1999, as several people have commented "oh, someone put in can lamps, nice". I put in nice 4" LED retrofits that come with screw-in adapter.


It's bizarre that the lamps are strung 4 and 2 and brought back to the junction, but then they didn't run enough wires to the switch box to control them separately without borrowing the green.


Oh, the green also wasn't bonded to the switch box, but of course installed devices would accomplish that. (The green was bonded to the box above the ceiling, though.)


I have a KeypadLinc with the 6 lamps as the load for now. The lamp that was flickering has stopped being flakey. I don't think now it was the odd wiring, as certain now they didn't do anything strange with the neutral. Think it was just one of the old beat-up Maestro dimmers. I actually only have one LED retrofit installed in the 2-cans, and perhaps the Maestro couldn't deal with the small load.


On the 208V, was pleasantly surprised by the range.  I feared I might not be able to cook an omelet or use a wok. The oven heats up much slower than at previous place. But it is hobbled by both being the newer hidden element design AND running on 208 not 240. (It is rated for 208, but of course at lower KW.) But the cooktop - oh, my! It's a GE where one of the burners is a 3-ring burner with "power boil" feature. Heated pan for an omelet in 2 minutes flat. (I measure surface temperature when I cook an omelet - right temperature with stainless not non-stick, and ghee - and never sticks. A little metal polish keeps it so...) Honestly I stumbled across it at the Sears Outlet, and didn't know I had 208V when I bought it. I thought "that's a nice feature" but wasn't shopping for that. That burner is a life-saver with 208V. Crank the thing up all the way on 240, and I imagine it would destroy clad cookware fast, though!


Next Smarthome sale I will get 6 micro-dimmers for the cans and take them off of the KPL. Other two positions will probably control new tracks. One of the tracks can use the load wire from the switch box freed-up by using the micro-dimmers, as it will have halogens, and wired out of that above-ceiling junction. Other track will be LED can a mini (not micro) dimmer can handle it with a Switchlinc used only as controller.


I did take a photo of the "whoa!" moment. See below. And, yes, that's a burn mark too.











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Another angle.


This one shows the uncapped mystery wire (which I speculate is a load wire that goes to an outlet I haven't yet replaced - will find it tomorrow).


And - eeek! - the uncapped neutral from the junction above the ceiling. Could be worse, it could have been the hot.


Of course that neutral now goes to the KPL.


Yes, I cleaned the Chinese Drywall dust out of the box. Actually, 1999 is a few years before that, but I wouldn't put it past the developer to have gotten ahead of the crowd. The wiring shows all the symptoms (this box is way better than most, some have BLACK copper) I'm gonna see if I can get the drywall tested affordably.


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The green wire is one of independent wires inside of the armor. It is not a wire that is integral to the armor. 


Maybe we are saying the same thing, but backwards, LOL. 


I read there is MC and MC Lite. This would be MC Lite if it's MC-type.


Maybe this is just a brand name?




MC Lite® is a traditional Type MC cable containing one or more copper grounding conductors; the armor is not an equipment grounding means



That's what I've got.

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MC cables are aluminum and include a ground wire. The armor is not approved to be a ground connection. BX is steel and never includes a ground wire. The armor functions as a ground connection.

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The cabling includes an insulated green ground where. There is no bare bonding wire.


The wiring was probably reasonably safe, but did not meet code. 


Last thing I finally noticed is that one of the saddle-style clamps on the junction box above the ceiling was installed with a screw that was too long, and since the screw bottomed-out, the saddle did not perform the function of keeping the cable from being pulled out from the box. 


I found the correct-length screw. It was one of the screws holding the box cover on. Yes, the too-long screw was exactly the same length as the OTHER box-cover screw. Imagine that! ;)


I shudder to think about the clamps that I CANNOT see! Hopefully, next earthquake doesn't cause enough movement to pull cables out of boxes.

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