120V Between Black/ground Wire But ONLY 11-12V Between Black/white??? - Electrical - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 02-08-2009, 09:31 PM   #1
Newbie
 
Join Date: Feb 2009
Location: Indiana
Posts: 5
Rewards Points: 10
Default

120V between black/ground wire but ONLY 11-12V between black/white???


Greetings all!

I've searched for several hours on the net but no answer to this problem, so I figure to give this direct query a shot...

My wife and I have had this house for a little under a year - 9 years old when we got it - and we've already had our share of annoying problems, but this one is truly perplexing. I'm no electrician but have been comfortable and successful around electricity in the past.

This started earlier this afternoon when I was painting downstairs in the basement, continuing the room that has been without these electrical symptoms in the past week. After plugging in a 300 watt halogen, I plugged in a radio in another socket and the halogen went out... I pulled the radio plug out and the light turned back on... I pushed the radio plug back in, there was a small greenish-blue "spark/flash" from deep inside the plastic box (the cover plates are off), and the light went out again. I pull the radio plug out but this time the light does not turn on - I figure I fried the bulb.

I pull out the plug of the halogen, push the radio plug in but it doesn't work. Ok... I go to the breaker box and, though the switch has not moved from the ON position, I do a manual reset: OFF then ON. I go back to the room and plug in the radio: nothing... nothing from the lamp either. Moving them to plugs on another circuit show that they are working.

I check all 7 of these duplex outlets in the room for voltage and it shows that I'm only getting 11-12 Volts across the black/white wires.

Additionally, the overhead fluorescent doesn't work either - it's switch is on the same breaker for the room - the wires measure the same: I've got 120V from black to ground and that same lousy 11-12V from black to white.

So now I figure it must be the offending outlet that "sparked" that is causing the trouble; I don't have an extra outlet for replacement, but I want to test this theory so I remove it and use twist wire connectors and connect the black wires together and the white wires together. Same measurements!?!?!

I'm now at a real loss... could this be a bad breaker switch at the panel?

Any help will be most appreciated and a big thank you in advance!

Sincerely, dumbo

Advertisement


Last edited by dumbo; 02-09-2009 at 11:58 AM. Reason: More accurate title
dumbo is offline   Reply With Quote
Old 02-08-2009, 09:36 PM   #2
Member
 
joed's Avatar
 
Join Date: Mar 2005
Location: Welland, Ontario
Posts: 8,359
Rewards Points: 3,512
Blog Entries: 4
Default

120V between black/ground wire but ONLY 11-12V between black/white???


You have an open neutral(white wire). If the entire circuit is not working then the problem is likely the connection in the panel.

Advertisement

joed is online now   Reply With Quote
Old 02-08-2009, 09:38 PM   #3
Electrical Contractor
 
jbfan's Avatar
 
Join Date: Jun 2004
Location: Newnan GA
Posts: 5,960
Rewards Points: 2,316
Default

120V between black/ground wire but ONLY 11-12V between black/white???


Do the same thing at the other outlet and retest. You have a loose or missing neutral.
__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"
jbfan is online now   Reply With Quote
Old 02-08-2009, 09:41 PM   #4
Member
 
Join Date: Jul 2008
Location: Iowa
Posts: 1,543
Rewards Points: 1,000
Default

120V between black/ground wire but ONLY 11-12V between black/white???


Kind of odd for a not so big load to do this, but I think loose connections did this. Turn the power off, and use the "ohm" setting (Ω) on your multimeter (picture of it below). Test between neutral and ground. Post results.

Test each junction (outlet, switch box, etc.) If you can't find it, shut your main breaker off (keep a flashlight on hand) and check the neutral for your circuit there.
Attached Thumbnails
120V between black/ground wire but ONLY 11-12V between  black/white???-multimeter.jpg  

Last edited by rgsgww; 02-08-2009 at 09:44 PM.
rgsgww is offline   Reply With Quote
Old 02-08-2009, 10:01 PM   #5
Member
 
Join Date: Oct 2007
Posts: 2,294
Rewards Points: 1,000
Default

120V between black/ground wire but ONLY 11-12V between black/white???


Residential troubleshooting 101.

As the others have stated, you have a very common open orbroken neutral.

Power comes to the recep on the black and goes back on the white. If the white wire connection is broken somewhere on the way back, the circuit is not complete.

You are reading voltage to ground because the ground wire is not open. It is still connected all the way back to the panel where it lands on the same bus as the neutral.

Bt far, the most common cause is a bad connection in a receptical.

The circuit goes from recep to recep to switch to recep etc.

