Locating Loose Neutrals

Thread Starter

illusha

Joined Mar 11, 2019
17
Working on my own 2-story house built in 1947 that has been, umm, "remodeled" by a house flipper right before I got it. There is a new 200A main panel, but the way it's wired, well, let's say, is still old school. There is just one breaker, 15A AFCI, that controls both upstairs bedrooms, upstairs bathroom with GFI, part of living room, and some other random parts of different rooms wired to it. I'm assuming it's likely how it was wired back in 1947 because other "extras" that have been added over the years are now on separate breakers.

Problem - one outlet has not been working ever since I got it 2 years ago - just now starting to troubleshoot it because it never gets used. Nothing works when plugged into that outlet. I actually measured the voltage on it and got 27v out of it. Did some googling and found out that it's likely to be a lose neutral "somewhere" or a bad backstabbed connection.

Started by poking around various devices on that breaker with a non-contact current tester and a multimeter. All devices actually work besides this 1 outlet. Some devices read 110v as they are supposed to. Some switches read 27v when measured with a multimeter, but the lights connected to them still work fine, most lights are LED. Still strange.

I found several switches that have been "backstabbed" instead of using side screws and thought I got it. I replaced those switches with brand new ones, since they were old anyway, but nothing changed. So the problem is somewhere I haven't checked yet. There are around 40 different devices on that circuit.

Question - what is the best way to locate the loose neutral? I can pull apart (and replace) all switches and outlets to make sure there are no wires that are physically lose (or have been backstabbed by the house flipper). I suppose I can pull all light fixtures and check those too. Doubt that the lose wire is inside the panel, possible, but doubt it because of 110v on *some* devices.

All boxes that contain devices have no wire nuts - they are done the old school way - soldered together and wrapped with tape. Am I supposed to take each of those bundles apart and redo them? I'm afraid of running out of wire length and having to run new wire. It's a 2-story house and running new wiring would not be a fun task. I just did a full rewire job on my other 1-story house of same vintage next door and I'm not looking forward to such a task in a 2-story building.

Thoughts on where to start? Ideas on why some devices are 110v and some are 27v if they are on the same breaker (and probably should be sharing the same neutral)? Any other words of wisdom? I've called a good electrician that I've worked with before and he said that he would do the same - check all devices one by one - which can cost quite a bit (depending on how lucky they get in locating the source of the problem). What's the most time-effective way to approach this task? P.S. Sorry for the long write up. Never been a man of few words.
 

crutschow

Joined Mar 14, 2008
26,361
I assume those sockets do not have a three-wire safety ground connection.
If not, then run a small test wire from an earth ground (perhaps a faucet pipe) to the sockets you want to measure.
Measure from the hot lead to that ground lead
If you get full voltage, then it's a neutral failure.
If you don't, then there's a break in the hot lead to that point.

Of course there's still the problem of determining where the break is located.
There are devices that are designed to detect a wire in the wall (I have one), that may help you with determining how the outlets are daisy-changed, and thus the break location.

The 27V is likely just capacitive pickup from an open wire.
 

Thread Starter

illusha

Joined Mar 11, 2019
17
Does anyone think that the soldered joints might be a problem? I am getting mixed answers from different sources. To me, it seems highly unlikely that soldered joints that have been fine since the 40s would lose connection, but I know in automotive applications solder sometimes corrodes and causes issues. What about in the house?

I can pull every switch and outlet to examine (and might as well replace them) and check all light fixtures for a loose neutral.

But what about them soldered joints???
 

MrChips

Joined Oct 2, 2009
22,879
I would check all devices, one at time.
If you have one flaky connection you run the risk of starting a house fire and burning down your house.
 

Thread Starter

illusha

Joined Mar 11, 2019
17
Copy that. It's been fine for 2 years with that one outlet not working, but I understand, it's just a matter of time till a bad connection heats up enough. I will also check the panel to make sure all wires are tight. And I was told that light fixtures in older houses might also be a cause because they used to take power from them. Not looking forward to this job, but needs to be done, please chime in if anyone thinks of anything else for me to examine.
 

BR-549

Joined Sep 22, 2013
4,938
I would suggest making friends with an electrician and start re-wiring that house. Do one or two rooms a month. It does not cost a fortune. If you are allowed, where you live. You already have panel in. No more inspection should be required. Sounds like you have room for the proper circuits to be wired in.
 

sghioto

Joined Dec 31, 2017
2,068
please chime in if anyone thinks of anything else for me to examine
Have you tried just checking the outlet that is not working before you start tearing the whole house apart? By checking I mean removing the outlet for examination.
Another though, is it possible that outlet is controlled by a wall switch?
SG
 
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Thread Starter

illusha

Joined Mar 11, 2019
17
Yes. I started at that one outlet. And, yes, it is controlled by a switch. The switch interrupts hot. Neutral wire is not even cut at the switch (only hot is) and neutral wire just goes right through to the outlet. Both switch and outlet visibly seem fine and use screws (not push in). Outlet gets no power when switch is off. It gets 27v when switch is on. But several other switches and outlets in other rooms (on the same circuit) also get 27v. My research tells me theres a loose neutral *somewhere* on the circuit. Everything is old, but a few devices have been "upgraded" by the house flipper, some of those were backstabbed to daisychain within the box. The ones I replaced so far made no difference.
 

