Dead outlets with .4 volts

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  #1  
Old 12-04-19, 07:20 PM
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Dead outlets with .4 volts

So I have outlets and lights on a mwbc. A 15a dp feeds the lights and a 20a dp feeds the outlets. If I turn off both dp breakers, I get no voltage (obviously) but if I switch both on, the lights work and I get .4 volts (hot) .2 volts (neutral) at the outlets. If I switch just the 20a dp on, I get no lights (makes sense) but also nothing at the outlets.

That leads me to the conclusion that the .4 is bleeding over from the lights. I tested the breaker and its 120 on both legs, btw.

So 120 is leaving the panel and not making it to any of the outlets. Is the minimal voltage being carried by the shared neutral? Is this a neutral problem or a hot.. or both? If I've ruled out all the obvious stuff (damage at the outlets, switches, and neutral pigtails, panel) what's left to try?

I don't think there are any jb's unless they're hidden in the walls.
 
  #2  
Old 12-04-19, 08:14 PM
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You are using a high impedance digital meter. .4 volts is nothing. Grab the leads with both hands and see how many volts you have.
 
  #3  
Old 12-05-19, 07:31 AM
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Are you talking about two multiwire branch circuitss, one for the lights and one for the receptacles, or is it one MWBC, half for the lights and the other half for the receptacles?
 
  #4  
Old 12-05-19, 01:10 PM
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It's two separate MWBC's. A 15a for lights (red, black) and a 20a for outlets (red, black).

 
  #5  
Old 12-06-19, 10:42 AM
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I think you may be sharing the neutrals incorrectly. The two separate MWBC should be completely separate. The 15A MWBC should have B/R/W wires connected to the lights, and the 20A MWBC B/R/W wires connected to the receptacles. Anywhere that they end up in the same boxes, the neutrals should not be tied together.

It sounds like one of your circuits may have a floating neutral, and it's using the other neutral to come back on.

(All grounds are always tied together in any box, but don't affect the testing/operation)
 
  #6  
Old 12-08-19, 08:25 PM
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I think they may have wired the neutrals together at the back or front porch switch. I don't know if it was accidental or intentional but would the neutral account for all the outlets having no voltage? The breaker reads 120 on both legs, btw.

Most of the "open neutral" posts I've read have involved erratic voltage but not a total loss across the whole circuit.
 
  #7  
Old 12-10-19, 11:37 AM
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I would think it's actually two separate issues that are combining due to tied-together neutrals. It sounds like somewhere along the line, there's a loose wire for the receptacle circuit. That's its own problem that needs to be resolved.

But since the neutrals are tied together, you're getting weird readings and 'crossover' (my word, not a technical term) voltage because you have the two circuits incorrectly tied together. That's usually what happens with open neutrals - weird voltages in odd places.
 
 

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