Remove the first non working recep or the last working one on that circuit. The circuit relies on a connesction built into the receps and they have a tendency to fail when they are connected via the backstab rather than the side screw terminals. The bad connection could be anywhere between the recep and the panel but generally the culprit is in a recep.

Last edited by 220/221; 02-08-2009 at 10:04 PM.
220/221 is offline   Reply With Quote
Old 02-09-2009, 11:39 AM   #6
Newbie
 
Join Date: Feb 2009
Location: Indiana
Posts: 5
Rewards Points: 10
Default

120V between black/ground wire but ONLY 11-12V between black/white???


Quote:
Originally Posted by joed View Post
You have an open neutral(white wire). If the entire circuit is not working then the problem is likely the connection in the panel.
Yeah, this is what I am thinking, but I just don't understand what could be going on there: corrosion, loose connection? And how could that be related to plugging a radio into an outlet, and that little spark/flash I saw? Since that point the whole circuit is indicating this open neutral...

Quote:
Originally Posted by jbfan View Post
Do the same thing at the other outlet and retest. You have a loose or missing neutral.
All the outlets are testing this "low voltage" (now 10-11V) hot-neutral load (in fact, found two more on the same breaker, just outside of the room). The outlet the halogen was plugged into has only one each of the hot and neutral wires, so there's no way for me to isolate it like the other one by removing and wire nutting.

Quote:
Originally Posted by rgsgww View Post
Kind of odd for a not so big load to do this, but I think loose connections did this. Turn the power off, and use the "ohm" setting (Ω) on your multimeter (picture of it below). Test between neutral and ground. Post results.

Test each junction (outlet, switch box, etc.) If you can't find it, shut your main breaker off (keep a flashlight on hand) and check the neutral for your circuit there.
Testing between neutral and ground on each of the outlets with power off unfortunately showed no measurement... touching the probes together registers "0", but touching neutral and ground got no movement away from "1" regardless of Ω setting... I'll have to wait to get back from work to check out the panel.

Quote:
Originally Posted by 220/221 View Post
Remove the first non working recep or the last working one on that circuit. The circuit relies on a connesction built into the receps and they have a tendency to fail when they are connected via the backstab rather than the side screw terminals. The bad connection could be anywhere between the recep and the panel but generally the culprit is in a recep.
No backstabbing on any of the outlets, but after work I'll have to work my way around all of the nine outlets to check for connection rigidity...

Again, thank you to ALL!

p.s. even got out one of those cheapo, three-light plug-type outlet testers: bright orange on the hot wire, flickering duller orange on the neutral - guess that's what 11V looks like
dumbo is offline   Reply With Quote
Old 02-09-2009, 12:03 PM   #7
Member
 
Join Date: Oct 2007
Posts: 2,294
Rewards Points: 1,000
Default

120V between black/ground wire but ONLY 11-12V between black/white???


Quote:
I just don't understand what could be going on there: corrosion, loose connection?
There are connections at most every single recep and switch box. Things fail, especially receps.





Quote:
And how could that be related to plugging a radio into an outlet, and that little spark/flash I saw?
Check that recep first.



Quote:
Since that point the whole circuit is indicating this open neutral...

Are you sure the whole circuit is out??? Turn off the breaker in question and see if anything else goes off. Often the issue is in the last working recep.
220/221 is offline   Reply With Quote
Old 02-09-2009, 02:10 PM   #8
Member
 
joed's Avatar
 
Join Date: Mar 2005
Location: Welland, Ontario
Posts: 8,359
Rewards Points: 3,512
Blog Entries: 4
Default

120V between black/ground wire but ONLY 11-12V between black/white???


If the entire circuit is dead the I would open the panel and look for a loose neutral wire in the neutral bus.
joed is online now   Reply With Quote
Old 02-09-2009, 04:18 PM   #9
Newbie
 
Join Date: Feb 2009
Location: Indiana
Posts: 5
Rewards Points: 10
Default

120V between black/ground wire but ONLY 11-12V between black/white???


I really appreciate all of your input, and I finally got around to checking out the circuit panel - it's been a real learning experience. It's the first time I ever posted on the net, and was pleasantly surprised by the rapid and conscientious responses of you all.

After throwing the main breaker, I focused in on the neutral bus bar, and noticed that some of the screws were locking down 2 wires, so I started in on those first. None of them were what I would call loose - in fact, without some way of measuring torque, I wasn't going to go beyond the subjective impression of "hey, that screw ain't gonna' turn any more" - but one of them did give about 1/8+ of a turn... all of the single held wires were solid.

Well, after getting the panel back on, setting the main breaker ON as well as all the subsidiary breakers, I was greeted by power on the affected circuit...

