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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Showing 30 responses by hilde45

Thanks, Jim. Later today, I will probably try this. Or tomorrow.

Before I proceed -- I want to be clear that so far I have tested multiple outlets on this daisy chain -- they all read as reversed.

I do not yet know how far back they go. 

QUESTION: Are you suggesting that I try to *just* deal with the outlet nearest my gear? Or are you saying that I should deal with something at a prior step in the chain (nearer) to the breaker box?
Thanks for the safety suggestions, all. I aim to have a dedicated line but that has to wait on some home renovations. At the moment, I just want to locate my gear where the shelves, etc. are -- but that's where the weird outlets are. I'll be careful.
Thanks, Erik, almarg, jim — thanks.

So, our house is a mixture of old/DIY and new (renovation); the problem is with the old part of the house.
Almarg — I have not tried measuring with everything on the chain unplugged. I'll do that when possible.
As far as finding the outlet closest to the panel is a bit tricky, as the wire which feeds things disappears into the ceiling and I'm not sure where it goes first. I'm sure where the 3rd, 4th outlets are, but not the 1st, 2nd ones. If the problem was at the panel, that's at least clear. If it's not at the panel, then I suppose I can just *try* what might be outlet #1, first, and see what I find.

I'd love to avoid opening the panel, but from what I gather, this is not so hazardous if I'm only looking.
Thanks, all.
I ran out of time today, but I'm going to
(a) unplug all things on that chain
(b) measure again to see if the 4v are still there
(c) turn off the breaker and measure everything before (and more) again to see if there's leakage
(d) perhaps take off the breaker cover and see how that breaker is wired — WITHOUT touching anything.

I'll try to report back in case you all are still interested in interpreting.
This is really helpful.
OP again:
I'm pretty sure I unplugged everything on the chain of outlets.
I have not thrown the breaker yet.
All outlets on chain read as reversed:
*  the negative plug input reads as 120v, more or less
* the positive plug input reads as 3.4v, more or less
* Unplugging all things in the outlets made no difference to the 3.4v reading.
* On other chains in the house, things are not reversed. They read zero from the negative input plug.

Jim: "Is the wiring in the old part of the house original wiring? Any idea what year that part of the house was built?"
Not likely. House built in 1910.
I don't know what else is on the circuit. I need to test.
Other questions will require inquiry, and I'm a novice, so may be inconclusive.

Cissado -- I will avoid opening the panel. I like your idea of trying to fix it with a receptacle.
I will watch for switches, and try the disconnect method.

Bottom line is that I'm curious up to a point. I am suspicious of the overall electrical job done in the older part of the house (DIY from previous owner). So, it won't take much to push this off onto a fully qualified electrician who will be working on other jobs (and perhaps installing a dedicated line).

The reason I'm curious now, as I think I mentioned, is that I'm trying out my audio gear and have been shoved to an inconvenient side of my room because of this polarity problem; so, a fix would be helpful in terms of audio set up.

I'll try to update soon. I have a stack of midterm exams to grade. (He says, posting on Audiogon anyway. ;-)

Thanks, Jim. And I'm not doing anything without rereading these posts and triple checking things are dead. And if I'm even 10% uncertain, I'll just skip it!

But I'm learning a lot and so there's already been a payoff.
"Does it read higher voltage in the other outlets?"
Yes. I'll compare different outlets and stop using the bad one.
Thanks, Mesch. I'll test.
No, it's not GFCI, just an outlet run down from another one in the room.

I could get a tester if that could tell me that what is wrong is something I could fix myself (assume I have no knowledge, except to turn off the breakers). The Panamax is already showing that it's reading below 115 v and has a fault of some kind.
Thanks, Bryhifi. I think I could at least take a look. It's two different outlets that have the fault -- one feeds the next one. I wonder if correcting the root might also correct the branch.
That's fantastic -- thank you so much. It's a snowy day in Denver today and I am shut inside. I'm printing this out for reference. 
@bryhifi I have a digital multimeter. I use it to test car batteries. I suppose I might use that, too, no? In any case, I can get the three prong outlet if necessary. Thanks for the picture you sent -- I've saved that.

@cissado @heaudio thank you for your advice, too. 
Ok, here are some results.

TESTS for two connected outlets:
Ground contact of wall outlet TO Hot contact slot = 4 volt reading
Ground contact of wall outlet TO Neutral contact slot = 120 volt reading

TEST for another outlet on a different circuit in same basement:

Ground contact of wall outlet TO Hot contact slot = 124 volt reading
Ground contact of wall outlet TO Neutral contact slot = 0 volt reading

I suppose this means I have reversed polarity on those problematic outlets?
I don't know why I got a 4 volt reading in from those outlets.

