Electricians: can neutral be anything but white?

[LD1]

If you can not afford a few runs of 3/4" conduit instead of 1/2" around a shop. It maybe time to re-think your finances .

No one said I couldnt afford it. Sure, the conduit is only a buck a stick more expensive. So thats only ~$30 than I spent now. But box connectors are also more expensive, you are pulling extra wire, and I already have a ton of single boxes with only 1/2" knockouts.

Its not all about saving money. Its about using surplus stuff I already have without buying new. And why spend extra money, and upsize stuff, if it wont make any difference in the end? Thats just wasteful.

Even still what advantage could this possibly gain?

I've been over this. Less wire = money saved. Smaller conduit = money saved. Pulling fewer wires = less work

I want to thank everyone for there responses. I have made my decision.

Those that are still against it, I encourage you to do a little more researching. From what I am gathering it is becoming more and more common to save money. There is no added danger, when done right it is not any less safe, and the circuit works just the same as one with twice as many neutrals. There is nothing wrong with a shared neutral, and after spending lots of time over the last few days researching, it seems the only guys that are against it, are the (hard headed-set in their ways-are always right) kind of electricians.

So far, no one has given me a legitimate reason for NOT sharing neutrals. All the outlets will function just the same. The whole" what about the next guy to work on it" is crap and I dont accept that as a good reason to pull 2 extra conductors through ~100' of conduit. Any competent electrician can open the panel, or work box and will know what is going on.

Again, thanks to all. You have answered the few questions I have had well enough for me to make my informed decision. If you want to continue arguing about circuit types, go for it.

 

[s219]

I get the impression that some folks are missing the point that the two hots are 180 deg apart in phase, so the neutral will never see more than the max amperage of one of the hots, and that would only occur if the other hot had no load at all. When both are loaded, the net amperage will vary somewhere between zero and max. It could never be more than the max amperage of one of the poles (certainly never double). The two phases will partially cancel each other out so that the net current is the difference in currents. If the currents were perfectly equal, the neutral would see no net current coming back.

The only criticism I can think of with a shared neutral would be possible oddball situations that can happen if the shared neutral is dropped. In a circuit with a dedicated neutral, you'd just lose power on that circuit (like flipping a switch). In the case of a shared neutral dropping, the shared circuits sort of lump into one big complicated 220V circuit, and the scenarios are endless.

 

[Fawken]

I get the impression that some folks are missing the point that the two hots are 180 deg apart in phase, so the neutral will never see more than the max amperage of one of the hots, and that would only occur if the other hot had no load at all. When both are loaded, the net amperage will vary somewhere between zero and max. It could never be more than the max amperage of one of the poles (certainly never double). The two phases will partially cancel each other out so that the net current is the difference in currents. If the currents were perfectly equal, the neutral would see no net current coming back.

The only criticism I can think of with a shared neutral would be possible oddball situations that can happen if the shared neutral is dropped. In a circuit with a dedicated neutral, you'd just lose power on that circuit (like flipping a switch). In the case of a shared neutral dropping, the shared circuits sort of lump into one big complicated 220V circuit, and the scenarios are endless.

I really am tired of this discussion, but what you're saying is that somehow if both circuits are using the same current there is no current returning to ground on the neutral. Sign me up! I could use some free electricity!

 

[ray66v]

So far, no one has given me a legitimate reason for NOT sharing neutrals.

I did give you one. You can't put arc fault breakers on a shared neutral.

It may not apply to your situation. But, it is a legitimate reason.

 

[buickanddeere]

When I changed out all of the outlets and switches in my house a few years ago and was talking about it at a neighborhood gathering, I was told by one of my neighborhood sparkies that is literally how the houses were wired in my city at the time: Put a load in the basement with a big electric motor and the lights sharing that neutral wire in the rest of the house flicker. As people have had sparky come in and add new outlets or change out electrical service boxes, the problem has been fixed, but many houses are still wired with a shared neutral with on, off and flicker. Thankfully everything is in greenfield and a couple of sparkies have told me they can fish more wire in and fix the issue if it comes up doing some service work.

Shared neutral ? Somebody was using the ground system to carry neutral current ?

 

[buickanddeere]

Nobody said there was anything wrong with Line 1 breaker and a Line 2 breaker supplied loads sharing the same neutral for mundane equipment or to a plain 20 amp T-Slot receptacle.

 

[s219]

I really am tired of this discussion, but what you're saying is that somehow if both circuits are using the same current there is no current returning to ground on the neutral. Sign me up! I could use some free electricity!

Each circuit's current is returning, but when they combine the two opposite phases cancel out, so that there is no net current load on the wire.

 

[Fawken]

Each circuit's current is returning, but when they combine the two opposite phases cancel out, so that there is no net current load on the wire.

I'll test it with an ammeter this weekend and post an actual picture of the read-out with two identical fans on the same speed setting, sharing a neutral on opposite poles of the center tap.

 

[SPIKER]

I really am tired of this discussion, but what you're saying is that somehow if both circuits are using the same current there is no current returning to ground on the neutral. Sign me up! I could use some free electricity!

Guess I should chime in: what the other guy (S219) said is correct. IF the loads on the 2 independent 120Volt lines (240volts between them) are equal and they are sharing a Neutral then the current coming thru the Neutral will be a net 0 current. THIS is why having GFI Breakers on a shared neutral is not going to work (the GFIC outlet) is looking at the current going OUT (hot) and that same current coming BACK thru the white/neutral wire. It will trip when the load imbalance (current out) goes back to the panel thru the other HOT lead bypassing the Neutral RETURN circuit.

To properly wire this (you CAN still do it) however the white wire and ALL the white wires from all down stream outlets must go back thru the GFIC's "White Wire" that are feed from that GFIC outlet. This way no unbalanced neutral loads are passed back thru the other hot leg It must go thru the white GFIC's wire terminal.
The single white wire and two hots and green can be on different (single pole) breakers mounted side by side like a 240 breaker so they are on opposite legs of the main panel. The run of 4 wires can be from main panel board to the middle at a 4x4 box with two GFIC breakers feeding different directions for a series of outlets as long as from that point (the GFICs) 5 wires are run keeping the white1 and white2 independent of each other just as the hots are kept independent.



------------hot1---------GFIC1----------OutletP1-(hot)-------------OutletP2 (hot)
---Neutral_shared---GFIC1(N)------OutletP1-(N)---------------OutletP2-(N)
`````````````````\
-----------Hot2----------GFIC2---------OutletP3-(hot)--------------OutletP4-(hot)
`````````````````GFIC2(N)-------OutletP3(N)-----------------OutletP4-(hot)

PE----------------------------0------------------0-----------------------------------0



Mark

 

[KennyG]

Each circuit's current is returning, but when they combine the two opposite phases cancel out, so that there is no net current load on the wire.

This is correct until you can envision alternating current as a push and pull. There will be a localized current on the neutral but the positive flow on one load returns as the negative flow on the other load rather than a current in the neutral. As we all know a 220v load will operate without a neutral so there obviously can be power transmitted without a neutral flow.