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-   -   Open circuit has power, close the circuit no power??? (http://www.diychatroom.com/f18/open-circuit-has-power-close-circuit-no-power-48384/)

BeginnerHomeDIY 07-08-2009 11:12 AM

Open circuit has power, close the circuit no power???
 
A little background: a couple days ago I had a window air conditioner and a treadmill running on 2 different outlets in the same circuit. After a 10 minutes or so, they both went off for a couple seconds then both came back on but something started to smell so I turned both off. Several hours later I tried turning the air conditioner back on and it worked for several seconds before turning off. Then I tested the rest of the circuit and found that none of the outlets were working but the circuit breaker was still on for the circuit. We thought maybe the outlets had been broken/short-circuited somehow so we replaced them and in the process figured out that the outlet would have power as long as the wires going away from them weren't connected to anything.

So right now I have a first outlet that connects to a 2nd outlet that connects to a ceiling fan and the 2nd outlet also goes onto a 3rd outlet that also has a switch that goes to a ceiling light. Right now the wires from the switch go to the ceiling light area but are not connected to anything and the other wires from the 2nd outlet go to the ceiling fan area but are not connected to the fan. With the circuit on like this, the 3 outlets work and the loose wires at the ceiling light area (with switch on) and at the ceiling fan area say they have power using a light-up circuit tester. But when we connect the ceiling fan to the wires then the ceiling fan doesn't work and nothing else in the circuit works. What's wrong?

InPhase277 07-08-2009 11:28 AM

You really need more than a light up tester, but it sounds like the neutral (white) is open somewhere. Start at the panel, and identify the circuit and corresponding white wire on the neutral bar. Make sure it is connected good there.

joed 07-08-2009 11:59 AM

When you say they "worked" did you have a lamp or something plugged or only using your tester? I suspect you have an open connection on the cirucit somewhere still. It could be in the panel.

BeginnerHomeDIY 07-08-2009 12:02 PM

I've only used the light-up circuit tester to test the outlets and the loose wires. Could it light up but if I tested a lamp in the outlet then it wouldn't work?

joed 07-08-2009 12:28 PM

Quote:

Originally Posted by BeginnerHomeDIY (Post 299005)
I've only used the light-up circuit tester to test the outlets and the loose wires. Could it light up but if I tested a lamp in the outlet then it wouldn't work?


That is exactly what I suspect is happening. You have a high resistance connection and as soon as you put any load on it, it measures open. Those light up tester do not draw any current and can easily get fooled.
The ceiling light is applying a load. I suspect if you apply the load to another part of the circuit you will have the same results. This is a very common problem if your receptacles use the pushin back stab connections. The wire connection should be on the screws.

BeginnerHomeDIY 07-08-2009 12:37 PM

So how do I tell where the loose/bad connection is? If the circuit is on but a lamp doesn't work in the first outlet then does that mean the bad connection is for sure between the main circuit board and the first outlet in the circuit?

Yoyizit 07-08-2009 01:00 PM

Quote:

Originally Posted by BeginnerHomeDIY (Post 299019)
If the circuit is on but a lamp doesn't work in the first outlet then does that mean the bad connection is for sure between the main circuit board and the first outlet in the circuit?

Yes.
The real test of a good connection is to see less than a 3v drop at the outlet when you plug in a hair dryer.

joed 07-08-2009 03:40 PM

The loose connection is in the first not work or the last working device on the circuit. It could even be in the main panel.


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