Connecting to box triggers hot/neutral reverse

Reply

  #1  
Old 09-06-12, 09:40 AM
Member
Thread Starter
Join Date: May 2012
Posts: 19
Connecting to box triggers hot/neutral reverse

This is baffling. All the outlets in the upstairs of this house test hot/neutral reverse. So I pull all of them out of the wall and check the wiring to find if they are all wired correctly, ie the black wire to the hot/brass side. They all look fine. I checked an outlet while it is hanging out of the box and suddenly it tests normal. The moment the outlet mounting screws touches the metal box the outlet again tests hot/neutral reverse. How can the mere contact with the box change the reading?

The other thing strange about the outlets in this room is that when I put a wand style electric tester within an inch of the outlet it starts to beep. Normally I have to insert it into the hot slot to make it beep. In this room the tester beeps by merely waving the wand anywhere near the whole box. What is going on here?
 
Sponsored Links
  #2  
Old 09-06-12, 10:02 AM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,058
Please do not format your posts with small font. Lucky for you I am a mod and could remove it otherwise I would have skipped your post as to hard too read.

It sounds like you are using a plug-in tester. They do not always give an accurate diagnosis. You need to use a multimeter, preferably analog. Measure from neutral (wide slot) to ground. It should less then 5 volts. Measure from the hot (narrow blade) to ground. It should be about 120 volts. Measure hot to neutral that should be ~120v.

when I put a wand style electric tester within an inch of the outlet it starts to beep.
Their useless for any kind of serious testing. Their results and five dollars will get you a cup of coffee at Starbucks.
 
  #3  
Old 09-06-12, 10:22 AM
Member
Thread Starter
Join Date: May 2012
Posts: 19
Thank you for your answer. I forgot to mention that this is an old house and it only has two wire cable without ground. The other outlets on this circuit downstairs all test open ground which is fine. Yes I did use a plug in tester, but that is what the inspector used. I have to make these outlets pass his inspection. I know most electricians do not like the wand tester, but it concerns me that ONLY in this room do I just merely pass the wand near the outlet and I get a reading.

Why would just merely touching the outlet to the box cause this? I guess I could replace the metal boxes with plastic, but I want to fix what is wrong.
 
  #4  
Old 09-06-12, 10:32 AM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,058
The non-contact tester measures the presence of electromagnetic non-ionizing radiation. All alternating current in unshielded cable has some radiation.

Even a 2-wire circuit may be grounded if it is wired with conduit, metallic cable, or was wired with the ground connected to the outside of the box during the early days of non metallic grounded cable.

Bottom mine the first step is to use an analog multimeter or a good quality digital meter that rejects most inducted voltage.
 
  #5  
Old 09-06-12, 10:39 AM
Member
Thread Starter
Join Date: May 2012
Posts: 19
I have a Sperry DSA 500 meter and my dad's old Simpson meter. I am not real sure how to use them for what you are saying. Since I do not have a ground wire how am I to do this? How do I fix the outlets so they register just open ground iinstead of hot/neutral reversed? Thank you for your patience.
 
  #6  
Old 09-06-12, 12:50 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
this is an old house and it only has two wire cable without ground. The other outlets on this circuit downstairs all test open ground which is fine... How do I fix the outlets so they register just open ground iinstead of hot/neutral reversed?
If you have three-slot receptacles on a two-wire system, and there is no ground, that is a code violation because it is dangerous.

Test for 120V AC from a hot wire to one of the metal boxes. There may be a ground made by the cable, or connected outside the box.

If you still find no ground, there are three ways of correcting this:
  1. Replace all of the three-slot receptacles with two-slot receptacles;
  2. Run a new EGC (Equipment Grounding Conductor, or ground wire) from the panel to each outlet in each circuit; or
  3. Determine the first receptacle outlet in each circuit, from the panel, and replace that receptacle with a GFCI receptacle, and connect the incoming power to LINE and the outgoing feed to LOAD on the GFCI receptacle; use the stickers that come with the GFCI to label each of the downstream receptacles on each protected circuit "No Equipment Ground."
#1 is probably not attractive. #2 provides a ground, but can require a lot of difficult work. #3 provides a code-compliant alternative to having an EGC, and is often the easiest method.
 
  #7  
Old 09-06-12, 12:54 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
I have a Sperry DSA 500 meter and my dad's old Simpson meter. I am not real sure how to use them for what you are saying.
Set either meter to the smallest value that is greater than 120V, in the AC voltage section of the dial. With a receptacle removed and the power turned back on, touch one probe to each of the two wires. Then touch one probe to one wire and the metal box, then do the same with the other wire.

Post back with your results, and we can help you from there.
 
  #8  
Old 09-06-12, 01:16 PM
Member
Thread Starter
Join Date: May 2012
Posts: 19
I did not want to complicate this, but I have already put this entire circuit on a GFCI because they are not grounded. This part is fine with the inspector. However, the upstairs outlets are the only ones on the line to have this problem and he will not pass those that register hot/neutral reverse.
 
