2 hot, 1 return


  #1  
Old 11-18-03, 10:27 AM
ALU_in_MN
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Question 2 hot, 1 return

Six years ago, I purchased a 1970 Orrin Thompson home with aluminum wiring. Up until now, the only "really" unsafe stuff I've seen was done by the original owner. Usually it's been stuff like wirenutting copper to aluminum while he over-extended existing circuits. <sigh>

But while doing an inspection of an unmodified circuit during a remodeling project I noticed that there are two hot wires fed into the same conduit, but there is only 1 return wire. Inside the first outlet box that the conduit reaches, that one return wire is split and used for both circuits.

All three wires are #12 aluminum, and the wirenut on the return wire was warm to the touch.

I'm puzzled, tho. This wasn't a modified circuit, so I'm left wondering is there any way that this could have previously been considered "safe"?!?

The bedroom circuit is off until I consult with a professional electrician.
 

Last edited by ALU_in_MN; 11-18-03 at 01:09 PM.
  #2  
Old 11-18-03, 11:12 AM
ALU_in_MN
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OK. It's a simple shared-return circuit. Scary part was that the original owner moved the breaker to the same freakin' bus-bar as the other circuit, so the 1 return could have been taking 30 AMPs. Ouch.

Sorry for the noise.
 
  #3  
Old 11-18-03, 01:11 PM
ALU_in_MN
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Um. Looking at the box, the two circuits were already on different legs.

Any ideas on why that wirenut on the return side would have been warm when one of the circuits was off at the breaker?
 
  #4  
Old 11-18-03, 03:52 PM
J
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Why is it warm
Simple - It's aluminum wire. The connection is going bad. This is why you can't aluminum anymore for wiring your home. It is still used for feeder cables though.
 
  #5  
Old 11-18-03, 07:16 PM
S
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Warm because of a failing connection, but also because even though one was off, one was on and being used.
 
  #6  
Old 11-18-03, 08:04 PM
ALU_in_MN
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It's always good being human and _not_ being a better path to ground.

Given that the wiring on that nut didn't show any of the usual signs of overheating (it was still flexible and showed no browning on the insulation) I'm inclined to just put it on the "watch" list.

Do you think it needs more urgent attention?
 
  #7  
Old 11-20-03, 02:03 PM
rob1kva
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This is a split circuit. You are correct in saying the neutral is carrying 2X the load it should due to both breakers being on the same phase.If it were up to me I would replace the entire circuit.Ideal Industries does manufacture a Cu/Al wirenut for these connections but I never have used them.
 
 

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