Smart Car of America Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
2,781 Posts
Discussion Starter #1
I am trying to replace a light switch that has broken. There were 3 wires connected. One hot/red. I probed that and the black wire and found 120V. Great! The red and other black should be 120V also, but no, it is in the mV range. Huh? I probed the two black wires, and got 103V! . I realize there is another switch to the entrance to the room, and this is probably why. Luckily I didn't fry myself, as replacing lights before I have had the unpleasant experience in the past.

There are many switches in the circuit breaker box, and I'm afraid it leaves a lot to be desired in labeling. I guess I could turn off the whole house so I don't accidentally fry myself? Any suggestions?

Thank you for reading!
 

·
Registered
Joined
·
1,870 Posts
Sounds like a two switch circuit, turns a light on/off from either switch. I'd have someone stand near the light being controlled as you progress turning off and on each circuit breaker until the light goes off, then the power for that circuit is deenergized and you can safely change the switch.
 

·
Registered
Joined
·
2,781 Posts
Discussion Starter #4
Thank you guys!!!

I was a CECS student for 3 years before I dropped out. AC wasn't something I understood much! Wasn't comfortable connecting two black wires, one hot and the other ground, to the same point, but that is how it was. (The switch literally broke, and basically fell apart!)

I was in a rush as my son had a birthday party to attend. I switched off I'm guessing 90 % of the switches. Left AC on basically. That took it out. I proceeded to replace the switch. No luck, light bulb still not working. Have bulbs on order for tomorrow!

Thanks again. AC shock was very painful, even though it didn't kill me...
 

·
Registered
Joined
·
2,781 Posts
Discussion Starter #5
So we have been living with this new switch for 9 - 10 months now, and have been left with a puzzle. (If anyone knows the answer please let me know, or if there's a place to read up on that I should read up on I'd appreciate that direction as well!)

So both switches work in this manner:

If the light is off, either one of the two will turn it on.

If the light is on, only the switch that was used to turn it on, turns it off. The other switch does nothing!

Been living with it, for this long.....

Thanks so much, if anyone can help?!
 

·
Registered
Joined
·
598 Posts
Google "three way switch problems."There are some youtube videos that will help you. I think you may have 2 wires on the replacement switch crossed.
 

·
Registered
Joined
·
218 Posts
I’m an EE. You’ve got some troubles. Some of the wiring is mixed up. A three-way switch should have one hot feeding the common of the first switch. The normally open and normally closed terminals on the first switch should be wired to the normally open and normally closed terminals on the second switch, one wire each. The common from the second switch is wired to the hot wire on the bulb. The neutral should be tied to the other side of the bulb and no place else.

If this is confusing, please don’t risk it. If not wired properly, house current can kill you or start a fire.

I hope this helps.
 

·
Registered
Joined
·
2,781 Posts
Discussion Starter #10
Hit the nail on the head Blackbelt! I had installed a two way switch to do the job of a three way switch. Made a run to the local Home Depot, got one, followed one of the online troubleshooting tips to find the common, attached the two other wires, and walla, 10 month issue solved!!!

Thanks all for the feedback! (I'm afraid this time I can pocket the electrician fee. I hate how service providers inflate rates just because of the city....)
 

·
Registered
Joined
·
2,781 Posts
Discussion Starter #11
vadsoom, thank you. I was typing I solved the issue just as you posted. (I actually studied EE CS and then dropped after 3 years of struggle. I have the utmost respect for EEs and CSs! My bachelor's is in Biology).

Anyways, I had purchased the wrong switch. I lucked out in that the switch I replaced is the one with the hot. So once I found the hot wire, I followed a troubleshooting post I found somewhere.

Yes, I have replaced lamps and outlets which have shocked me to varrying degrees. Luckily I'm still alive!!!
 

·
Registered
Joined
·
2,781 Posts
Discussion Starter #13 (Edited)
Uh oh, checking if my address is posted somewhere here!

(I was so sad when I watched the A/C repairman come, open the panel on the condenser unit, and tell me it was going to cost me $300 to replace the capacitor....)

(It turns out my aging father was the one who bought the switch. That's what I get for sending him to get one, back that long time ago...)
 

·
Registered
Joined
·
598 Posts
Glad i could point you in the right direction jzchen!
So what did he buy, a double pole switch?
I work in the electrical industry, so i have a little experience in these things. 3 ways can be confusing, but it seems you have gotten it under control.
Well done!
 

·
Registered
Joined
·
2,781 Posts
Discussion Starter #15
Glad i could point you in the right direction jzchen!

So what did he buy, a double pole switch?

I work in the electrical industry, so i have a little experience in these things. 3 ways can be confusing, but it seems you have gotten it under control.

Well done!


Yup, double pole switch! And me with my tiny knowledge tried to wire it up! My wife’s friend was over when we first noticed the phenomenon, and she just laughed!

Thanks again! It clearly states on the boxes how many poles you need for how many switches. When I looked up the three pole as you noted it immediately started to make sense....

If you guys are ever in the Southern California area please feel free to let me know...
 

·
Registered
Joined
·
598 Posts
Yup, double pole switch! And me with my tiny knowledge tried to wire it up! My wife’s friend was over when we first noticed the phenomenon, and she just laughed!

Thanks again! It clearly states on the boxes how many poles you need for how many switches. When I looked up the three pole as you noted it immediately started to make sense....

If you guys are ever in the Southern California area please feel free to let me know...
Thanks bud. I get there occasionally, as my sister lives in Mission Viejo
 
1 - 17 of 17 Posts
Top