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single outlet with each plug on different circuit - shared neutral??

single outlet with each plug on different circuit - shared neutral??

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  #1  
Old 01-06-12, 07:55 AM
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Question single outlet with each plug on different circuit - shared neutral??

on one wall of my condo, the outlets are wired such that the top plug is on one 15amp circuit and the bottom plug is on another 15amp circuit.

the bottom plug is switched (eg, expected that lights would be plugged into the bottom outlet) - and the top is always live (no switch).

i was rewiring some of this such that the plugs are on a SINGLE circuit (and the bottom/switched circuit is out of the equation - so id basically disconnect and cap off the hot wire for the bottom plug).

in doing this, i discovered that there appears to be a SINGLE neutral wire servicing both plugs on the outlet - and then separate HOT wires for each circuit for the top and bottom plug in the outlet.

is there supposed to be a separate neutral for each circuit when sharing an outlet like this?? or can they share neutral? what happens when im using 10amps from EACH circuit in the outlet?
 
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  #2  
Old 01-06-12, 09:11 AM
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is there supposed to be a separate neutral for each circuit when sharing an outlet like this?? or can they share neutral? what happens when im using 10amps from EACH circuit in the outlet?
As long as they are on a 240v 2 pole breaker no problem. If they are on very old wiring with two 120v breakers (no longer code) the breakers must be on opposite legs of the incoming 240v supply.
 
  #3  
Old 01-06-12, 11:08 AM
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building was new / opened in 2000 - so relatively new wiring. no idea what the breaker is but i can investigate. thank you,
 
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Old 01-06-12, 12:03 PM
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You don't know what the breaker is? Didn't you turn it off before you worked on this circuit?
 
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Old 01-06-12, 06:24 PM
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Are you saying the top part of the outlet has a different breaker than the bottom part?
 
  #6  
Old 01-07-12, 01:49 PM
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You may just be dealing with a single circuit with both a switched and a constant hot. This is the most likely situation.
 
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Old 01-07-12, 03:32 PM
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there are two (2) separate 15amp circuits. one circuit is terminated at the top plug of the outlet, and the other circuit is terminated on the bottom plug of the outlet.

the bottom plug (circuit) is switched (for lights that i plug in), and the top plug (circuit) is a separate (constantly on, unswitched) 15amp circuit. there are 2 breakers (one for the circuit terminating the top plug, and another for the circuit terminating the bottom plug). so it is not a shared circuit.

i dont have any lights being used on the switched circuit, so im basically disconnecting (and capping off) the hot wire on the bottom plug of the outlet (that is switched), and modifying such that the unswitched (always on) circuit is feeding BOTH plugs in the outlet - taking the switched circuit out of the equation entirely (since it is not used).

when i was investigating (i havent performed this work yet), i noticed that there was circuit-1 hot wire connecting to the top plug, and circuit-2 hot wire connecting to the bottom plug - but it seemed like there was a single neutral wire feeding both plugs of the outlet. i could be wrong i will investigate again tomorrow and remove the plug to verify - but i was just curious of there would ever be a reason when a shared neutral is used in such a scenario.

here is a photo of one of the breakers for one of the circuits in this scenario - both breakers for this outlet are identical:

http://i.imgur.com/Xttli.jpg

<img src="http://i.imgur.com/Xttli.jpg">
 
  #8  
Old 01-07-12, 05:05 PM
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Ok, thanks for adding that there are actually 2 breakers.

What you are dealing with is called a multiwire branch circuit. The breaker should have been a two pole since both hots are on the same yoke.
 
  #9  
Old 01-09-12, 11:53 AM
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Originally Posted by pcboss View Post
Ok, thanks for adding that there are actually 2 breakers.

What you are dealing with is called a multiwire branch circuit. The breaker should have been a two pole since both hots are on the same yoke.
thanks.
im essentially taking the switched circuit out of the equation - and then will have a single (unswitched) 15amp circuit powering both plugs in the outlet...so no reason to swap out the breakers with two-pole since the current scenario will not be used going forward.
 
  #10  
Old 01-09-12, 01:00 PM
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The electrical code requires a switch controlled lighting outlet in habitable rooms. You sound like you are creating a code violation by removing the switch controlled outlets.
 
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Old 01-09-12, 02:26 PM
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"The electrical code requires a switch controlled lighting outlet in habitable rooms."

My living room is wired like this (well, was - I hardwired that receptacle several years ago) but no other rooms in the house - does the code dictate a switched receptacle in each habitable room or would a switched ceiling fixture suffice?
 
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Old 01-09-12, 04:14 PM
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The key here is lighting outlet. A ceiling mounted fixture would satisfy the requirement.

The requirement uses the NEC definition of outlet, not receptacle outlet.
 
  #13  
Old 01-10-12, 01:40 PM
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Originally Posted by pcboss View Post
The electrical code requires a switch controlled lighting outlet in habitable rooms. You sound like you are creating a code violation by removing the switch controlled outlets.
my apartment is a single (large) room, loft-space type studio. there are light switches for entrance and main lights --- the switch i removed was for other outlets of which are not being used for lights. i require that circuit to be "always on" and didn't want anyone accidentally flipping that switch so i removed it entirely.
 
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