@cissado -- I would need to reverse the initial one, no? Or perhaps it's messed up all the way back at the box? I am shying away...
OP here. Sorry, had some family stuff to take care of.
Multimeter is an all sun EM830 multimeter.
I don't know if it has an autoscale.

I'm about re-test all outlets with the meter, after unplugging everything on that line (I hope. I need family to all wake up so I can see if the outlets in their rooms are part of the branch. This could be a little while.)

An image of the multimeter is here:

www dot jbryant dot eu/pages/DMM dot htm

I used the scale in the upper right that says V~ and has the numbers 600 and 200.
I set it on the 200 scale.
I re-tested and got a 3.7 reading.

I still need to unplug everything and get back to you.
Gotcha. Time to throw the switch.
Thanks Al. Your use of all caps is exactly what they were meant for.

I won't open an outlet until I'm 110% sure it's off. After all, I've pledged my life to the COVID virus; I can't cheat it by electrocuting myself. (Please pardon the gallows humor. It's all I've got left, except for an obsession with audio.)
Some answers to questions posed earlier:

I threw the breaker.

This circuit runs back to the main panel on a 15 amp breaker.
This circuit runs:
outlets downstairs
outlets upstairs
ceiling lights

I turned breaker back on.

Some data:

The multimeter says 3.4. I see nothing that would indicate it is mV. When I test the hot plug it says 117.4 (etc.), so these all seem like volts.

Yes, there are some ceiling lights fed by the circuit.

Strange finding within the same circuit:
I tested a ceiling light can. I touched the red probe to the center and the black probe to the sides of the can and got 117 volts. That seems like the polarity is correct.

However, in the outlets in this same room and elsewhere on this circuit (as reported), the polarity is reversed.

I have not yet examined a receptacle with the power completely off and dead.
I will go measure the light can again but I need to figure out where to touch the probes.

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
Got it. All those are good questions, but I think the ultimate solution is to delegate this whole thing. But now I know what to ask the professionals. This amateur is sticking with writing and teaching. Thanks again.
Jim, all,

Thanks SO much for sticking it out on this detective inquiry!

The 4v issue is weird, because the multimeter does not read 4v on a properly wired outlet on a different circuit.

I'm glad the Panamax revealed the issue, though, especially if there's a safety issue.

Thanks for the options. (1) & (4) are the most attractive and would tie in with an electrician, but won't happen for a while.

(2) Reversing seems possible. QUESTION: Is it safe to have one reversed outlet? I guess I don't see why not, but I just want to make sure I am understanding.

Thanks for the hint about changing the light bulb. In sum: either (a) unplug the lamp or (b) make sure it's off before changing the bulb.


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.
@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.
Maybe the terminology is messing me up.

I have one panel in the house.

At the top, is the master on/off. Below are the breakers. I thought that's what you meant by subpanel. It is not a separate panel, in the sense that it is not another separate metal rectangle. There is one metal rectangle.

The subpanel contains, maybe, 30 breakers.
I followed a bunch of wires out of the box (9, 10?) and the orange one split off to the side of the house where I presume it is feeding the circuits/branch I mentioned.


Yes, I definitely do not have a subpanel.
Appreciate all the comments.
For me, this is adding up to waiting.
If I change my mind, I'll update.

You're a generous group of people.

I wish you health and as much happiness as possible.
UPDATE: Trying to restart this thread with a more general but related question about powering my equipment. Please do not suggest getting a dedicated line. I agree that is the best thing to do and I will do it eventually. This is about solving a problem in the meantime.

Some quick facts:

POWER (receptacles/outlets and equipment):
1 *nearby* properly grounded/polarized receptacle w/ 2 outlets
1 *12 feet away* similarly proper receptacle
1 Panamax line conditioner with 10 plugs in the back

COMPONENTS TO BE POWERED (7):
2 monoblock amps.
1 preamp
1 powered subwoofer
2 sources (Streamer, CD transport)
1 DAC

QUESTION: I’ve heard that one should plug amps directly in the wall. If I do that, I use up both receptacles. I also forego a surge suppressor.

What is the best way to provide power to everything I have?

Options I’ve thought of:

(a) Put a multi outlet cover over the receptacle and provide 6 outlets from one receptacle. I have one from Monoprice I can use. I would plug in both amps (and perhaps the sub) directly and then the Panamax for the rest.
(b) Plug the amps directly into the wall and then run a thick extension cord from the receptacle #2 down to my Panamax conditioner for the Preamp and source components
(c) Plug in the Panamax into one outlet and just plug everything into that.

Other options? Cautions? Any advice? Thank you!