outlet only dead when something is plugged in... ?????

17 years ago

Any suggestions to the following, it has me baffled.

Background - A 120v outlet on our back porch went dead. I tested the outlet and it showed no power, the lines were live though.

First puzzle - there are two electrical lines in the box, each with a positive and negative. I checked them all ; testing (+ & -) from the same line shows them dead. Crossing over and testing a + from one lead and a - from the other lead shows power. It doesn't matter which set, only that it is crossed.

First solution - Okay, I got power, even if it is strange. I replace the outlet, hook everything up and nothing. Recheck the leads and there is power...

Second Solution - I remove one lead from each line and test the outlet - it shows power. I put everything back, plug something in and nothing.... I check the outlet with something plugged in and it shows nothing. I unplug the outlet, test and it shows power. I plug something into the other side of the outlet (the exact one I just tested) - Nothing again.

Second puzzle - I plug anything into the line other than the tester and it goes dead but the tester shows power. (It's just one of those twin leads with a light in the middle). Could there just be a small trickle of power that lights up the tester but not 120V? Yet there is no resister anywhere along the line, how would it drop from 120V?

Before I plug myself into a working outlet, give me some thoughts.

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Comments (5)

bigbird_1
17 years ago
There are no + and - wires in 120V AC, only hot, neutral, and ground. How did you test the outlet with something plugged in and it shows no voltage? Did you touch the probes to the brass and silver screws of the receptacle? If so, it doesn't matter if something is plugged in or not. If the cc't is hot, it'll show 120V AC regardless of whthere a device is plugged in or not. Get a voltmeter for proper diagnosis.This outlet is in all likelihood GFCI protected. Check for a tripped GFCI somewhere upstream.
ombligo
Original Author
17 years ago
No GFCI, already considered that. Plus other outlets on the circuit are fine.

I was using + and - just to simplify.

I've tested by inserting the probes into the outlet when nothing is plugged in (shows hot) then while something is plugged in (shows no current) and then unplugged it and tested again (shows current).

I only lose current when something is plugged in.. tried both top and bottom outlet - no difference.
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joefixit2
17 years ago
The problem is upstream. Check the other receps on the circuit for a bad connection. Plug a table lamp that you have turned on into the non working recep. Then, while someone watches the lamp, go around an plug something into each upstream recep and wiggle it around. When the table lamp flickers, you have found your bad connection. It will most likely be the neutral(white).

Another possibility is a GFCI that you think is reset but it is not. The ones with the black and red buttons do not always reset easily, sometimes not at all. Since this is an outdoor recep, depending on when your house was built, it should be on a gfci, maybe the one in the bathroom?

And a third possibility, are you sure the recep is not switched?

Your test results indicate an open neutral, could be caused by any of the above (including a switched neutral).
dozer
17 years ago
you don;t say what you are using to test with. If it is a neon tester or a digital multimeter, you could simply be getting a false reading where there is no actual voltage but are picking up ghost voltages or local emf.
DavidR
17 years ago
Sounds like a bad connection as Joe suggests. A neon tester or high impedance DMM will often show voltage present if there is a high-resistance bad connection in the circuit. As soon as you connect a substantial load, the measured voltage falls to zero.