2 commons and 1 hot ?

Reply

  #1  
Old 03-06-06, 02:37 PM
Member
Thread Starter
Join Date: Mar 2006
Posts: 8
2 commons and 1 hot ?

I have 2 commons and 1 hot going to a light fixture box outside. My new light fixture has 2 wires. How do I wire it? I am used to 1 hot 1 neutral and 1 ground. Please help!
 
Sponsored Links
  #2  
Old 03-06-06, 03:01 PM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
I doubt very much you have two commons and a hot. How did you determine this? What wires do you have and how are they connected. Describe ALL wires and how they are connected to anything. I am referring to the wiring BEFORE you removed the old fixture. I hope it's not too late for you to do that, meaning I hope that you KNOW how the old fixture was connected.

In general, you install a new fixture by duplicating the same connection scheme as the old fixture.
 
  #3  
Old 03-07-06, 12:14 PM
Member
Thread Starter
Join Date: Mar 2006
Posts: 8
2 commons and 1 hot

Hello racrift,
This is my 1st time using a forum and I am a little lost. Are you the one that replied to my post? I hope I have this right. If so Thank you. I removed a light and a separate photocell last year. I tried to hook a new one up and must not have had it right. I blew out the new light. I dropped it until this year. I do not know how it was hooked up correctly. So I tried to just hook up the new flood light without the photocell. I traced the wires to the breaker and of course turned it off. After hooking it up and turning the breaker on the light became very bright and went out. The light has only 2 wires. There are 2 wires coming in that both go to the ground or I thought it was the neutral bar in the breaker box. One wire goes to the breaker. I assumed this was hot. I hooked the hot to one wire on the light and one of the wires from the gruund [or neutral bar ) to the other wire on the light. I hooked the 3rd wire from the ground [or neutral bar] to the ground screw on the metal box that the light goes on. This undoubtably was wrong because it blew the light. I dont know if I blew the t-3 bulb or fried the fixture. Can you help me understand what I have? Thanks again for your help. I so appreciate it.
 
  #4  
Old 03-07-06, 12:47 PM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
Normal 120 volt house wiring (at least modern wiring) consists of three wires. A hot wire, a return wire (sometimes called a common or a neutral) and a ground wire. The neutral wire will be white, the ground will be bare or green, and the hot wire will be black, red, blue, or some other color, but not white or green.

The hot wire and the neutral are all that is needed to complete the circuit. The ground wire exists for safety reasons.

You made a mistake and hooked things up incorrectly. Connect the hot wire and the neutral wire to the new light and try again. If you still have trouble then you will have to investigate to figure out why.

However, I strongly suggest that you read a book or two on home wiring BEFORE you go any further. Any good book will give you basic knowledge on electricity and wiring that you apparently lack and will help you go further.
 
  #5  
Old 03-07-06, 04:45 PM
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 5,667
How many breakers does it take to turn off all the power to this box? I am thinking two breakers. You might have a multiwire circuit here. There is no way you should be able to hook it up and make the light go very bright and burn up unless you have 240 volts from something like a multiwire circuit.
 
  #6  
Old 03-07-06, 08:32 PM
Member
Thread Starter
Join Date: Mar 2006
Posts: 8
2 commons and 1 hot

There is only 1 breaker and I am familiar with the standard hot , neutral and ground. I have wired lights , plugs and switches before. But this has me confused. I will check again in the am to be sure and post again but I am certain that there was 2 wires that are hooked to the bar in the breaker box that I thought was a neutral bar and there is 1 wire that goes to a single breaker on 1 side. I'll post again after another look. Thanks again
 
  #7  
Old 03-08-06, 11:54 AM
Member
Thread Starter
Join Date: Mar 2006
Posts: 8
2 commons and 1 hot

Ok guys,

In the breaker box the white wire is run to the bar , the green wire is run to the same bar in the spot right beside the white wire, and the red wire is run to a single pole 20 amp D type breaker.I will get my ladder out this afternoon and remove the light fixture to make certain something did not come loose there and is touching ? There is an electric plug circuit that comes in to the breaker box that is wired identical and it is operating fine. I have not pulled the plug to see how it is wired at that end but it is the same setup in the breaker box. (white and green to the bar and hot to a single pole breaker)
 
  #8  
Old 03-08-06, 11:57 AM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
A green wire is a ground wire. A white wire is a neutral, or common. A red wire is a hot wire.

Therefor you have one ground, one common and one hot. You do not have two commons.
 
  #9  
Old 03-08-06, 02:56 PM
Member
Thread Starter
Join Date: Mar 2006
Posts: 8
I stand corrected

Ok . I understand now that I have 1 common, 1 ground and 1 hot. Why would 2 light fixtures have become very bright and burned up? [the common and the ground both hook to the same bar though , right?]
 
  #10  
Old 03-08-06, 02:59 PM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
I cannot explain why two light fixtured burned up. Perhaps you have a rpoblem on the circuit somewhere. Have you used an analog multimeter to check the voltage on the line? What else is on this circuit?

If this panel is the main panel in your house, then yes the grounds and neutrals connect to the same place.
 
  #11  
Old 03-08-06, 04:21 PM
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 5,667
Is this a cable or conduit? If it is cable you also have a black wire. This sounds like a multiwire circuit to me. Connecting between the black and red would give you 240 volts and burn up light almost instantly.
 
  #12  
Old 03-08-06, 05:36 PM
bolide's Avatar
Member
Join Date: Jan 2006
Location: PA
Posts: 1,909
Also connecting between the black or red and the white if the neutral is open upstream (closer to the panel), such as hooking only to the downstream white and omitting the upstream white.

This is why a pigtail should be used for the neutral in a multi-wire circuit.
 
  #13  
Old 03-08-06, 06:28 PM
Member
Thread Starter
Join Date: Mar 2006
Posts: 8
No other wires. It is as straight forward as it seems. This is why I have been at a loss. I may have figured it out today. It may just be a strange series of chance events. I took this fixture down to disect it today and try to find something...anything. The filament in the light was not burned or broken but....when I took out the t-3 bulb the white ceramic on the left side was cracked. I will buy another bulb and try it. Could it be I had it right and just had a series of really bizarre events back to back? Anything goes in the world of DIY. I'll post back as soon as I get the new bulb. Thanks again !
 
  #14  
Old 03-08-06, 06:54 PM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
Make sure that you aren't touching these bulbs with your hands. The oils on your fingers can cause the lights to instantly burn up.
 
  #15  
Old 03-08-06, 08:37 PM
Member
Thread Starter
Join Date: Mar 2006
Posts: 8
Thanks for the heads up. I was extremely careful with this one. I used a tshirt but I must have inadvertantly cracked the porcelin end cap on this one when installing. Since the filament was not burned in two and there was no visible damage...well it really threw me for a loop. Especially since this is the 3rd light fixture. What are the odds of that. I'll know more after trying a new bulb.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes