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Discussion Starter · #1 ·
Single phase 3 wire 200 amp service. Everything seems normal. Properly bonded and grounded. But, L1 to neutral/gnd = 122.3 v, L2 to neutral/gnd = 122.9 v, and L1 to L2 = 241v. L1 carries about 1 amp more than L2 which shows up in the neutral like it should. Gnd carries no current.

What gives?
 

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Discussion Starter · #3 ·
Residential. Mostly resistive load. Maybe 1.5 hp at any given rime
 

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Hackenschmidt
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Is the service neutral reduced size?

Did you measure voltage with the main open?
 
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Discussion Starter · #6 ·
Is the service neutral reduced size?
Neutral is full sized on the customer side - can't speak for the powerco
Did you measure voltage with the main open?
Can't secure the whole service yet, but did secure all of the 240 v loads - same voltage disparity.

What are you thinking? Seems if the neutral were open (or weak) on the powerco side then the L1-N and L2-N voltages would vary more with load and they don't seem to. When I secured all of the 240v loads the L1 and L2 currents were different by a factor of 2, which should have given vastly different L-N voltages, methinks.
 

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Hackenschmidt
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Is the service neutral reduced size?
Neutral is full sized on the customer side - can't speak for the powerco
What are you thinking? Seems if the neutral were open (or weak) on the powerco side then the L1-N and L2-N voltages would vary more with load and they don't seem to. When I secured all of the 240v loads the L1 and L2 currents were different by a factor of 2, which should have given vastly different L-N voltages, methinks.
With an open neutral, the 240/120 turns into a series / parallel 240VAC circuit and the voltage L1-N and L2-N will fluctuate - the bigger the disparity in load on L1 and L2, the bigger the disparity, but they'll still add up to 240.

If the neutral return path is just higher resistance than normal (normal being just the resistance of the wire itself and good connections) it gets a little more complicated, more voltage drop in the wire, I can't quite connect the dots off the top of my head but it seems like you could wind up with unexpected voltages. It could be just where you were measuring on the neutral bar or where ever.
 
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I really don’t see what the problem is ? Maybe the house is the closest one to the transformer and the taps are set a tad high but even that’s a stretch. Also as more load is in the transformer the voltage will sag a bit. +or- 10%
 

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Discussion Starter · #11 ·
With an open neutral, the 240/120 turns into a series / parallel 240VAC circuit and the voltage L1-N and L2-N will fluctuate - the bigger the disparity in load on L1 and L2, the bigger the disparity, but they'll still add up to 240.

If the neutral return path is just higher resistance than normal (normal being just the resistance of the wire itself and good connections) it gets a little more complicated, more voltage drop in the wire, I can't quite connect the dots off the top of my head but it seems like you could wind up with unexpected voltages. It could be just where you were measuring on the neutral bar or where ever.
That's just it. The sum of the L1-N and L2-N voltages is greater than the L1-L2 voltage by 4 or 5 volts. And the L1-N and L2-N voltages don't vary given different loads. Can't come up with a way that explains all of this.
 

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That's just it. The sum of the L1-N and L2-N voltages is greater than the L1-L2 voltage by 4 or 5 volts. And the L1-N and L2-N voltages don't vary given different loads. Can't come up with a way that explains all of this.
It’s becuase your meter reads Volts RMS and this is an ac system Not dc so the sums won’t be exact
 

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Flukes self test. You will get a screen that will let you know if there is a problem.

Was hoping it was something decent not some HF freeby give away.
 

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Just trying to get home
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Been doing this for 50 years and never ran across a case where the sum of the L-N voltage exceeded the L-L.
You've been doing this for 50 years and you just joined ET?

What did the sparkies at Tradeworks say?
 

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Discussion Starter · #18 ·
You've been doing this for 50 years and you just joined ET?

What did the sparkies at Tradeworks say?
Never needed help before! (Ha!) Just discovered this site.

Cut my teeth in Chicago in the 60s converting buildings form DC to AC. You know, back when we had to climb to the top of a ladder with a little dip pot full of solder to make up splices. You know, messing up nice strait pieces of pipe up with a chicago bender, putting double locknuts and bushings on heavywall in 1900, 8B and 11b boxes, making up panels with barbers twine and clove hitches. Most of my time on industrial jobs. Quite a bit of time on Power Plants - coal nuclear and hydro. I know that comes out to more than 50 years, but I always just round to half a century, doesn't make me seem so old.

Satisfied?
 

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Never needed help before! (Ha!) Just discovered this site.

Cut my teeth in Chicago in the 60s converting buildings form DC to AC. You know, back when we had to climb to the top of a ladder with a little dip pot full of solder to make up splices. You know, messing up nice strait pieces of pipe up with a chicago bender, putting double locknuts and bushings on heavywall in 1900, 8B and 11b boxes, making up panels with barbers twine and clove hitches. Most of my time on industrial jobs. Quite a bit of time on Power Plants - coal nuclear and hydro. I know that comes out to more than 50 years, but I always just round to half a century, doesn't make me seem so old.

Satisfied?
wait one more did they even have meters 50 years ago ?
 

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If you have 2 sine waves 180 degrees out of sync then shift one forwards or backwards a tiny amount then adding L1 to N + L2 to N will not equal L1 + L2.

You could try removing all the loads then testing to see if you can get it closer.
 
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