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An electrician did something wrong and now my exterior garage light doesn't work

An electrician did something wrong and now my exterior garage light doesn't work

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  #1  
Old 04-29-11, 03:33 PM
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An electrician did something wrong and now my exterior garage light doesn't work

Hi all,

I hired an electrician to do a simple job in my garage: add a circuit, some outlet boxes, and a double switch to switch on/off two additional outlet boxes. I have an exterior garage light that is hooked up to a photosensor. That night, when the sun went down and the electrician was gone, the light didn't come on.

Long story short, this guy was a real jerk and was not respectful to me or my fiancée. In a normal situation, I would have this guy come back and fix it but my fiancée doesn't want him in our home again.

I am a very hands-on DIY type of guy. I wanted to take on this project myself, but I've never tackled adding on a new circuit before and we needed to get this project done.

I am trying to troubleshoot the issue. I have an electrical tester and this is what I have done and what I know so far:
  1. I tried a new light bulb. Tried another new light bulb and checked the continuity of the light bulbs. The light bulbs were fine.
  2. I live in North Chicagoland. Code used to require conduit for everything but not anymore. This new work was still done in conduit.
  3. Checked the voltage feeding the photosensor. It was 120v.
  4. Checked the voltage coming out of the photosensor and going to the light fixture. It was 120v.
  5. Checked the continuity of the photosensor. That was good.
  6. Tried a new photosensor. That didn't solve the problem.
  7. Tried a different light fixture. That didn't solve the problem.
  8. Bypassed the photosensor. That didn't work.
  9. Tried to check every connection/wirenut on this circuit to see that they were properly connected. I can't say I've checked 100% of them.


I'm going to troubleshoot some more tonight. Does anyone have any suggestions on what to do? Maybe a test I am unaware of?
 

Last edited by cubbiesfan; 04-29-11 at 04:03 PM.
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  #2  
Old 04-29-11, 03:47 PM
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What kind of tester did you use: DMM? Analog meter? Non-contact? Neon? Wiggy?

Were you measuring hot to neutral or hot to ground?
 
  #3  
Old 04-29-11, 03:59 PM
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Originally Posted by ArgMeMatey View Post
What kind of tester did you use: DMM? Analog meter? Non-contact? Neon? Wiggy?

Were you measuring hot to neutral or hot to ground?
I used a digital multimeter to measure hot to ground and used the continuity function to check the sensors, lightbulbs, etc.

I did buy a non-contact voltage detector just to see if it would help speed up the process of checking the connections without having to disconnect every wirenut but I'm doubting the accuracy of the tool.

I updated the original post to clean up some of the wording. FYI, just in case something I wrote didn't make sense, it might now.
 
  #4  
Old 04-29-11, 04:28 PM
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Originally Posted by cubbiesfan View Post
I used a digital multimeter to measure hot to ground and used the continuity function to check the sensors, lightbulbs, etc.
Try checking hot to neutral.

If there is a GFCI upstream, is is possible that it's hooked up backwards? That is, line to load side, or hot and neutral reversed? I haven't really thought that through but I'm thinking there might be some permutation that would let hot through and interrupt the neutral.
 
  #5  
Old 04-29-11, 04:41 PM
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Originally Posted by ArgMeMatey View Post
Try checking hot to neutral.

If there is a GFCI upstream, is is possible that it's hooked up backwards? That is, line to load side, or hot and neutral reversed? I haven't really thought that through but I'm thinking there might be some permutation that would let hot through and interrupt the neutral.
I will have to double check when I get home, but I believe I did try hot to neutral and I believe the meter didn't do anything. What should the meter read? I had the meter on the same function as I did when I tested hot/ground. (I'm not an expert with the DMM yet )

There is a GFCI upstream that is not supposed to be on the same circuit, but it may very well be. I did check to see if the GFCI was triggered and therefore the potential problem, but I reset/tested the GFCI and nothing changed. I also checked the GFCI to see if it was powered and both sockets successfully powered a lamp plugged into them.

I'm leaving work now and will check the wiring connections on the GFCI as soon as I get home.

Thanks so much for taking the time to help me! I really appreciate it.
 
  #6  
Old 04-29-11, 08:52 PM
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If your getting 120v at the light fixture between neutral and hot the light should work. Did your check the light bulbs?
 
  #7  
Old 04-29-11, 09:27 PM
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Tolyn Ironhand
If your getting 120v at the light fixture between neutral and hot the light should work. Did your check the light bulbs?
And to answer your question,
I used a digital multimeter to measure hot to ground and used the continuity function to check the sensors, lightbulbs, etc.

I tried a new light bulb. Tried another new light bulb and checked the continuity of the light bulbs. The light bulbs were fine.
Also, you could always send your fiance out with friends and sneak the electrician in and just tell her you fixed it or somethin'
 
  #8  
Old 04-29-11, 11:19 PM
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Originally Posted by Tolyn Ironhand View Post
If your getting 120v at the light fixture between neutral and hot the light should work. Did your check the light bulbs?
Well, I was getting 120v between hot and ground but nothing between hot and neutral. I checked hot and neutral at a known working connection and was getting 120v.

I traced back the wiring to each junction box and found the problem. The neutral from the light was not wired into the neutrals going back to the panel. The neutral was connected to another neutral wire coming from an unknown source. I'm pretty certain it was another another neutral on the circuit that was was causing a problem I hadn't discovered yet.

I connected the two neutrals to the other neutrals and the circuit was completed. The light started working.

Now I just need to connect the neutrals more appropriately. There's roughly 6, 12 gauge wires connected with a red wirenut. I'm thinking a couple pigtailed connections will do the trick.

If something doesn't sound right, please feel free to correct me. Thanks to you all for taking the time to help me!
 
  #9  
Old 04-30-11, 12:15 AM
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Be sure all the neutrals are for the same circuit. Neutrals from different circuits can't be connected together.
 
  #10  
Old 04-30-11, 01:20 AM
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Originally Posted by ray2047 View Post
Be sure all the neutrals are for the same circuit. Neutrals from different circuits can't be connected together.
Hrmmm.. When the electrician was here, he did say that 2 circuits could share the same neutral. There is at most, 2 circuits sharing the neutral. I don't know if he added a second neutral or if he shared the neutral.

Now I'm a bit worried that something is wrong.
 
  #11  
Old 04-30-11, 06:12 AM
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Originally Posted by cubbiesfan View Post
Hrmmm.. When the electrician was here, he did say that 2 circuits could share the same neutral. There is at most, 2 circuits sharing the neutral. I don't know if he added a second neutral or if he shared the neutral.

Now I'm a bit worried that something is wrong.
Don't be. He is right. Two circuits may share one neutral in a multiwire circuit which I'm guessing he ran. Just make sure the circuits are on different phases. The breaker(s) should be next to each other one above the other.

Well, I was getting 120v between hot and ground but nothing between hot and neutral. I checked hot and neutral at a known working connection and was getting 120v.
120 volts between hot and and ground at the fixture but not between hot and neutral indicates an open neutral. Trace the neutral back until you find the bad splice.

Sorry about the light bulb thing. I was a bit tired and missed that one.
 
  #12  
Old 04-30-11, 06:42 AM
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Just to clarify I was talking about two separate neutrals from two circuits. They can not be tied together. In a multiwire circuit you do not have two neutrals tied together. You have a single neutral.

My concern was your readings indicated you had an open neutral and may have grabbed one from a different circuit if the box you made the connection in has multiple circuits. If you have only one neutral coming into this box from the breaker box and the rest of the neutrals are going out to devices then you are OK.
 
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