  #9  
Old 09-06-12, 01:27 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
Do you have any receptacles in the house, maybe on a circuit that was added later, that have a ground? If so, you can run a 3-wire extension cord from the closest one of those to where you are testing and use the ground slot in it for testing hot-to-ground and neutral-to-ground. Just stick one of your two probes into that slot.

But do test hot-to-box and neutral-to-box at a receptacle where you're seeing this reversal.
 
  #10  
Old 09-06-12, 06:39 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,397
While doing your sleuthing, check closely to see if a ground wire was connected to the outside of the metal boxes. If so, I think it might be possibloe to confuse a plug-in tester if the ground wire was actually connected to a bootleg; meaning it could have been connected to the neutral conductor somewhere instead of running back to a ground bar in the service panel.
 
  #11  
Old 09-06-12, 08:39 PM
Member
Thread Starter
Join Date: May 2012
Posts: 19
My meter only has a 600 V setting. When I measure the balck and white power in wires it is 92.6. The two wires going downstream measure 18.4. I dont know why they measure anything. When I measure the power in black wire and the box it is 17.3. Power in white wire and box is 2.4.


Just to see what would happen I joined a ground wire to the box and the green screw on the outlet and the outlet then tested hot/neutral reveresed when it was in or out of the box. I guess that is consistent.
 
  #12  
Old 09-06-12, 08:47 PM
Member
Thread Starter
Join Date: May 2012
Posts: 19
Nashkat there are some switches upstairs. One is a singlepole switch and the other two are three pole. When I tested one switch on the bottom of the stairs and the one at the top they did not work right. It seems that if you turned the lights on with the downstairs switch you could turn it off upstairs, but you could not turn it on again without using the downstairs. Then it seemed to switch the opposite way. Tomorrow I want to open theseswitches to see why. Would that cause my hot/neutral reversal problem or isthat a separate issue?
 
  #13  
Old 09-06-12, 08:59 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,058
that is a separate issue and they are not 3-pole they are single pole three way switches (SPDT). There are three terminals (and ground if a newer switch). Two of the terminals are the travelers and the other, usually black, is the common. Position of the travelers on the two brass screws doesn't matter but if you get one of the travelers on the common and the common on one of the traveler screws you will get symptoms similar to what you describe but for now lets start testing as explained above to determine the reason for the hot neutral reverse.
 
  #14  
Old 09-07-12, 08:08 AM
Member
Thread Starter
Join Date: May 2012
Posts: 19
In post 11 I gave the numbers requested. What is your opinion?
 
  #15  
Old 09-07-12, 12:36 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,058
Sorry missed post #11. The meter is apparently digital. Is the other an older Simpson analog meter (has a needle). If so do your tests again with it. The readings look wrong. Like a digital that isn't rejecting induced voltages are needs its batteries changed.
 
  #16  
Old 09-07-12, 08:04 PM
Member
Thread Starter
Join Date: May 2012
Posts: 19
This circuit starts out in the main circuit breaker as an old two wire cable without ground. I did not notice till today thatthe new wire used in these outlets does have a ground wire . Downstairs on a three way switch some idiot attached that ground wire to the black hotscrew on the switch. One thing I did learn from this is that there was indeed a reason my wand went crazy in that room. The boxes were obviously all hot so it immediately sounded when it came within an inch of a box. Thanks all for the help. The outlets now all test fine and to find if the outlet is hot I have to put the wand all the way in the slot to get a reading.


By the way, I write these posts using Word, but the font is small when I get it here even though I use size 14 in Word.
 

Last edited by Nashkat1; 09-07-12 at 08:41 PM. Reason: To remove font designation.
  #17  
Old 09-07-12, 08:49 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
Thank you for the feedback about your non-contact voltage tester.

Where are we on the hot/neutral reverse question?

By the way, I write these posts using Word, but the font is small when I get it here even though I use size 14 in Word.
And you could edit your posts to remove the font designation as easily as one of can. Not only that, your doing that would mean that the posts would be legible from the moment they are posted, rather than remaining small until one of us catches and corrects them.
 
  #18  
Old 09-08-12, 08:07 AM
Member
Thread Starter
Join Date: May 2012
Posts: 19
The hot/neutral issue is resolved since I found that some prior owner had connected a ground wire to a hot screw on a three way switch. They probably saw the loose wire and thought it must go somewhere so why not put it on the first screw they saw. I lost two days figuring this out. Thanks for all your help.

I now see the editing menus at the top, but I do not see font size. I used the "paste from word" command. Is this font better?
 
  #19  
Old 09-08-12, 09:16 AM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,058
Glad you got it.

I would suggest no formatting. The forum will do it's own formatting. Why not use Firefox or Opera if you need spell check. Both have good easy to see in line spell check. Or use Composer in Seamonkey if you want a stand alone editor that lists your miss-spelled words. The font type affects size also. In the last post I edited it was the type of font that small. If you use Word compose as text not rich text or html.
 
Reply

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


Thread Tools
Search this Thread
Display Modes