Trying to resolve an Open Neutral issue

[Todd.Brock]

My house is 30 years old. I have a recepticle on the back of the house I was using today. It is protected by gfci. It's a 15 amp circuit. All gfci are on same circuit in the house. There is only one test reset button in garage. The outlet has currrent on both the hot and neutral side. I replaced the outlet, replaced the gfci , tested at the gfci to see if functioning , but can not figure out what's happened a DMM only shows 120v- i have started to test other outlets- but they seem like they are ok.


If I find a faulty outlet- is it possible that it is feeding the hot side as well as the neutral? My miter saw works fine on other outlets so it isn't smoked. I shut the breaker off for safety.

Any thoughts on where to start? I have tested outlets with a Klein proximity sensor that beeps when it senses electricity. Not getting anymore than 120v exactly but on both sides. I also found two other receptacles - presumably down stream that do not light up the circuit breaker finding tool. Help!

 

[ddawg16]

Re: Finding current on a neutral wire

"Outlet has cured"..........can you translate that?

 

[Zeke]

Re: Finding current on a neutral wire

"Outlet has cured"..........can you translate that?

current. You have to reach to the title to understand...

 

[LXCam]

Re: Finding current on a neutral wire

Current aside could you explain it differently. I'm really having a hard time with it. So i take it the gfi trips when you use your miter saw or all the time with nothing plugged in.

 

[Todd.Brock]

Re: Finding current on a neutral wire

Auto correct - thanks for the grammar correct. Any thoughts on how a neutral could be receiving current that is downstream of a gfci outlet?

 

[LXCam]

Re: Finding current on a neutral wire

Auto correct - thanks for the grammar correct. Any thoughts on how a neutral could be receiving current that is downstream of a gfci outlet?

Current and voltage are two different things. Current Is the amperage used by whatever you have plugged in.

Here's a simple test. With a meter, obviously not a non contact voltage stick. Measure from the hot to the neutral and hot to ground, they should be the same. If they are not within a volt or two then measure from the neutral to the ground. If there is more then a volt or two present you have a problem upstream from that point.

 

[Zeke]

Re: Finding current on a neutral wire

Using a DMM you may be seeing phantom voltage. There could also be some really mickey mouse wiring, but let's leave that for the moment until we find out more.

 

[Dyt]

Re: Finding current on a neutral wire

One GFCI as the lead receptacle on the circuit. It protects the remaining receptacles. You should not have more than one.

 

[wyliesdiesels]

Re: Finding current on a neutral wire

Boy I hope Im not the only one having a hard time understanding ehat the issue is. Thr OP said he gets 120v reading with a DMM.

OP what is the issue u are trying to fix?

 

[larry_g]

Re: Finding current on a neutral wire

First of all What is the problem that started this investigation?

Second, what test instrument are you using to measure with?

How much current are you measuring? This is in amps...

I suspect you are measuring voltage. Can you show us a picture of your testing setup?

lg
no neat sig line

 

[JimRB]

Re: Finding current on a neutral wire

So the DMM is reading 120V between the black leg and ground (expected), 120V between the black leg and the white leg (expected) and 120V between the white leg and ground (not expected)?

Does it do this when everything is unplugged from the circuit, i.e. when all downstream receptacles have everything disconnected?

 

[Zeke]

Re: Finding current on a neutral wire

Todd (OP), there is more we need to know. I'm not the 'expert' electrician around here but I think I can guide you to giving us the overall information needed to see what's going on.

First, are there any devices plugged in anywhere on this circuit? Maybe something like a timer or transformer. To troubleshoot and diagnose any electrical issues you have to strip things down to the basics. You may have an "open neutral" situation which should not be taken lightly.

I'm not sure if I or anyone else here can tell how this GFCI is wired.

But one thing to find out is how much current is present on this neutral and how you are measuring it. You may see a load on this neutral but the meter showing 120v is also millliamps.

(And Larry and Jim got that in before I could.)

