Replacing exhaust fan/light switches - problems!

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  #1  
Old 06-05-06, 09:32 PM
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Exclamation Replacing exhaust fan/light switches - problems!

I live in TX and just replaced the useless heat lamp in my 70's house with bathroom exhaust fans instead. I found these nifty Leviton 6230M timers for the fans, so I bought two and two decora switches, intending to install them after the fans were in.

After the contractors spent about 8 hours installing the fans and fixing some old ducting, I went to work on the switches. In the master bathroom, the 2-gang switch box has 4 x 12/2 (plus ground) Nomex lines coming in, 2 at the bottom, and 2 at the top. I guess the bottom 2 are 1 each a feed/"daisy chain" out, and the top are 1 each fan/light. I wire-nutted the neutrals together with the white lead from the Leviton 6230, wire nutted the grounds together with the green lead from the 6230, wire nutted the 2 incoming blacks together with both the appropriate 6230 lead and a pigtail for the light switch. Wired the switch black lead out and the timer black Now nothing operates. Could it be that the adjacent GFCI outlet is feeding the circuit in such a way that caused the GFCI to trip when the circuit breaker was flipped back on?

To make matters worse, the hall bath has the same configuration PLUS a 12/3 conductor feeding in, which I am told is likely carrying 2 different breaker circuits to that box. Boy was I glad I poked around with my multimeter before grabbing things, because of course, one of the circuits in the 12/3 was still hot! I didn't mess with the hot red wire from the 12/3 that was wire nutted to a 12/2 black lead, I then wired the rest of the box in similar fashion to the above description, and the decora light switch works for that bathroom, but not the fan timer. Plus, from all the junk in that box and the rigid, old 12/2 wiring, I could hardly get it back together into the box, and the which is stripped out where the timer screws into it. Even if it did work at this point, it looks awful, bulged out and with a gap between the drywall and switchplage.

I work in a different city and had to leave to get up here before it was too late Sunday night, and I won't be home for probably 2 weeks before I can give it another shot. Needless to say, it was an extremely frustrating end to an unsuccessful DIY weekend, and I've been thinking about it a lot!

From what I've seen on this forum so far, I'll have some great ideas to try out before I get home to hammer out details. Ideas on gettings things to fit in the wall box better with the stiff, old 12/2 & 12/3 wiring, as well as maybe a better way to connect 4 or 5 12 gauge leads effectively, as I'm not sure the wire nuts can hold so many together tight. Thanks for reading through the boring details, and I appreciate your suggestions and time!
 
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  #2  
Old 06-06-06, 04:34 AM
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"I guess" is where you went wrong. While it is okay to guess what wires are what before you make changes, you need to verify they are, so that your guess is proved or disproved. Apparently you missed this step.

Your only choice at this point is to determine what all the wires are. Unfortunately your job will be harder since you probably don't know how things were wired before you started, and you probably didn't take detailed notes or draw (or take) pictures.

You should already know if the GFCI receptacle and the lights are on same circuit. You should know what is on every circuit in your house. You should also already know if any portions of the bathrooms are shared on a circuit.

Without detailed information about how many circuits power the bathrooms, and about what else is on any of the circuits, and about how old the house is, it would not be a good idea to make suggestions.

Please provide as much information as possible, answering the above questions and perhaps we will be able to proceed.
 
  #3  
Old 06-06-06, 07:12 AM
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Originally Posted by racraft
"I guess" is where you went wrong. While it is okay to guess what wires are what before you make changes, you need to verify they are, so that your guess is proved or disproved. Apparently you missed this step.

Your only choice at this point is to determine what all the wires are. Unfortunately your job will be harder since you probably don't know how things were wired before you started, and you probably didn't take detailed notes or draw (or take) pictures.

You should already know if the GFCI receptacle and the lights are on same circuit. You should know what is on every circuit in your house. You should also already know if any portions of the bathrooms are shared on a circuit.

Without detailed information about how many circuits power the bathrooms, and about what else is on any of the circuits, and about how old the house is, it would not be a good idea to make suggestions.

Please provide as much information as possible, answering the above questions and perhaps we will be able to proceed.
Thanks for the reply Bob. I was attempting to provide tons of details, but honestly, I don't know if there's much left to describe. As I said, the house is 70's construction (1974, to be exact). I've owned this house about 6 months. The 150A panel has about 20 breakers, with a whopping 6 of them labeled. The one that killed the master bath was labeled "Master bdrm lights".

I didn't know anything about MW circuits until reading on this forum, so of course after a light went out that was powered by the switch in question in the 2nd bathroom, I figured I had turned off that circuit as well (this was not the case, as the red wire in the 12/3 was still hot). I do need to make sure the MW circuits are on both A/B phases as to not create a condition that could overload the neutral. Otherwise, I haven't changed how the wiring was originally connected. I've simply attempted to connect the new switches as the old switches were connected, also tying in the neutral and ground leads to each fan timer (the fan timers require all 4 wires to be connected to function), all as described above.

