Question - Outlet With 90 V Output?

Going through a crazy heat wave here in SoCal, and one of my tenants called to tell me that the electricity isn't on in some of his rooms. He turned on his portable AC unit that he has been using all summer and something may have happened.



Downstairs:The dining room light switch, downstairs light switch do not work. All outlets around them do work though, which is odd cause I would have thought they'd be on the same circuit.



Upstairs: The side bathroom light switch does not work, but outlets all work. In the master bedroom (where the AC unit is located), the master bathroom light switch does not work, nor does the master bedroom light switch. All of the outlets do not work either. I used my outlet tester and it gave me the hot/ground reversed lights. I think this means that the white/black wires are reversed on the outlets (has not changed recently).



I went over, checked all of the breakers. Switched them to off, then back on, did not fix the issue. All breakers stay in the on position without tripping, so no shorts?



Checked all GFCI's, hit test, then reset, did not solve the problem.



We unplugged everything from all outlets, and retried, but it didn't work.



I checked continuity between the main power lines, and the output of the circuit breakers, and all were fine. I did NOT check the voltages though, and will do so in the morning when I stop by again.



Is there anything else I should check?
      

I'm new to this site.  But would appreciate some troubleshooting.  I just renovated my kitchen, gutted and all, finished in the Fall.  I did not replace wiring to the dryer, nor tamper with it, to my knowledge.  We did have an electrician add a small fuse panel.  We did not add more appliances then before, added some lights, but mostly used the room to separate things out.  Had a mentor do the wiring, many years of experience, very tidy and careful work, though not electrician by trade.  We have a standard 200 amp box as far as i know.  The house is 100 years old, but the wiring isn't.



In October my mother in law heard a very loud bang.  The electric dryer had been running.  She smelled smoke.  At the dryer receptacle was molten plastic sprayed onto the wall, caused by overheating at that point, due to I don't know what.  I thought maybe I had knocked something loose in the receptacle when i was drywalling around it.  I can't remember now if the breaker had tripped.  The receptacle and plug were toast. 



I replaced the receptacle, I replaced the dryer cord, not the breaker.   The dryer worked fine until february, when it stopped heating.  I found a bad thermal fuse and replaced it, the very common two pronged white one. 



The dryer worked fine until early April when it stopped heating again.  I checked all the fuses/thermostats on the back and the heating element, as I had done the first time.  Nothing was bad.  I checked the voltage coming out of the wall, as I had done the first time, only this time I did it correctly and got a reading that told me to check the breaker in the panel, which had not thrown.  When I checked the voltage between the Nuetral Bus and the two terminals on the Dryer's 30 amp breaker I only got a good reading on one of them, telling me that the breaker was bad.  While at the box, i noticed that to the main breaker, from where the conduit comes into the box from outside, the nuetral wires are bare all the way up, no insulation, and at the terminal of the main breaker they appear to have all melted together, even a couple small pieces have melted off of the "bundle." 



Switched the range 50 amp breaker with the dryer, dryer worked fine, nothing was back fed either.  Bought a new 30 amp breaker for the dryer and installed it on Saturday.  Also on Saturday we were given a dryer, about 4 years old, same as ours, so i hooked it up and saved ours for a spare, which I deemed still good since it seemed the breaker was the issue.  New Dryer worked fine from saturday until today.  Now it won't turn on, though it didn't cut out mid load yesterday either.  The breaker did not trip.  I repeat, no tripped breaker.  I just checked the voltage at the wall and it seems to have that same problem where one side of the receptacle gets a reading of 120, and the other a reading of about 5.  The problem must be bigger than the breaker.  I am not an electrician, I am a welder.  I have gone as far as I could on my own.  Thank you.
      

Hi, I have a problem where if I turn off my light switch on one side of the  room, it turns off anything plugged into the electrical outlet on the  other side of the room. For some reason, they originally wired that  outlet on the same circuit as the light switch. I would like to wire the  outlet so that it does not switch off whenever you switch off the light  on the opposite wall.



How do I go about doing that? Thanks.



(p.s. There are just the basic three wires in the electrical outlet; black/white/bare copper ground).
      

Hey everyone - question about home wiring that was done when the house  was built about 20 years ago (which putting it delicately...is very  shoddy at best).  I'd like to think of myself as fairly knowledgeable in  basic home wiring...but this one has me baffled and I really hope  someone can help.



I am redoing a screened-in porch at the back of our house.  There is  currently a working outlet, and single-pole switch that turns on an  outside bug zapper, and a wire running coming into a second  switch...then leading into nothing in the ceiling (presumably for a  future ceiling fan / light install that was never completed).  I gutted  the entire porch and using one of those audible voltage testers,  discovered the wire than ran into the second switch / ceiling box did  NOT work. 



