Confusing Receptacle Wiring

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  #1  
Old 01-04-15, 01:49 PM
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Confusing Receptacle Wiring

Just bought a house in MA built in the early 80s.

Updating some receptacles to decora with tamper proof slots.

Two questions I'm hoping someone can help with...

1)
I'm finding some receptacles that use the screw-in connectors AND the push-in connectors. Essentially taking the 1 load and relaying it to 2 other wires (rather than just 1). Is this OK? (my guess is they should have been pigtailed in the box...)


2)
In one room I found a receptacle with 2 of 14/2 wires coming in (lets call them A & B).
The black load wire from A (one with 120V) was pigtailed to the white wire from B and a short black wire that went to the receptacle.
The white wire from A went to the receptacle.
The black wire from B went to the receptacle also.
So it appears this setup was sending 120V through both the Black and White wires of the B 14/2 wire.
Any ideas what this may have been done for?

I'm speaking past tense, because I could not find what was downstream from this receptacle. So I completely disconnected the B wire from the receptacle and everything seems to still work fine in my house (so far one day later...)

Thanks!
 
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  #2  
Old 01-04-15, 02:09 PM
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1)
I'm finding some receptacles that use the screw-in connectors AND the push-in connectors. Essentially taking the 1 load and relaying it to 2 other wires (rather than just 1). Is this OK? (my guess is they should have been pigtailed in the box...)
Yes, best practice they should have been pigtailed both to avoid confusion if the receptacle is swapped out and because back stabs are less reliable then screws.
2)
In one room I found a receptacle with 2 of 14/2 wires coming in (lets call them A & B).
The black load wire from A (one with 120V) was pigtailed to the white wire from B and a short black wire that went to the receptacle.
The white wire from A went to the receptacle.
The black wire from B went to the receptacle also.
If I followed that it is a switch loop. The white of the switch loop cable by code should have been remarked black or red or any color but gray or green (or white it was) on both ends.
 
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Old 01-04-15, 04:42 PM
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If I followed that it is a switch loop. The white of the switch loop cable by code should have been remarked black or red or any color but gray or green (or white it was) on both ends.
Meaning.............the receptacle was probably switched. If you check, I think you'll find a switch with just one 14-2 cable coming into the box with 1 black and 1 white connected to the switch.
 
  #4  
Old 01-04-15, 07:58 PM
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Thanks! What both of you said makes sense.

I checked the old outlets I removed and one did have the load side tab pulled off, so supports the switch loop idea. (assuming it was from that outlet).

There is no extra switch anywhere and both outlets (top/bottom) were live prior to me removing the wires.

I'm guessing it was operated by a switch at some point, but someone removed the switch from the circuit and tied the wires together to prematurely power the outlet.
If this is true, I should find a black and white wire tied together in a box...somewhere.
 
  #5  
Old 01-04-15, 08:09 PM
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I checked the old outlets I removed and one did have the load side tab pulled off
Load side? Did you mean the HOT side tab or the tab on the BRASS SCREW side? Does the room have a ceiling light?
 
  #6  
Old 01-04-15, 08:47 PM
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Yes, HOT side tab was removed (right side). So this separated the two outlets (top/bottom).

The room has 2 sets of recessed ceiling lights. Not sure if both are original though.

Possibly... they are not original and when the house was built they used a switched outlet for the light (and code). Seems very common around here to have switched controlled outlets, rather than installed ceiling lights.
 
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Old 01-05-15, 07:31 AM
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I didn't study this thread in depth, but generally speaking:

You said there is no extra switch, but I assume there's a switch for the can lights.

It sounds like what happened was this: The outlet was previously switched. Previous owners took power from this outlet rather than switching it. The power was then ran up to the can lights.
This is an easy way to add ceiling lights from a switched outlet, as you only need to run one cable up into ceiling, rather than a cable to both switch and lights.
 
  #8  
Old 01-08-15, 07:07 AM
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Any statement of what the B cable used to be used for is pure speculation for now.

As you first saw it, both the black and white of the B cable were tied to the black of the A cable (raw hot) and also to the receptacle (I trust gold screw). That left no conductor in the B cable for a neutral or for a switched hot. At that instant, the B cable setup had no socially redeeming value.

You disconnected both the black and white of the B cable and curled them up in the box and you discovered no adverse consequences. Even if you did find something dead that use to be live, you may not reconnect it back the way it was. For that (hypothetical for now) dead item would have received hot from the subject receptacle and used neutral from somewhere else, which is a no-no.

The B cable could ultimately be used to continue hot and neutral to something else. But you may not reconnect it (white to A white and black to A black) without first finding its other end and verifying that the black and white were not tied to each other.

Neutral must accompany the corresponding hot at all times. An exception is in a switch loop. While the latest code requires neutral in a switch loop, that neutral is a single white conductor to serve loads such as dimmer switch electronics in or beyond the switch loop. The neutral path that serves the light or other load controlled by the switch loop does not go down and come back through the switch loop as two white conductors.
 

Last edited by AllanJ; 01-08-15 at 07:26 AM.
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