Lighting automation with 2 wire switch loop

[jbrukardt]

Ive hit a snag in my home automation plans in my old 1920s home.
 
all my ceiling lighting fixtures are switch loop device.
 
Power comes to the fan/light FIRST, then a 2 wire BX cable goes out to the switch.  
 
Do I have any options with this setup?
 
I can rewire to have power come up from the floor (14/2 ROMEX, neutral wire, all that) and then rewire the ceiling light, so the switch loop wire becomes the feeder wire.   But ill still be two wire only to the ceiling light.  The ceilings are plaster and lathe, and the fan is three joists over from the switch, its really really infeasible to pull new wire to the fan without destroying the house.  
 
Any ideas?

 

[tmbrown97]

UPB from Simply Automated will do the trick - you use a fixture module in the fixture base then a USR slave switch over the two wires that go back to the switch location... or you could repurpose the existing wires to the switch location as  hot and neutral and put a normal switch there too that transmits links to the fixture module.
 
Same should work with Z-Wave if that's your preferred technology.

 

[jbrukardt]

either way, i need a fixture module though it looks like, that really jacks up the price it would seem

 

[fcwilt]

Well seems to me you have a couple of options.
 
One is to forgo the ground wire to the ceiling fixture. From the point of view of day to day risk this is not too big of a deal as the fixtures are out of reach. But it likely violates code.
 
One approach that you could use, if going with UPB tech, is the UPB dimming modules that wire into the fixture and are controlled by a UPB controller (device with buttons but no dimmer circuitry).
 
One brand is listed below:
 
http://www.simply-automated.com/products/items/UFD-30_dimming_module.php
 
http://www.simply-automated.com/products/items/UCQT-40_led_status_controller.php
 
I used this approach in a similar situation.

 

[jbrukardt]

grrr, this just makes me want to get rid of that BX cable even more.  
 
Or solder a wire onto it at either end and use it as a ground (that was a joke... although it might work)

 

[pete_c]

Yup; BX is still a bit better than glass insulators and bare wires or cloth covered wires tacked to the walls.
 
Here in the midwest we have conduit.  I do and do not like it depending on my mood of the day.  Its been easy to add new circuits fishing wire in the conduit; but difficult to fit automated switches in the installed electrical boxes.
 
In Florida its all romex; which makes it hard to add new circuits; but the plastic boxes are a bit roomier for the automation switches.  With a new build there around 2000 the electricians did run 3 wire plus ground wire romex to literally every electrical box; which made my DIY automation stuff easier.  The contractor did utilize firebreaks in all of the walls; which is something I did see in the older first home we had which was built sometime in the 1950's.
 
Recently did update many UPB switches to multitoggle / dual load switches doing the remote thing on a lot of the UPB switches as mentioned above.

 

[RAL]

Does your BX cable contain an internal flexible metal tape along with the black and white wires?  This would be a thin aluminum or copper tape, as in the picture below.  If so, I believe that in many jurisdictions it is acceptable to use the BX as your ground conductor, so long as it is properly bonded at the end points. 
 

 

[jbrukardt]

sure doesnt, its pre-1950s bx, which means cloth insulation and two wire only with the wire shealth as "ground"

 

[jbrukardt]

i suppose i could yank on it really hard and see if its secured or not.  I bet it is though, and that could end badly

 

[pete_c]

Here in the midwest I have put in new conduit and in Florida new romex in walls and ceilings.  I have done this with a concurrent redecorating thing when my wife wants new colors or changing a room.  Ceilings are harder but I have cut small holes and have been able to pass conduit and or LV cabling on the second floor ceiling. Its been done before painting the room.  The difficult but not impossible pieces have been taking the wires or conduit down a wall drilling a hole in the top 2X4 header.  I added some (6 to the existing 4 outlets for 10 double boxes) more electrical outlets in the garage doing similiar in the walls.  Ran new circuit wires box to box to ceiling to wall and down to the basement in little baby steps.  Easy runs and little pipe bending. The second floor ceilings here though have about 1.5 feet of empty space with insulation; which makes it a bit easier. Yup; over the last 10 years have doubled the number of circuit breakers here getting granular a bit with additional circuits.
 
In Florida  for whatever reason one side leading to the master bedroom hallway had no lighting (missed it on the drawings).  That said the attic entrance was some 15 feet away.  I was able to crawl over the hallway and put a can in the ceiling and a new wall switch in; which worked out but a bit time consuming; mostly climbing on rafters in the attic; clearing a path of insulation and laying one small sheet of plywood to be able to work on it easier.   The romex was way easier to run than conduit and the set up was plug n play.

 

[jbrukardt]

i guess i should provide a bit of context. 
 
This is the first floor ceilings (second floor are actually a cakewalk, fully open attic).    They have at least an inch of plaster, and lathe on them on the bottom side, and hard as nails old growth fir subfloor on the topside, with hardwood floors on top of that, and in some places, carpet on top of that.
 
Oh, and theyre filled with plaster debris from 100 years of house. 

 

[tmbrown97]

Well, the fixture module with a slave will cost about $15 more than a standard switch, at least with UPB, and it'll work with your 2 wires but without a working indicator light.  But it'll work like an extension of the fixture module, meaning tapping the switch to get into setup mode activates setup mode on the fixture module; and it's a single device to program.  Sounds a bit easier than pulling new wire or violating code or doing anything risky.  Of course new wire would be best but it sounds daunting unless you start with what you can today, then as the opportunity comes up cut a few holes and fish new wire.