Thread Starter

illusha

Joined Mar 11, 2019
17
I also just examined the panel and 75% of neutrals inside the panel have various wire nuts or crimp connectors. I'm assuming that when the house flipper had a new panel installed, they cut existing wires coming out of the wall and used these extensions to the neutral bus. I'm going to have a trusty electrician look at it on Friday. But he looked at the photos of the panel I sent him tonight and he still thinks that it's more likely that one of the devices or lamps on the circuit has a loose neutral.
 

Thread Starter

illusha

Joined Mar 11, 2019
17
Same here. And I also dont understand how some switches are measuring 27v and yet the lights they power still work. They might be LED, but it does not make any sense, thus this thread. I'm now reading other threads on this forum that discuss floating grounds in main panel and varying voltages smoking electronics. I was concerned before and this is not helping. I should have probably just left that non working outlet alone and kept living with no stress. But now pandora's box has been openned...
 
I have some ideas:

#1 you say 27 or 120. Turn off that breaker and now locate every outlet/light that is on that circuit.
#2 Attempt to "guess" the wiring path.
#3 See if you can find the "end outlet"
#4. Disconnect all devices. Hopefully none have 3 prongs. Maybe the 27 V will go away.
#5. both hot and neutral at the fuse box.
#6 make sure the 27 V goes away.
#7. if it doesn't disconnect other breakers. It may be capacititive pickup.
#8. get a LONG extension cord. Connect ground at the box. Connect the free neutral to the Neutral of the extension cord. Hot disconnected.
#9. Take a voltage first between N of that extension cord and then an ohm reading.

You really want to do the bisecting stuff, but you really need to know the path. So, do the middle and the end first. If you find something, bisect the route that doesn't work.

if you can bisect the system, you get to the problem quickly.

Suppose you had 18 things and you know the order. Powers of 2 are 2.4.8,16,32,64. It's easier to pick the 16 th to start.

So is it between 1 and 16? yes. Pick 8. Is it between 8 and 16? yes. is it between 8+4=12 and 16? yes. Is it between 14 and 16; Yes. So it's 15.

the method is quick.

Non-contact voltage detectors would work if the problem is with the hot to give you an idea where the wire is going.

The Ideal Suretrace is a device that will locate the path of a wire in a wall. Be careful, the model numbers are similar, but don't have the same functionality.
 

Thread Starter

illusha

Joined Mar 11, 2019
17
Ah. So *that* is what the electrician I know meant by saying they "start in the middle" when they look. Thanks! I'll give that a shot this weekend. Hopefully I will survive till then as is. And I will be looking to add a good tracer to my tools collection.
 
It's called binary searching. When searching for a signal, you at least verify it is present at the input and not the output.

In computing, you generally have a sorted list. Now what if you want to find someone in that list? You start in the middle and keep trying to find what part of the list they are in.

I don't like using the real middle. Using a power of 2 makes the algorithm easier.
e.g. 2,4,8,16,32,64,128,256,512.1024,2048.4096,8192,16384,65536 etc.
 

MrChips

Joined Oct 2, 2009
22,879
First appearance suggests that your non-working outlet has its NEUTRAL line disconnected.
That does not explain why you are showing 27V at working switches and outlets.

Let us not overlook the embarrassing and obvious mistakes. A lot of silly things occur over remote diagnostics here on AAC.

Are you sure you have your test meter set to the correct range?
Show us a photo of the test meter set to your measurement range.
 

Thread Starter

illusha

Joined Mar 11, 2019
17
Thanks for the additional ideas. The non working outlet has both hot and neutral connected. And I know how to use a multimeter. It's auto ranging, so the only thing to select is AC or DC, so I think I got at least that part. I wish it was that simple : )

Someone on another forum suggested that there might be some knob and tube wiring remaining in the wall. They used to switch neutral back in the day. A suggestion has been made that the house flipper spliced to make 2 neutrals going to an outlet. I will be checking for that also. Although I'm not sure how 2 neutrals would give 27v reading?

I'll need to wrap my mind around starting testing in the middle once I wake up some more. Only had a few hrs of sleep last night reading the forums. I'm on US Pacific time, if anyone was wondering, and the daylight savings kicking in last weekend is not helping.
 

billnow

Joined Aug 4, 2010
18
Try plugging in an incandescent lamp (or other resistive type load) into the outlet that reads 27 volts while measuring the voltage at that outlet. If the voltage goes down considerably then you're shown that there is a capacitive connection, and not a "real" connection. The bulb should not light fully if only 27 volts is available.
Secondly, another possibility is that you may have an outlet box that has been abandoned and covered up somewhere behind a wall.
 
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