Help Please

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muckusmc

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Roebling, NJ
Service call to townhouse - voltage reading 120/240 with all breakers in panel off - reading 3-45 ph A, 215-255 with breakers on - thought neutral problem - replaced feeder from main distribution to sub panel in townhouse. Did not fix problem. Did find bad wire in kitchen circuit - replaced same - cleared that problem, however, still have problem as other circuits are turned on - jumper between ground and neutral, problem goes away - any ideas???
 
muckusmc said:
jumper between ground and neutral, problem goes away - any ideas???
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What's your reading between neutral and ground at the panel ( with jumper removed )? I don't know the distance of this feeder but if the neutral and ground are bonded at the main this resistance should be very low. If it's not you still have a bad neutral connection ( or they are not bonded at the main).

I would make sure that everything is good back at the main disconnect before anything else and then work my way forward.
 
neutral/ground is good at distribution and at panel without any branch circuits turned on. 2 pole branch circuits have no effect - only the single pole breakers. We have removed all switches and receptacles and everything looks good except for the weird voltage readings.
 
muckusmc said:
neutral/ground is good at distribution and at panel without any branch circuits turned on. 2 pole branch circuits have no effect - only the single pole breakers. We have removed all switches and receptacles and everything looks good except for the weird voltage readings.
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The two pole breakers would work fine even if the neutral was missing from the panel. So don't worry about them.

If this problem is on all single pole circuits then you still have a bad neutral connection. Measure the resistance from neutral to ground at the distribution panel and then measure resisitance from neutral bar to ground at the panel. I don't know where you are losing it, it could be at the lug where the neutral conductor mounts to the neutral bar ( if the connection is either lose or corroded). There has to be some resistance there some place otherwise that jumper from neutral to ground wouldn't have made any differrence.
 
That's what is driving me nuts - it is not on all the single pole circuits - panel is laid out with all single poles on right hand side - 2,4 read 120 volt to neutral - 6 reads 103 volts - 8,10,12 reads 235-240
 
muckusmc said:
That's what is driving me nuts - it is not on all the single pole circuits - panel is laid out with all single poles on right hand side - 2,4 read 120 volt to neutral - 6 reads 103 volts - 8,10,12 reads 235-240
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have you checked all connections? did you tighten everything? check voltage at the meter socket and see whats there. having different voltages in the same panel doesnt make sense unless something is loose
 
muckusmc said:
That's what is driving me nuts - it is not on all the single pole circuits - panel is laid out with all single poles on right hand side - 2,4 read 120 volt to neutral - 6 reads 103 volts - 8,10,12 reads 235-240
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Are 6,8,10,12 3 wire circuits?
 
only thing we haven't checked is the light fixtures.
found out just before leaving for the day that the tenant had installed their own fixtures. will have to check them on the return trip and see what i find then - will let you know - thanks - bed time for these old bones
 
muckusmc said:
That's what is driving me nuts - it is not on all the single pole circuits - panel is laid out with all single poles on right hand side - 2,4 read 120 volt to neutral - 6 reads 103 volts - 8,10,12 reads 235-240
Click to expand...

How are taking these readings? With all the circuits on? Do they all have loads? What is the total load on each incoming leg?
 
muckusmc said:
That's what is driving me nuts - it is not on all the single pole circuits - panel is laid out with all single poles on right hand side - 2,4 read 120 volt to neutral - 6 reads 103 volts - 8,10,12 reads 235-240
Click to expand...

I would start to trouble shoot all over again as if this were a fresh problem. Get a not pad and write down the reading. The only thing I can think of right off is that you may have changed where you were making contact with the neutral ( the meter lead ).

I must admit this is kind of weird. Unless the panel is fried you should get the same on all A phase breakers all the way down and the same on all B phase breakers ( with all breakers on and working it's the same point ).

The only reason I can think of for reading over 200 volts on one leg is a missing neutral which changes things from a parallel to series circuit or a really flakey meter.

You could try taking all conductors loose from the single pole breakers and then turning them on one at a time to see if everything at the panel still measures the same.

You need to isolate the problem down to a certain area and not try to trouble shoot the whole house or building.

Lots of luck.:smile: :smile:

I like to tell people that my head is not naturally bald I pulled all the hair out trying to solve difficult problems but I have never failed to solve one I just lose a little more hair from time to time. :grin: :grin:
 
Jim W in Tampa said:
You need a load on each circuit 1 at a time with all other breakers off.Is panel by chance a split bar system ?
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That's the same question that popped into my head.

steve
 
muckusmc said:
thanks for all the input guys - poco is suppose to be out tomorrow to unlock the meter - will let you know what i find - again thanks
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They move kinda slow there.If it is a neutral problem there is a high fire risk here.They should have treated this as a 911
 
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