I did not take detailed notes nor draw how things were connected, but these details are committed to memory if you have specific questions. Can I use my DMM to check the resistance between conductors in the GFCI and the switch box to verify that they are on the same circuit? Let me know what other details I can provide. Thanks for your suggestions.
 
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Old 06-06-06, 07:33 AM
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At some point, and now is the time, at least for the bathroom(s), you need to determine what is on each and every circuit. You need to know exactly what circuit breaker(s) to turn off when working on a circuit, and you need a complete list of items on each breaker if a circuit suddenly stops working. Search through this forum, you will find numerous situations of an "open neutral" or "open circuit" and someone had no idea where the problem might be.

The other reason to have all of this information well documented is that it could save your life.

Do not use the resistance function of your meter to try to map circuits. To do so requires that all loads be disconnected and that the wires be disconnected at the panel end as well.

The easiest way to map circuits, when everything is wired and working, is to use a second person. Turn on every light in the house. Also turn on something in every room (radio, TV, fan, etc.). Then turn off a single breaker. Have your partner tell you what is now off. Then with the breaker still turned off find out what else is turned off. Check nearby receptacles and don’t forget that another room may be on the same circuit. Keep going until you know what circuit breaker controls each and every light, receptacle and appliance in the house. Don’t forget hard-wired things like dishwasher, furnace, disposal, etc.

When a circuit is open and not working, you may need to use your DMM or a simple two wire tester with a built in light to check the wires. When using a DMM ignore reading other than zero and 120 or 240 (or close to them). DMMs suffer from phantom voltage, and you may see a reading of 70 volts which will only confuse you.

In your bathroom. Determine which wires bring in power. They will be one pair of wires from the same cable. You are probably correct that the other pair at the bottom of the junction box feeds additional loads elsewhere. As for the two top wires, the proper wiring depends on the wiring at the new fans. Try to remember what the wiring was before you replaced the heat lamps, and duplicate it.

In your posts, you have not mentioned how you wired the fan at all. How many wires are there, and how did you connect them?
 
  #5  
Old 06-06-06, 11:59 AM
ddr
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Originally Posted by racraft
The easiest way to map circuits, when everything is wired and working, is to use a second person. Turn on every light in the house. Also turn on something in every room (radio, TV, fan, etc.). Then turn off a single breaker. Have your partner tell you what is now off. Then with the breaker still turned off find out what else is turned off. Check nearby receptacles and donít forget that another room may be on the same circuit. Keep going until you know what circuit breaker controls each and every light, receptacle and appliance in the house. Donít forget hard-wired things like dishwasher, furnace, disposal, etc.
Just a quick addition/suggestion:

If you have a lamp or something plugged into a duplex outlet and it goes off when you flip a breaker, donít assume the entire outlet is on that breaker; check the upper and lower receptacles individually as the outlet may be wired with the top receptacle on one circuit and the bottom on another. It is also possible that an outlet has both receptacles on the same circuit, but only one of them is controlled by a wall switch. (Some localities allow these configurations, some donít.)

I find it easiest to get about 12 or so CHEAP nightlights -- no switches or light sensors, just plain, small, round ones that come in multipacks so you can plug one into each receptacle of an outlet and put them in all (or most) of the outlets in a room (you can also use them to fill the top/bottom of an outlet you already have a lamp, radio, clock, etc. plugged into and are easy to move around as needed). When you turn off the right breaker, youíll be able to see immediately if both receptacles are on the same circuit (both lights will go off) or if you have an outlet wired to more than one circuit (one light will stay on while the other goes off). To see if a wall switch controls all or only half an outlet, have the breaker on and turn the wall switch on and off. If both lights go out, the whole outlet is switched; if one light goes off while the other stays on, the outlet is half switched/half always hot.

While the nightlight thing is just a suggestion, knowing if both receptacles of an outlet are on the same circuit is a MUST.

Good luck.
 
  #6  
Old 06-06-06, 03:21 PM
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I agree, mapping my breaker box would be a good idea. Maybe my next three or four day weekend when I'm home for a decent length of time.

My DMM is a quality "true RMS" unit with frequency indication and datalogging, and I did see some voltages around 28V at the switch with the 5th line coming in. My a/c thermostat, doorbell, and some home security stuff run through that area, but I don't see how I could be reading class II circuitry on the big Romex. Maybe a "phantom voltage", as you said? I sure hope so.

The fans at both locations are fed with the line previously running to the heat lamp, which is a dedicated Romex 12/2 (w/ground). I may take the adjacent light cover off to verify it is wired the same, and also to test continuity on black conductors to rule out which is which coming in to the switch box.
 
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