Neutral Wire

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sharkeye

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We had a question ask in our office today about the neutral in a electrical panel. The young man asking the question stated that the neutral balances the load in a electrical panel, and some of our older electrian's said no it doesn't. so the young man took a two 120volt light bulbs and hooked in series applied 240volt to them and said you now have a balanced load and you don't need a neutral wire. and asked so whats the neutral for. Please settle the argument.
 

roger

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Fl
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Retired Electrician
We had a question ask in our office today about the neutral in a electrical panel. The young man asking the question stated that the neutral balances the load in a electrical panel, and some of our older electrian's said no it doesn't. so the young man took a two 120volt light bulbs and hooked in series applied 240volt to them and said you now have a balanced load and you don't need a neutral wire. and asked so whats the neutral for. Please settle the argument.
In a perfect controlled environment where all is equal on both sides of the loads the neutral could be removed from the circuit and the loads would in fact be fine, they would now be in a series circuit. In the real world it would be few and far between where this would be the case so, the loads would not see equal voltage which would change current flow across them, one would be high and one would be low.


Try the same experiment using a 7 watt incandescent lamp and a 100 watt lamp.


Roger
 

roger

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Here's an illustration that may help.

3wire3.gif


Roger
 

kwired

Electron manager
Location
NE Nebraska
It is not so much "balancer" as it is a voltage "equalizer".

When loads are not "balanced" when in series with the 240 conductors it still ensures each side actually sees 120 volts instead of whatever differential you get because of differences in resistance of the loads.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
We had a question ask in our office today about the neutral in a electrical panel. The young man asking the question stated that the neutral balances the load in a electrical panel, and some of our older electrian's said no it doesn't. so the young man took a two 120volt light bulbs and hooked in series applied 240volt to them and said you now have a balanced load and you don't need a neutral wire. and asked so whats the neutral for. Please settle the argument.

Is this a real argument about how current flows on the neutral? Or merely a semantic argument about how to describe it?

I'd say the red part is incorrect and the blue part is correct (in a way). So if the older electricians says all of it is wrong then it's hard to settle this argument since both sides are half right. :D

I think what Golddigger said states it pretty well with respect to current.
 

JFletcher

Senior Member
Location
Williamsburg, VA
Ask the young man what would happen if he lifted the neutral from the bus bar in a panel in a MWBC and the loads werent balanced. More to the point, if he could afford to replace whatever he fries.

240V loads like AC, ranges, dryers, water heaters are balanced and few require neutrals. The only way to balance 120V loads so that the neutral isnt needed would be to have equal amperage draw on both legs of a 240V system, or across all three phases in a 208V system.

The loads are what are balanced, not the neutral. The neutral provides balanced voltage when the loads are unbalanced.
 

Strathead

Senior Member
Location
Ocala, Florida, USA
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Electrician/Estimator/Project Manager/Superintendent
We had a question ask in our office today about the neutral in a electrical panel. The young man asking the question stated that the neutral balances the load in a electrical panel, and some of our older electrian's said no it doesn't. so the young man took a two 120volt light bulbs and hooked in series applied 240volt to them and said you now have a balanced load and you don't need a neutral wire. and asked so whats the neutral for. Please settle the argument.

I feel that this is a case of misdirection. Others have stated what the neutral does, and "carries the unbalanced current" is probably the best way to put it, as oppose to "balances the load". But the question is wrong. The bigger question is why the neutral? First, I believe it is there to reduce the voltage to ground as in for safety purposes. Second it is for economy, or was until the code people made it more difficult by requiring handle ties on multi-wire branch circuits, by reducing the number of wires needed in a system. On a Navy submarine, for example, there is no neutral. 120 volts for land based things like iphones and electric razors is delivered by three phase 120 volts delta.
 

kwired

Electron manager
Location
NE Nebraska
I feel that this is a case of misdirection. Others have stated what the neutral does, and "carries the unbalanced current" is probably the best way to put it, as oppose to "balances the load". But the question is wrong. The bigger question is why the neutral? First, I believe it is there to reduce the voltage to ground as in for safety purposes. Second it is for economy, or was until the code people made it more difficult by requiring handle ties on multi-wire branch circuits, by reducing the number of wires needed in a system. On a Navy submarine, for example, there is no neutral. 120 volts for land based things like iphones and electric razors is delivered by three phase 120 volts delta.
Sorry dude but it has nothing to do with reducing voltage to ground. You can ground any conductor of the system you want, we just happen to ground the neutral to keep voltage to ground as low as practical, but could certainly ground any other conductor if we really wanted to and the system would still operate the same - just with a different reference to ground.

Grounding and bonding to whichever conductor we choose to be grounded does help with limiting voltage to ground.
 

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
Sorry dude but it has nothing to do with reducing voltage to ground. You can ground any conductor of the system you want, we just happen to ground the neutral to keep voltage to ground as low as practical, but could certainly ground any other conductor if we really wanted to and the system would still operate the same - just with a different reference to ground.

Grounding and bonding to whichever conductor we choose to be grounded does help with limiting voltage to ground.

I didn't mean first and foremost I meant first as in a list. We choose this conductor to limit voltage to ground. I don't really see a distinction between what you wrote and what I did, other than you started with "Sorry dude."
 

kwired

Electron manager
Location
NE Nebraska
I didn't mean first and foremost I meant first as in a list. We choose this conductor to limit voltage to ground. I don't really see a distinction between what you wrote and what I did, other than you started with "Sorry dude."

We choose neutral on systems that have a neutral because it is a lower potential from neutral to other conductors of the system, otherwise you can ground any point of the system and have a ground reference, which does limit voltage to ground.

If you have an ungrounded system you can sometimes measure some pretty high capacitively coupled voltages, but with a grounded system that will typically become limited to the voltage between grounded and ungrounded conductors.
 
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