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Can I move all 120 breakers to one of the 2 120 legs? (temp)

Can I move all 120 breakers to one of the 2 120 legs? (temp)

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  #1  
Old 10-31-12, 03:53 PM
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Can I move all 120 breakers to one of the 2 120 legs? (temp)

I lost one of the legs or phase if you will of my electric service in the storm, half the lights started to flicker and then browned out, I check the main coming in to the box and sure enough one was a rock solid 121V and the other was 70V or so depending on load, so actually it's a loose connection (I think it's corrosion at the drop connection on the utility pole since this happened before TWICE each time they say it was badly corroded connection.

So my question is until they get to this (could be next week) can I move 2 breakers from the bad phase to the good one and run everything off of the good leg or will this cause problems with the neutral taking a load? Of course none of the 220 appliances will work and I turned those breakers off.

As far as I can think this should be OK, just wanted to double check if moving those 2 120 breakers to the the good leg be safe?

I already moved the furnace to the one good leg (furnace was luckily only a 120) and all has been fine. (and I know the busbar I connect the breakers to is live even when I turn of the main off so I'm being really careful when I move a breaker)

Thanks
 
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  #2  
Old 10-31-12, 04:19 PM
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So my question is until they get to this (could be next week) can I move 2 breakers from the bad phase to the good one and run everything off of the good leg or will this cause problems with the neutral taking a load?
That should be fine. In fact, you can just rearrange your panel so that the two 120V circuits that you need to power up now are on the good leg and the other breakers are fitted in where there's space and leave it that way, even after the repair is made.

That is, unless any two of your 120V circuits are wired as a multiwire branch circuit. In a MWBC, the two hot wires share one neutral and, in those circuits, the two hots need to be fed from the two different legs. To avoid creating the problem that would result from supplying those from the same leg, trace the wires inside your panel to make sure that each of the circuits is connected to a 2-conductor cable, so that each hot wire has its own neutral.

Of course none of the 220 appliances will work and I turned those breakers off.
Right. It sounds like you're planning to leave those off until after the second leg is restored, which is probably wise - not sure what having 120V on only one leg of a single-phase 240V circuit would do to the loads, but it's hard to imagine that it would be good for them.

I know the busbar I connect the breakers to is live even when I turn of the main off so I'm being really careful when I move a breaker
Actually, turning the main breaker off should open the feed to the ungrounded buses and remove power to them. You can test with your meter to verify that. As for being really careful, yes, do that anyway!

JOC, have you tried turning the main breaker off and back on to see if that restores the power on the dropped leg? A long shot but, hey, if you don't try it you won't know.
 
  #3  
Old 10-31-12, 05:17 PM
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Thanks for the fast response! you lost me a second on the multiwire branch circuit, (now I learned something new) 2 breakers using one neutral and on different legs, interesting, so no I don't have any of those, not sure why someone would have that... and I'll go over the neutrals and trace each one to be 100% before moving:-)

Great, not sure where I picked up the whole using just one leg puts too much on the neutral, so had to double check to be sure it wasn't for any safety reasons I wasn't aware of.

Thanks!
 
  #4  
Old 10-31-12, 06:19 PM
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Multi-wire branch circuits are installed in residential buildings to save money. Less wire is used and often less labor. I personally think it is a false economy but no one has ever asked my opinion on the subject.

In commercial and industrial systems using three phase power there is a definite cost advantage.
 
  #5  
Old 10-31-12, 08:33 PM
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Great, not sure where I picked up the whole using just one leg puts too much on the neutral, so had to double check to be sure it wasn't for any safety reasons I wasn't aware of.
The neutral, or ungrounded, conductor carries the unbalanced load between the legs. For that reason, installing all of the 120V circuits on one leg loads a lot of power on the the common neutral.

240V circuits to not need or use a neutral conductor because the two legs are always in balance, so long as both legs are fully connected. Yours are not, at the moment, so that raises the question of whether the neutral might become overloaded. The answer is that that is very unlikely. So long as each 120V circuit contains its own neutral, those circuits are OK. The service neutral is sized for the cabinet and its loads, and should not become overloaded either.
 
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