Line fault at the outlet -- do I need an electrician?


Yesterday, I got a Panamax, Max 1500 surge protector and line conditioner. (I got a very good deal on it, and am just trying it out.)

I plugged it into an outlet I've been using for a while and one of the red lights on the front lit up saying "line fault." (I'm not sure how this is different from a "ground fault." Maybe it's the same.) The Panamax does not do this with other outlets in the room. They seem ok.

So, I know this means that the outlet is improperly wired. My question is, might this be a simple thing to check and/or fix? Any suggestions most appreciated. It's the only outlet I can use to have my audio set up where I usually have it. Now is not an optimal time to call an electrician. If this is a big problem, I'll try out my gear somewhere else in the room, but if I can fix this without too much expertise, that would be ideal.
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"I remeasured the outlet. Here are the readings that I got:
Ground to neutral slot equals 121.6ground to hot slot equals 3.6
neutral to hot equals 124.6Hot to neutral equals 124.6"
- Hot to Neutral 124.6   (let's call Hot - Line .. more typical term)
- Ground to Neutral Slot 121.6- Ground to Line Slot 3.6
I assume this measurement was made with almost everything turned off?
Hot-Neutral is 124.6 ... or about the same as Ground-Neutral + Ground-Line.  With a noise-free reading, (G/N) + (G/L) should approximately equal the source voltage at your electrical panel AND and should be higher than what you measure L-N at the outlet.


(G/N) + (G/L) = 125.2 - Or perhaps the voltage at the panel(L-N) = 124.6 - Or the voltage after all the drop(G/N) + (G/L) - (L-N) = 0.6


However, as stated G-N should be close to 0, but often is not due to drops in the wires (and noisy measurements). Given you have 3.6 with what appears a very small drop on L-N, that suggests either a noisy measurement (possible), OR, it could be a faulty ground connection on that line. Given the wiring issue already noted (and DIY nature), I would be investigating the ground integrity. Fortunately, you can do this yourself.

1) Turn the breaker off!!2) Wait 30 seconds (any leakage from capacitors in power supplies)3) Ensure the L-N, G-L and G-N voltage is 0.  I am expecting G-N is 0, but if it is not really close with power disconnected, that is an interesting result. If it is no 0 or really close, DO NOT CONTINUE!
4) Repeat step 3! ... you really need to be sure.5) Put your multi-meter on the ohms setting.6) Measure the resistance between the Ground and the Neutral (the ones that was measuring 3.6 volts). It should be <1 ohm with a good contact between the probes and the socket.
Thanks for that process. It sounds like this test does not require me taking the outlet out --just testing the ohms with the multimeter. That doesn't seem very unsafe, but I'll follow instructions carefully if I do it.
OP:

Your circuit is fed from a sub panel, correct?  Is the circuit fed from an independent breaker, or is it a duplex?

Also, have you seen any boxes in  between the sub panel and the outlet?

Best,

E
Lastly, does the 4V on the neutral go away when the breaker is off?
@erik_squires 
  • Yes, 4v went away with breaker in off position.
  • Circuit is fed from subpanel, yes.
  • It is an independent 15A breaker switch.
  • I have not seen any boxes. The subpanel sends out a thick orange wire affixed to the ceiling (exposed beams) and then that line disappears up into the ceiling. I believe it's run along the length of the top of the house to feed the first outlets and then that is run down to the basement, where the other outlets and my audio gear is. All outlets show reverse polarity.