Where is that confounded neutral?

Jim Doolittle

Active Member
I just started with UPB and I knew that the box where I wanted to put some US2-40s didn't have a neutral but I thought that having a drop ceiling would not make it too difficult to bring a neutral to that box. However, the way the spotlights controlled by the box were wired they were daisy chain all over the place making it difficult to locate the neutral.

I have another set of fluorescents controlled by an X10 relay switch and had to pull a neutral for that a while back. Could I run that same neutral to the box for the US2-40s? If so, would it be "wrong" to simply run a one-wire BMX cable to the box for the US2-40s? Would that violate "typical" local codes?

Thanks

Jim
 

AO-Brandon

Active Member
romex is cheap, pull a new line and get it over with. even if you arent violating "typical" codes, you will probably be violating "local" fire codes.

it would work, no doubt, but i wouldnt want to risk it.
 

Event5

Active Member
All the neutrals in a panel go to the same place. All the same potential. Not associated with the breakers.
Dave
 

Guy Lavoie

Active Member
No...don't ever crosswire neutrals across two seperate circuits! Someone could get killed if they turn off a breaker to do wiring work on a circuit and the neutral is still returning current to ground for another unrelated (and still live) circuit.

Then there is the potential for one neutral conductor to be carrying the return current for two seperate breakers and the total current could exceed that wire's current carrying capability, causing a fire.

Neutrals should only meet at the panel, nowhere else!
 

Jim Doolittle

Active Member
Understood. I thought that the other light was on the same circuit. Realized it wasn't when I flipped the other light on/off.
 

noshali

Active Member
I am trying to do the same thing....

I got the basement finished and no neutral wire was put in (rest of the house has them). What is the best way to find out which light goes to which circuit? Also, for clarification, I am sure that the contractor tapped into existing junction boxes. What happens in that case. I have read the book on the neutrals but stuff like what you mention above is valuable information.

Also, there is a big bar for neutral (one on each side of tha panel. Does it matter where I screw the wire.

Thanks,
 

Guy Lavoie

Active Member
The best way to determine which light goes to which circuit is by simply turning off one breaker and then testing which lights have ceased to work. If the two sets of lights that you want to bridge the neutrals have both gone dead, then they are sharing the same circuit.

No, it does not matter which neutral bar you screw the wire to. In the panel, all neutrals meet. If this is the main service panel (first one after where the power first comes in) then this is also where the neutrals connect to ground. This is the only place where neutral and ground are to be bonded together.
 

Event5

Active Member
Guy,

I do not disagree with your concerns about care with the neutrals, however the statement that neutrals should only meet at the panel isn't the way it is. It is common practice that there are multiple neutrals that junction in almost every switch box with one neutral going back to the panel with a hot, connecting to the neutral buss. and all the other neutrals for each load tying into the one going back to the panel. It is the electricians responsibility to not overload a neutral in this configuration. In this configuration all the loads in this switch box are on the same circuit.
With that, when wiring "hot" there is the potential that a neutral is carrying current even though the load you are currently working on is not connected.

Dave
 

Guy Lavoie

Active Member
By "all neutrals should only meet at the panel", I'm referring to neutrals from different circuits. For any given circuit, yes it is normal for neutrals to branch off to various loads and switches.

The only exception to this is when there is a "shared neutral" that is used on a 120/240 volt circuit like those for kitchen outlets. In this case the two hots are known to be wired on different phases, so overloading of the neutral cannot occur. Ideally you should use mechanically linked breakers for such circuits, although electrical codes don't make it mandatory.
 

Sandpiper

Active Member
Event5....you are wrong. It is not common practice to share neutrals...and is against code.

Guy is absolutely correct. The "shared neutral" he mentions is what the NEC calls a multi-wire branch circuit....and he explained it correctly. The NEC describes it in section 210.4.

I suggest you obstain from giving advice on those things in which you are not familiar.
 

wuench

Senior Member
I agree don't share neutrals, or cross connect them. I don't care if code allows it or not. I have a house that is 5 years old and when I shut off the breaker to at least one switch that I know of, the neutral is still carrying current. I realize you may have knowledge of what goes where, but if you move, as someone said above, someone could get electrocuted.

People, including electricians, really should think about sh*t and not kludge it. I don't care if it saves some stupid cheap country bumpkin electrician a couple of bucks on wire. This shouldn't be allowed.
 

Event5

Active Member
I never said it was common practice to share neutrals. In my statement
It is common practice that there are multiple neutrals that junction in almost every switch box
I was attempting to describing the multi-wire branch circuit. Just doing a lousy job of describing. Guy does explain it much better. I also did not mean to imply it either. I was only attempting to describe what is correct and to code.(I repeat, just doing a lousy job of it)
I believe my statement:
All the neutrals in a panel go to the same place. All the same potential. Not associated with the breakers.
was describing what is found in a panel, and was not intended to imply anything else.
I apologize if my comments were not clear or implied not following code. I never intended that.
Thank you
 
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