Help me understand this wiring diagram, and maybe why the switches don't work

As a new question follow-up to a previous question, i have another learning experience in my attic.

A long time ago someone installed more switches and new plugs, to control a portable high-speed fan for house cooling.  I'd like to understand how this is supposed to work, why they did it like this, and why the plugs are "always on" regardless of any switch position combination

I suspect the installer wasn't that great because in the junction box there are no wire nuts, only electrical tape, and they reused a bare copper wire as hot, just wrapped itself in electrical tape too

In the diagram below, the PURPLE wire indicates the bare copper wrapped with tape to insulate itself

The overall goal is to replace the few remaining strands of Knob and Tube, but when i started opening up the floorboards and found this, i had to ask, what the heck is going on here.

I should specify, in Switch 1 black and purple are different connections not the same screw.  In Switch 3 however, red and black are on the same screw.

disclaimer - this is just to grow my own knowledge, i understand I'm not an electrician, should hire one if unsure, and we're all on the internet... nothing you say can or will be taken as professional instruction and no liability can ever be applied to you the respondents or EE.

switches, box, plugs, light
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Commonly there are three phase, neutral and ground.
Starting with the wall outlets, preduming standard/correct wiring. The right side is phase/hot.
Combining all the lines that are hot makes black, red, brown
Gray and purple are neutral.
Presumably s1 is the switch for the fan which is omitted from this diagram

Do you know the type of fan you have, the combination of s1 and s2 could be to deal with three positions to control the fan
1) off
2) auto temp in attic above turns fan on.
3) on, fan always on.

S3 as you pointed out is a straight forward light bulb control throu application of hot feed.
Oh, the reason for such wiring deals with distributing load accross multiple breakers.
Commonly breakers are 15 or 20 for lights and outlets.  To avoid popping breakers a room having outlets and lams are always on different circuits.
Hope the wiring complexity now makes more sense.
Gary CaseRetiredCommented:
I haven't seen knob and tube wiring in probably 40 years !!   [And that was in a very old home]

I tried to follow your connections, but there's not enough detail on exactly how the connections on the switches are configured to follow the connectivity.   Also, is the outlet ganged, or are the two outlets independently wired?

Finally, do you have an end goal for the re-wiring?  (other than just getting rid of the Knob & Tube wires)    i.e. do you want the outlet switched?       If cabling it isn't too much of an issue (hard to tell from your description), I'd be inclined to just rewire the whole thing -- put a switch in for the light;  possibly one for the outlet box (if desired); and completely eliminate any knob and tube remnants.
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Gary CaseRetiredCommented:
Arnold may have a point if you're omitted the additional wiring for the fan.    I assumed the fan was simply plugged in to the outlet, since you indicated it was "... a portable high-speed fan ..."
FocISAuthor Commented:
Hi guys

The old fan was probably 1940's, i remember seeing it once but when we moved in it never actually worked and i didnt see a need for it so recycled it.  pretty sure it had two speeds at least.

it would make sense about the different breakers but i can't see where the second breaker comes in, as far as i can tell there's ultimately only one hot lead and one common lead from the rest of the house

there's very little knob and tube left so if i can get away with keeping the fairly new white romex that is most of the diagram, it would be nice to ultimately have at least one switch control the outlet (and plug in some lights up there).  assuming the current romex in the diagram is either wired correctly or can be fixed by changing some around (and favoring wire nuts over electrical tape)

i can't tell why they have two switches but in every combination i've tried, the power remains on in both plugs.  the 3rd switch, for the ceiling light of course works fine...  and the first two switches for sure go straight to the junction box and straight to the wall plug (box to plug via separate runs)

after opening the outlet and looking at the wires, they're actually a little different, i have updated the picture below

the outlet isn't ganged, there is not the jumper that usually connects the two brass screws to each other, or the two silver screws to each other - it looks like this plug was never manufactured with those jumpers.  the bottom right silver screw is a pigtail to the ground screw, the ground screw has white from the jumper box and the pigtail.

updated plug wiring
FocISAuthor Commented:
i didnt mention this because i dont think it makes an electrical difference, but the two romex wires that run to the plug do have a bare ground wire in them just left hanging out in the plug and in the junction box (not screwed in, but clearly touching the metal cases) - now that i see they pigtailed common to ground, it may come into play now - although none of this ground runs back to the main source

the romex between the switches and junction box physically has a bare ground wire but it's deliberately taped black and not contacting the boxes, but this wire is tied to a screw at the switch, and wrapped into other wires in the junction

seems sketchy that the only thing preventing a short between common (metal boxes have to be charged with this seeing how the plug is) and that taped ground wire is the tape itself (and i can see the ground wire between the loosely applied tape)
The difficulty is that converting your diagram to an electrical representation would shed a betrr light.

