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

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.

Assuming that the "can" you refer to is the socket into which a light bulb is inserted you were measuring between hot and neutral, rather than between safety ground and each of the other two wires (hot and neutral) as you were doing on the outlets. And if so, the measurement says nothing about polarity. Since this is AC you would have obtained the same reading if you reversed the connections of the red and black probes.

I’m surprised, though, that the reading was only 117 volts, and I'm not sure what to make of that. At the miswired outlets you variously measured 3.4 to 4 volts between ground and the miswired neutral, and 120 volts between ground and the miswired hot. And you measured 124 volts between ground and hot on other outlets in the same basement that are properly wired. As Jim pointed out earlier 120 + 4 = 124 volts, which seems unlikely to be a coincidence.

On the miswired outlets what do you measure between hot and neutral? As far as I can recall that has not yet been measured.

Best,
-- Al

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

@ hilde45 OP

Yeah, you got a lot going on there. And all that on #14awg wire to boot. It’s been like that, I imagine, for many years and you didn’t know it. That is, unless the 15 amp breaker was tripping occasionally from being overloaded.

You didn’t know the AC polarity was reversed at the wall outlets either, until several days ago. (Not mentioned in this thread, reversed AC polarity can have an affect on the sound of an audio system. But that’s for another thread.)

As for the 4 volts you measure from the neutral to the equipment ground that really doesn’t matter. The 4 volts may not even really exist. It could just be phantom voltage created by the multimeter. Even if the 4 volts is real it’s to low to be an electrical safety/shock hazard.

This all started because you bought a ’ Panamax, Max 1500 surge protector and line conditioner’. Then when you plugged it in it said you had an AC mains line fault. If you hadn’t bought the darn thing you wouldn’t have been going in circles the last several days trying to figure out what the problem is.

Options, the way I see it.

1) There is way to much going on with the branch circuit wiring for you to repair. Not to mention your qualifications.... You maybe a great teacher, but a lousy electrician... An electrician could spend a couple days, maybe more, straitening out the mess. It all comes comes down to time and money. You have the money, he/she has the time.

2) Reverse the Hot and neutral wires at the duplex receptacle outlet the power conditioner will be fed from. I assume the duplex outlet is used to feed all of your audio equipment.

3) If all of your audio equipment will be plugged into the power conditioner you could reverse the Hot and neutral wires on the power cord plug of the cord used to feed the power conditioner.

4) Hire an electrician to install a new 20 amp dedicated branch circuit for your audio equipment.



Note:
There are instances where reversed AC mains polarity can be an electrical shock hazard. In the case of screw in light sockets. If the mains polarity is reversed and the circuit is hot, on, feeding the light socket the outer screw shell of the socket will be Hot with respect to ground. To lesson the likely hood of receiving an electrical shock in the event one hand is in contact with the outer shell of the light bulb, while it is in contact with the shell of the light socket, and the other your other hand is touching a grounded object MAKE SURE the switch is in the off position. If the light has a cord and plug you can always just unplug it from the wall when replacing a burned out light bulb with a new one one.



Jim

.

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.

hilde45 OP303 posts

03-26-2020
11:12am

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

Apple to oranges, imo.
What is the wire gauge size of the other branch circuit? What is the total length of the branch circuit? What is the total connected load on the circuit? What is the type of devices that are connected to the circuit? How many CFL and or LED lights are connected to the branch circuit? What is the voltage drop on the circuit that you didn’t measured the 4V neutral to ground voltage?


You have all kinds of things going on with the branch circuit where the wall outlets have reversed polarity issues. You now know the branch circuit feeds outlets on the first floor and the basement. You now know it feeds ceiling lighting. How many CFL and or LED lights? They spew all kinds of harmonic noise back on the AC mains. Who knows what that does to your cheap multimeter.

There is still a very good chance the 4V is caused by voltage drop. Now that you know the branch circuit feeds outlets and ceiling lighting on the first floor, not just the basement, turn off all the connected loads that are connected to the branch circuit. Check for the neutral to ground voltage again. No load, no voltage drop.

As for the power conditioner showing an AC mains ’Line Fault’ condition. Correcting the AC polarity reversal problem, will solve the power conditioner 'Line Fault' problem.


Jim.