 

[Todd.Brock]

Finding current on a neutral wire

Sorry - I will try again. I have a 15 amp circuit protected by a GFCI- at the beginning of circuit & the only GFCI -that serves the basement, bathrooms and outside recepticles. My miter saw stopped working this afternoon. I assumed the recepticle was bad as its 30 years old and it was cracked. While investigating I also found 2 more recepticles notnworking

The recepticles in the bathroom have wires coming in and and out of the boxes. The outside box only has one wire coming in. It would appear to be the end of the circuit.

I can't find any other outlets to test in the circuit, this outlet is in the basement and works fine.

The is the other outlet in the basement. That plug is for the fiber optic internet service.

Because I had the spares- I replaced the GFCI at the beginning of circuit and the 3 recepticles not functioning. I used an outlet tester which told me open neutral.

I have a non contact tester, circuit breaker locating tool, DMM and now a outlet tester to diagnose. This problem just started today. Never had an issue with anything prior today.

I would appreciate some advice on how to troubleshoot an open neutral.

Thank you

Testing equipment

New GFCI with outlet tester

15amp circuit

One of the Three "bad" outlets.


Original recepticle that quit working


A recepticle on a different circuit

 

[Zeke]

Re: Finding current on a neutral wire

Well, now you've gone and mentioned open neutral. You're doing what any of us would do — be safe — and take apart everything on that circuit until you find the problem. With 3 bad (broken?) receptacles on the first shot there's bound to be others. You will have to get a continuity tester or switch the power on and off as you go. Might help to put a temporary switch in a convenient location.

Just remember, there can be juice anywhere coming from anywhere including back feeds. So don't touch things as you go until you've scanned the box with the non contact tester and then with the voltage tester as you take things apart. Label wires as you go. You think you will remember when you go to make this all back up but you won't if there's anything more than a black, white and ground at any box. You can be confused with switch legs. We don't know if you have a light fixture on this circuit anywhere (a good source of back feed when someone gets confused).

BTW, you can build a continuity tester out of a 12v light bulb, socket, battery, single spade connectors (or clip-on cord plugs), alligator clips and have a low voltage tester to use on DEAD circuits with the use of a long extension cord to go across the room or across the hall to test wires.

You don't by chance have AL wiring? You shouldn't at a house 30 years old.

 

[BillK]

Todd,
Have you tried it with the internet service outlet removed ? It may have some circuitry inside that is allowing you to see voltage on the neutral. Is that a pilot light on the front of it ?? That will do it. Like others said earlier, you have to remove EVERYTHING from the circuit before testing.

 

[Zeke]

Taking this one step at a time, you were using the saw on the last outlet and it stopped working. I assume that means the outlet went dead and the saw stopped (the saw is fine). Many times a bigger and frequent current draw will create a problem on a device that was just getting by before. IOW, the saw heated up a loose neutral connection and it went open.

Now when this happens, and if there is a load on the circuit that lost continuity to the panel, you see the load current on the neutral looking for a way back to the source. Find the open as I suggested and you will have fixed the problem.

You say, "I can't find any other outlets to test in the circuit, this outlet is in the basement and works fine." That's a little ambiguous but I'm following the best I can.

The only way to test the continuity of any wire is to isolate it and run some kind of current in it even if Morse Code. If you can't pick up the signal at the other end, it's broken!

 

[Todd.Brock]

Thanks all for the help. I appreciate it. I found that the Internet equipment is on a different circuit in the basement.

Zeke- Thank you. The basement outlet comment just meant that was an additional outlet on the circuit and I was trying to locate others- which I did not find.

The three "bad" outlets may have been good, but I replaced the devices to eliminate the variable.

I understand what you are saying, that I need to go to the boxes and check neutral connections of the last good outlet
I will start in the kids bathroom that is closest to the problem outlets in master bath.

Two questions- I have a tone generator for coax- I assume I could use that ? Do I need the light bulb and battery with the low voltage tester?
Also I was curious as to why I would be seeing voltage with the non contact tester on the last recepticle that was powering the saw- Wouldn't that point to a different issue with the hot and neutral making contact?

 

[Cmreschke]

No it wouldnt. Check the gfi that you installed to insure that all neutrals are hooked up. You may have missed 1 or possibly it came loose. Make sure the load side wires are connected to the load side of the gfi.