Though the circuit is back to function, and other than finding it merely coincidental, is that all it might have taken to bring this circuit back on line? Having worked a lot with electronic equipment, one would never have needed that kind of pressure to get WATTS flowing from an amplifier to a speaker with stranded copper wire... is this the way it is with VOLTS and solid copper? Could that extra tension have "bit" into the copper sufficiently to once again complete the circuit?

I'm almost tempted to de-energize the panel again and spray some quick-dry contact/deoxidizing cleaner on the neutral bus...

Nahhhh: I better leave well enough alone!

Once again, thank you very, VERY much.
dumbo is offline   Reply With Quote
Old 02-09-2009, 04:56 PM   #10
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Rewards Points: 2,000
Default

120V between black/ground wire but ONLY 11-12V between black/white???


Loose connection = high impedance at the contact interface.

It should have gotten hot when you tried to pull current through it but the busbar conducts heat pretty well.
Yoyizit is offline   Reply With Quote
Old 02-09-2009, 06:41 PM   #11
Member
 
joed's Avatar
 
Join Date: Mar 2005
Location: Welland, Ontario
Posts: 8,359
Rewards Points: 3,512
Blog Entries: 4
Default

120V between black/ground wire but ONLY 11-12V between black/white???


By code there is only supposed to be one neutral wire per lug. That 1/8 turn could have been all it took. The wire could have been partially corroded or oxidized and the turn fix it.
joed is online now   Reply With Quote
Old 02-10-2009, 04:46 PM   #12
Newbie
 
Join Date: Feb 2009
Location: Indiana
Posts: 5
Rewards Points: 10
Default

120V between black/ground wire but ONLY 11-12V between black/white???


Quote:
Originally Posted by joed View Post
By code there is only supposed to be one neutral wire per lug.
Would that include a ground too, i.e. a ground and neutral under the same lug?

I'd have to check behind the breaker panel again to see what the combos were, but there are two bus bars - one on either side of the breakers - and there were grounds and neutrals attached to each of them.

Wouldn't surprise me if it wasn't code... there have been other things we've found in our short home ownership... amazing what a home inspection doesn't turn up AND what passed inspection when the home was first built almost ten years ago!

Quote:
That 1/8 turn could have been all it took. The wire could have been partially corroded or oxidized and the turn fix it.
AMAZING, given the power of all of those volts... as I said earlier, this has been a learning experience... thank you.
dumbo is offline   Reply With Quote
Old 02-10-2009, 05:02 PM   #13
Member
 
Join Date: Feb 2009
Location: British Columbia, Canada
Posts: 68
Rewards Points: 75
Default

120V between black/ground wire but ONLY 11-12V between black/white???


Ground and neutral bar are interchangeable in the service entrance (main) panel since they are tied together.
Should only be one neutral wire per connector, grounds can be more than one but how many I think depends on the panel manufacturer.
rovers1973 is offline   Reply With Quote
Old 02-10-2009, 06:03 PM   #14
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Rewards Points: 2,000
Default

120V between black/ground wire but ONLY 11-12V between black/white???


Quote:
Originally Posted by dumbo View Post
amazing what a home inspection doesn't turn up
The horns of their dilemma is
killing the real estate agent's deal
vs.
getting sued for wrongful death.

Kilobucks worth of landscaping to solve a drainage problem that they should have told me about does not meet this standard.

No real estate agent wants a customer who is
a civil engineer,
an attorney,
and is vengeful.
Yoyizit is offline   Reply With Quote
Old 02-10-2009, 11:21 PM   #15
Member
 
joed's Avatar
 
Join Date: Mar 2005
Location: Welland, Ontario
Posts: 8,359
Rewards Points: 3,512
Blog Entries: 4
Default

120V between black/ground wire but ONLY 11-12V between black/white???


Double neutrals is a code violation however it is not serious to have two under one lug. It is only a hazard when you attempt to remove one neutral and the other circuit is still energized. It could be a shock hazard.

Advertisement

joed is online now   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
New Stove, old wires - 2 wire vs 3 wire DIYGST Electrical 22 03-02-2009 05:13 PM
hooking up dryer....bronx ny code SURFBUG Appliances 6 10-14-2008 10:41 PM
Dryer Grounding??? Traci_howdyadothat Electrical 7 05-27-2008 02:14 PM
Installing Fluorescents in Garage rzrbkpk Electrical 26 04-08-2008 10:00 PM
Stranded wire on screw connections BigJimmy Electrical 7 01-19-2008 03:42 PM




Top of Page | View New Posts