What’s behind my wall? 🤔

Reply

  #1  
Old 06-02-19, 11:43 PM
Member
Thread Starter
Join Date: May 2006
Location: Dallas, TX USA
Posts: 37
What’s behind my wall? 🤔

When I installed AFCI in my in-process remodel, I only had trouble with two circuits.

One of them was a 20A receptacle circuit in my kitchen nook. It powered three receptacles, and as far as I could test when I mapped my whole system, nothing else.

The AFCI would trip as soon as I flipped it on, so I checked the receptacles and one of those plug-in testers indicated “reversed hot/neutral”. The second receptacle I opened up had a random 14/2 wire attached (on a 20A circuit *smh*), that simply went through the side of the box and into the wall. When I pull/move the wire, it is definitely attached to something hanging lose inside the wall (I can hear it bang around in the wall).

As soon as I disconnected the random wire, the breaker worked as it should and the outlet plug-in tester showed all normal. The other side of the wall is the inside of a pantry, where there are no receptacles, fixtures or switches. The only thing I can think of is the old hardwired doorbell (long gone by now), which was mounted on the other side of the wall next to the pantry.

Could what I hear in the wall be the doorbell transformer? If so, how was it wired that would cause the AFCI to trip and the outlet tester to show reversed hot/neutral?? If not the doorbell transformer, any ideas based on anyone else’s experience?

I’m planning on capping off that cable and leaving it in the box until I renovate the kitchen next year (it’s not energized, but it still seems better to leave it in the box than just push it into the wall). I would love to understand especially what was causing the hot/neutral reverse.
 
Sponsored Links
  #2  
Old 06-03-19, 04:39 AM
Member
Join Date: Oct 2015
Location: Ct.,USA
Posts: 1,034
Likes Received: 13
Problem with the random 14/2 wire could be anywhere from the connection to the outlet to connection to the load (assuming there is one). Is the random 14/2 cable too short to connect directly to the outlet so the smh connector was used instead of wirenuts? I would tag the random 14/2 cable as defective until you can remove it. Outlet tester needs hot, neutral and ground connection to work. If the AFCI tripped immediately. it removed the hot connection so the outlet tester is without one of three inputs needed to make decisions and makes weird decisions. A analog multimeter is a better device to measure voltage for outlet reverse wiring.
 
  #3  
Old 06-03-19, 05:24 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,866
Likes Received: 22
I agree with tagging it out until you can find the other end. You can't safely cut it off and stuff it in the wall until you're confident the other end can't be energized by another circuit.

A doorbell transformer is usually mounted to a junction box cover, but it's possible someone buried one in the wall. The clunking noise is probably just the unfastened cable thumping against the drywall. My first guess for mystery 14-2 wires in a kitchen is poor installation of undercabinet lighting.

Hot/neutral reverse is often actually an open ground. The bug style tester can't tell the difference.
 
  #4  
Old 06-03-19, 05:33 AM
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 6,305
Likes Received: 31
It could be anything.
A junction box that was stuffed inside the wall.
A wad of tape over the bare wires.
A coil wire that was going to be used for something.
 
  #5  
Old 06-03-19, 08:38 PM
Member
Thread Starter
Join Date: May 2006
Location: Dallas, TX USA
Posts: 37
Kind of what I was thinking as well. There is definitely a metal box/device in the wall (I can hear the metallic sound when it clunks against the wall), but that could obviously just be an old junction box that someone put inside the wall.

Good point about the plug-in tester being useless in this scenario.

The 14/2 was connected directly to the outlet. I have capped in and left it in the box for now. Once I get a chance to see the other end of that wire I guess I will find out what it was for :-)
 
  #6  
Old 06-03-19, 08:40 PM
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 6,305
Likes Received: 31
You can't use the 14/2 on a 20 amp circuit.
 
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