 

[Todd.Brock]

The GFI is good. I checked it last night when I installed the replacement. I verified with the outlet tester. I am presuming there is a loose neutral feeding the remaining three outlets. I am trying to figure out the best way to check continuity on a wire that terminates outside , two stories below.

 

[Zeke]

Tone generators work, again on isolated DEAD wires.

 

[Milton Shaw]

You need to remove all outlets from the each box and check each outlet to make sure 1. that they are not backstabbed connected, 2. the tie between each silver covered screw is still in good shape. (they can be broken off to create outlets with separate feeds). 3. that the white wires are all connected to silver screws and black wires to brass colored screws. This should pinpoint the problem and lead you to where to repair it. If there are any wire nuts in any box check them by pulling on each wire to make sure they are all connected by the wire nut. (Sometimes you twist them and one wire is never caught by treads in wire nut). I also would suggest because of the problems you are talking about I would turn off not only the affected breaker but the main also as you may have some cross wiring of circuits in the house.

 

[justsam]

Your problem is somewhere ahead of the receptacle that was used for the miter saw.

How are the receptacles terminated? Is the romex, which I assume is 14 gauge, inserted in holes in the back of the receptacle or attached via screws on the side? Use the screw connections please!

Are devices working downstream of the GFCI, and have you reset the new GFCI? A gfci will trip if current is seen on the hot and not an equal current on the neutral.

Be leery of using a tone device to find this type of issue. There can be enough coupling to pass tone, but not enough to provide a 15 Amp connection.

All boxes, except the end of circuit will have at least two romex in them. Make sure connections in each are tight.

 

[Todd.Brock]

Thanks again for the replies. I am not the most skilled with a DMM and did not realize it may have a tone function for continuity. I am going to have to rig up an extension cord to test for continuity. I'm not sure what the maximum length of "test" leads can be for a DMM. This is so I can get from upstairs outlet to outside outlet.

 

[Zeke]

Thanks again for the replies. I am not the most skilled with a DMM and did not realize it may have a tone function for continuity. I am going to have to rig up an extension cord to test for continuity. I'm not sure what the maximum length of "test" leads can be for a DMM. This is so I can get from upstairs outlet to outside outlet.

Be leery of using a tone device to find this type of issue. There can be enough coupling to pass tone, but not enough to provide a 15 Amp connection.

This is why you use a stronger battery powered continuity tester using any length cord or wire you want. Not a bad idea to do the test as you descibe as you will either find the open between the 2 or you can rule out that entire section of the circuit.

However, it doesn't take that much time to remove each device and after 30 years you ought to be doing every one anyway. The load from the saw killed the circuit and what justsam says there is how.

 

[Todd.Brock]

As I mentioned to Zeke in a PM- I rigged a set of test leads with a 50 ft ext cord and the continuity tester /beep on the DMM. The signal will travel at least that far. I found that the last good outlet thad a neutral that was loose. It wasn't falling out, but def need tightened. It was a spec outlet that had backfire clamps that screw down. Not the spring loaded type. That fixed the issue.

Thanks all who helped with replies. I have never experienced an electrical issue like this before. I will def be ready to troubleshoot next time something happens.

Thanks again

 

[justsam]

Todd,
Thanks for the follow up and letting the community know the outcome and what it took to resolve it.

Many on here will not recommend using the receptacle as a junction point, but rather using wire nuts to connect all the incoming and outgoing wires, with a single lead set going to the receptacle. This way the receptacle is not a junction but the wire nut connection is. Also easier to change receptacles should that become necessary since it will have but one black, one white, and one ground on it. A receptacle failure does not impact down stream sockets.

 

[Mustang51js]

Check to make sure the line and load on gfi are correct, take wires off gfi and find the hot set,that goes to line. If you have 120 volts at gfi,then the issue is the wiring going out after that,if you have power at gfi correct.

 

[Zeke]

Check to make sure the line and load on gfi are correct, take wires off gfi and find the hot set,that goes to line. If you have 120 volts at gfi,then the issue is the wiring going out after that,if you have power at gfi correct.

He fixed it. justam, that is a good reminder even if he has newer receptacles with the clamp style lugs.