Not thinking much about it, I tried figuring out how the first switch  (to that outdoor bug zapper) was wired.  Most of the wiring for that  switch and the outlet I mentioned is behind the plywood sheathing of the  house...so it's near impossible to figure out where it goes.  Initially  it LOOKED like the power from the circuit panel came into the outlet  first...and then went out to the bug zapper switch.  (Why did I think  this?  The outlet had a B/W wire coming into it...and another B/W going  out back into the wall somewhere.  Tracing that wire along the basement  foundation best I could...it looked like it went right into the bug  zapper switch).  So wanting to completely eliminate the bug zapper  switch, I disconnected all of the wires that were connected to the  outlet to figure out which set was leading to it.



Here's where I got confused.  When I did this and re-tested voltage at  the outlet, one set of wires was live...and the other set was dead.  And  that makes perfect sense.  Yet the bug zapper switch STILL worked.  OK -  so my conclusion: the power for this bug zapper switch isn't coming  from the outlet.  No problem.  But just because I was near it, I decided  to also check that 2nd switch / ceiling wire combo...and what do you know - it was LIVE!



I got super excited it was working but then super baffled because I  didn't do anything to that ceiling wire at all.  In fact - all I did was  DISconnect 2 sets of wires at a nearby outlet. 



Confused but happy, I was ready to pack it in for the evening and  re-connected the incoming / outgoing wires back to the power outlet.   Flipped the circuit breaker on.  No issues.  BUT - now all of a sudden  the 2nd switch / ceiling wire that magically started working was NO  longer working - just like it hadn't been since I started this whole  process. 



Logic is telling me it's obviously got something to do with the outlet  wiring...since that's the only thing I messed with.  But why would the  ceiling wire all of a sudden become LIVE when the wires going into the  outlet were all disconnected?  It's certainly a first for me.  Can anyone help me figure this mystery out?  Thanks gang!
      

I only have one outlet in my living room and I need another one for sure. What are some ways I can do this?  There is not another outlet on the other side of the wall, we had a electrician come add a light with switch and he said something about closing off a line behind the switch box.  Is it possible to re-open that line? We also have a attic which I was told at homedepot is easy to do if you have another outlet in the next room you don't use. Any help is greatly appreciated!!
      

We just got a used hot tub.  It ran fine where we purchased it but since we got it home, it has not run.  We installed a new breaker for the hot tub and an GFCI outlet outside.  The hot tub inself has a GFCI installed on it.  If we plug it into the GFCI outlet it runs for a few seconds and either trips the circuit inside or the hot tub.  Is it necessary to have a GFCI outlet outisde if the hot tub has one?  We are thinking that this may be our problem..redundancy.  Can we install a regular outlet outside instead of the GFCI outlet?  When we plug it into a regular outlet it runs.  We want to make sure that this is safe before proceeding.
      

I have no power on the wiring on a GFCI outlet.  I tested the breaker and it has power.  I also tested all other GFCI outlets and they are working.  What could be my problem?
      

Well it's not really an outlet but just a junction box that has black, white and bare copper coming out.  I was told by someone before that this would be the end of the line for this circuit since the wires don't go any further from this box.   Its located in my attic just below the eve opening for an attic fan.  I checked the black and white wires a few years ago and measured 115 vac so I installed the attic fan and it was fine until this year.  No fan operation so I check for power and I'm measuring about 3 vac across the white and black wires now.  I disconnected the attic fan and measured the same 3 vac.  Test fan on another power sourch and it works.  Everything else on the circuit seems to be working.  Any ideas what might be happening here.  The attic fan really helps a lot and I'd like to get it working again.  If I need to provide more information please ask and I'll do my best.  Thanks for any help.
      

I have a wall outlet I exposed recently. It was meant originally to supply an in-wall air conditioner (long since removed). The outlet is clearly a 120V, 20A fixture. The romex supplying it, however, has been marked in indelible ink by the installer: "220" on both sides of the wire sheath. The wire is 12/2 with ground. What did he mean by this? Could this really a 220V (or 240V) receptacle? Is that possible, using 12/2 and a standard 120V outlet? How do I verify what I've got?



All I want to do is relocate the box and replace the fixture, but the 220 notation sort of threw me. Does anybody have an idea what's going on here?



I appreciate your help. I'm new here, so please try not to smack the rookie around too much.
      

I have two dimmable electronic transformers with 12 volt ac output. The track light system has two circuits with one common ground for the circuits. Can I wire one of the output wires from each transformer into the common ground of the track light system? I will be dimming each transformer with an electronic dimmer on the primary side.