help solve this mystery


Old 02-22-06, 06:28 AM
Thread Starter
Join Date: Nov 2004
Location: xxx
Posts: 310
help solve this mystery

Got back-to-back wall 110vac outlets. Let's call 'em outlets 1A/1B, and 2A/2B.

Presumably, these are fed by a common wire.

1A/1B have been in daily use for several years. Don't know when 2A or 2B were last used.

Yesterday, 1A/1B, and 2A were found dead. How can this be? I thought if 2A were dead, 2B would have to be dead also. But, it's still hot.

How could 1A/1B be dead, with 2A dead? What could have caused that combination of outlets to suddenly go dead?

I'm fixing to troubleshoot, and need to know what to look for (yes, I have the little neon glow testers and a multimeter). I'd like to have some idea of what to expect. Right now I have none.
Sponsored Links
Old 02-22-06, 06:48 AM
Join Date: Sep 2000
Location: United States
Posts: 18,497
I'm not sure whether 1A/1B are meant to indicate back-to-back receptacles (i.e., in room "A" and room "B") or are meant to indicate two receptacles in the room "1" (backed by 2A/2B in room "2"). Let me guess that "A" and "B" are the rooms, and that "1" and "2" the receptacles in the same room, rather than vice versa.

Your presumption that these are fed by a common wire is probably right, but not for sure.

If all of a circuit goes out, we usually suspect the breaker. If part of a circuit goes out, we usually suspect a failed connection, or a tripped GFCI. In your case, it's probably a failed backstab connection.

I suggest you spend $8 at your home center on an outlet tester, the kind that plugs in and has three lights. You can solve this problem without it, but the tester will narrow down what you're looking for. You can simulate the effect of this tester with your neon tester if you want. On each half of each of the four receptacles, make all three possible measurements (slit to slit, long slit to grounding hole, short slit to grounding hole). Post back with the results. Note that I just asked you to conduct 24 tests, so I expect 24 results, precisely tabluated. Keep a record as you conduct the tests.

By the way, your problem is not mysterious at all. It's extremely common.
Old 02-22-06, 07:57 AM
Join Date: Aug 2005
Location: USA
Posts: 995
I am thinking that A and B are the two receptacles of a duplex, with "1" on one side of the wall and "2" on the other side, both being duplex receptacles.

I would say that "2" is a half-switched or otherwise split receptacle. If you take it out of the wall, you should find that tab that joins the two together on the hot side will be broken and each screw will have a separate hot feed. 2A is likely a constant hot that is common with the circuit that feeds 1A/1B.

Is "2" a switched receptacle in that room?
Old 02-22-06, 08:02 AM
Join Date: Sep 2000
Location: United States
Posts: 18,497
Your interpretation is probably right Mac. If true, I only asked for 12 tests instead of 24.

The other thing to check, of course, is to see if there is a wall switch controlling any of this. Perhaps all you need to do is turn the wall switch on.
Old 02-22-06, 08:03 AM
bolide's Avatar
Join Date: Jan 2006
Location: PA
Posts: 1,909
Besides switching, are the wires to 2A or 2B backstabbed?
Old 02-23-06, 07:41 PM
Banned. Rule And/Or Policy Violation
Join Date: Feb 2006
Location: North of Boston, MA.
Posts: 2,113
Could be a broken neutral @ 2-b. start there. then work your way back from the others.

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