Presumably the color codes for wires are maintain. Not s2 has a "reverse flow" I.e. When the fan is on it allows hit to flow down and the s1 off position will close the s2 on position
If the fan had two positions, s1 on speed one. S1 off s2 on speed 2.
It can also be a change in direction if the fan supports such behavior, s1 on air expelled/output from the attic, s1 off, s2 on air is sucked in to ventilate the attic.
FocISAuthor Commented:
i have limited knowledge and experience (which is why i'm asking) but to me it looks like:

1. the bottom plug always is energized because it gets it from the junction box, main feed
      - i understand common to ground in the box is dangerous, wonder why they did that

2. S1
      - black is always energized 'hot' by the red wire connection
      - purple is always energized by 'common' by the junction box
      - S1 must either energize or not energize hot to S2

3. S2
      - common hot terminal is switched by S1
      - what i dont get here is it either passes common down white or black to top plug
      - dont you need input and output both?  how is the top plug energized all the time?

is there some fiddling that can easily be done to make the plugs switch-controlled?

i'm considering running new romex directly from the breaker to this junction box instead of leeching the about-to-be-removed knob and tube, since i'll be in there anyway maybe i can take this chance to wire the switch/plug relationship properly
FocISAuthor Commented:
arnold - thanks for the reply

you have a very interesting point about a possible reverse direction of the fan - is there something in this wiring that would reverse the polarity or something?  when we moved in the fan only had one plug, but in any case it never actually spun, assuming the motor died a  long time ago

the color codes i chose in the diagram are accurate representations of the actual wire colors, except purple... purple indicates the physical wire is bare copper wrapped with electrical tape to shield it from the metal boxes

i always just assumed one switch was for the top plug (fan, for example) and the other switch was for some other light source or dehumidifier or whatever else might have been up there 40-50 years ago.   well the wiring looks like it might be early 1980s anyway, at least it's leviton :)

i guess in the end a good goal would be to have S1 control one plug on/off, and S2 control the other plug on/off, energizing the junction box directly with a new romex run from the breaker - re utilizing whatever i can between the switches/box and box/plugs
S2 on position (right top is depicted as hot)
Based on this presumably whatever it is connected to has HOT and just needs the neutral to close that circuit. I.e. If using the light/lamp example. It would appear as though

Both s1 and s2 effectively have two circuits while s3 has a single circuit.

In the off position in s1 and s2 it has neutral closed circuit.
when s2 is closed it lacks a neutral when s1 is on such that it appears as though it does not work.
s1 sends a hot to whatever it connects to, s1 in the off position with s2 in the on position effectively is sending a hot as well.
Is s1 a sensor I.e. Only actually activate the fan when the temperature in the attic hits a certain higher temperature?

You can confirm this: check whether the right top connector of s1 goes hot when s1 is on and when s1 is off and s2 is on.

You have to be careful with altering the mode of operation as it may result in a short condition if not careful.

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Gary CaseRetiredCommented:
"... i guess in the end a good goal would be to have S1 control one plug on/off, and S2 control the other plug on/off, energizing the junction box directly with a new romex run from the breaker - re utilizing whatever i can between the switches/box and box/plugs " ==>  In essence, you're saying just re-wire everything :-)

That's not a bad idea at all -- what's difficult for us to know is just how much of  a hassle it is to pull the new Romex.    An alternative is to disconnect EVERYTHING;  use a continuity tester to be CERTAIN you know which leads go where (and mark them); and then re-wire them.    This would limit how much new Romex you'd need to pull  [although I'd really try to pull one from the breaker and get rid of the knob & tube connections].
FocISAuthor Commented:
sorry for the lack of response here, i was sent out of town for a few weeks

i ended up banging my head too many times trying to figure out what the intention of the previous installer was, i dont see any function of switch2 and obviously the top plug never worked

i'm pulling new romex already up from the basement thru this half of the house - i was going to re-use what they had going for functionality but just said screw it and disconnected everything, put it back together with a new s1 for the top plug, new s2 for the bottom plug, and s3 still controls the ceiling light and an added plug on the opposite wall

the pile of k+t wire is growing little by little

the payoff in the end is free blown-in insulation in the exterior walls and attic floor, paid for by my gas company, who is paid back by government grants - once all the k+t is gone (well most of the k's and t's are staying but the wire will be gone)
Gary CaseRetiredCommented:
"... the payoff in the end is free blown-in insulation in the exterior walls and attic floor, paid for by my gas company ..."  ==>  That might be the financial payoff; but another very real "payoff" is you'll have SAFER wiring :-)
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