2 problems.......related ?

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  #1  
Old 01-26-07, 10:07 PM
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2 problems.......related ?

My neighbor called me over today and asked if i could help him with an electrical problem he wasn't able to figure out. The only tools we had was a cheap 2 prong tester (two wire leads with an indicator light) and one of those 3 prong plug tools used to check the wiring of wall outlets.

Problem 1: There's a 3 gang box inside the entry of the house with 3 switches. Switch 1 controls a porch light. Switch 2 controls a foyer light. Switch 3 controls a stair light (2 way switch) None are working. There's also a hall light switch thats not working (it's on the same circuit). I went over there thinking an open circuit. 1st thing i checked was the electrical panel. Used the two wire tester and checked each breaker with the ground bar. All breakers were on and the tester indicated voltage at each wire. Ok, 2nd thing i did was remove the 3 gang switch plate and loosened all the switches to let them hang out of the box. I was looking for any pigtails inside the box (I had a similar problem a few years ago and it turned out to be a faulty pigtail causing the open circuit). Everything checked good. Put the tester on one of the black wires on the switch and the other lead to ground. Tester indicated voltage present. Now i'm thinking "faulty neutral"? Put all the switches back in and removed the single hall switch (single pole switch) and same thing. Voltage present but....this is the part that confuses me. I had voltage at both black wires regardless of switch position. In a single pole switch application, isn't voltage supposed to be at both wires with the switch in the "ON" position and voltage at one wire with the switch in the "OFF" position?

I never checked the 3 gang box switches as thorough as i did the single pole hall switch. BTW, all switches involved are traditional type illuminated ones. I guess they have an LED in the toggle switch so you can see them in the dark.

Problem 2: Have no idea if this is related and have no idea why i even checked it in the 1st place. There's a wall outlet about 2 feet away from the 3 gang box by the front door. This outlet is hot at all times. I plugged the 3 prong tester in it and it indicated (hot/ground reverse) So, i remove the wall outlet and it's wired correctly. I went as far as removing the outlet completely and checked the source wire vs the load wire. When i used the cheap 2 wire tester on the source black wire, then to the source white wire, the indicator light barely lit. When i checked the black source wire vs the ground wire or the load white wire, the indicator light lit very bright. I went to the service panel and checked the hot wire for that wall outlet at the breaker vs the neutral wire for the same circuit at the grounding bus. Tester indicated voltage.

If my neighbor was confused before i went over, he's perplexed even more now just as i am.

Note: I don't know if that wall outlet is on the same circuit as all the light switches.


Any ideas what may be happening and what we should check next?
 
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  #2  
Old 01-27-07, 04:38 AM
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Your assumption of a loose neutral would explain all the symptoms that you posted. It does appear as though that wall outlet is on the same circuit.

The voltage you are getting on the load side of the switch that is off is from the blead through for the pilot light.

You will need to find out where the neutral is open between the panel and the part of the circuit that is failed.

Good luck
 
  #3  
Old 01-27-07, 06:00 AM
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Part of using diagnostic tools is understanding what the results mean. It does little good to use the tools if you do not understand how to use them or what the results mean. Unfortunately too many people never bother to read the directions that come with tools or the directions are inadequate.

jwhite has pushed you in the proper direction. An open neutral is to blame and has caused the hot/ground reverse indication. Finding power at both sides of a switch is easily explained because of light bulbs (or other loads) being present and reading voltage through those loads.

Check each and every receptacle, switch and light on the circuit. As you are checking move any back stabbed connections to screw terminals and redo any wire nutted connections. You must check every location on the circuit, working or not. Somewhere on the circuit, possibly even at the main panel (although usually not there) there is an open circuit. Ultimately it will be at the last working junction box or at the first non-working one, but those two locations are not always easy to determine.
 
  #4  
Old 01-27-07, 10:53 AM
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Thanks guys, i'll try what you suggested today and post back any findings.
 
  #5  
Old 01-27-07, 08:32 PM
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Found the problem (bad pigtail) inside the hall light ceiling box. Figured i'd start there since it was the furthest point, then i would work my way back to the service panel. I got lucky starting there.

Thanks for all the help fellas.
 
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