# Shared neutral on more than one circuit



## nap (Dec 4, 2007)

Richo said:


> Hello,
> 
> In my shop I will be putting in a 20 amp duplex receptacle where the 2 outlets are on separate 20 amp circuits. Can I share the neutral wire between these 2 circuits? The 12 gauge hot wire is rated for 20 amps but when you share the neutral for circuits totaling 40 amps, is a single 12 gauge wire OK?
> 
> ...


you need to hire an electrician so you don't kill somebody. The fact you asked:



> can I just use the same neutral/ground


means you have no idea what you are doing here. stop now and save a life. It might be yours you save.


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## Speedy Petey (Feb 1, 2004)

I have to agree with nap here. At least I must ask how you plan on _"wiring a 240V receptacle downstream of a 120V receptacle"_.


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## Richo (Dec 6, 2007)

Nap, I appreciate your concern but please don't insult my intelligence. I have been doing my own electrical wiring for over 10 years. The obvious answer is when in doubt, use a separate neutral wire for each circuit which is what I've always done in the past.



> At least I must ask how you plan on _"wiring a 240V receptacle downstream of a 120V receptacle"_.


I'm talking about on the same run of EMT conduit, each receptacle having their own wires run from the panel. I always thought that the neutral carried the same amperage as the hot but recently I opened up an outlet box that contained 2 circuits and they were sharing the same neutral wire. Apparently it was not wired by an electrician. 

I got my answer.


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## darren (Nov 25, 2005)

Now that you cleared up some questions, yes you can share one neutral between two hots as longs at the hots are on two different phases in the panel. Contrary to what most people think when hooked up to two different phases the neutral canels each other out, so if you have 18 on one hot and 15 on the other you will only have 3A on the neutral. If you hook the two hots up to the same phase you would have 33A on the neutral.

You can share the EMT with both plugs. Your 240V plug does not need a neutral and your emt can be used for your bond. So in your pipe you would have 3 hots(2 for the 240V, 1 for the 120V) and you will also have a neutral. This would give you 4 current carrying conductors and depending on where you are you may to have to derate your wires.


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## rjniles (Feb 5, 2007)

You should not be using 2 120 volt circuits to build a 240 volt circuit "down stream". Run separate conductors from a dedicated 2 pole breaker. And I agree with the others, if you would even consider doing when you planned, you need professional help.


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## Speedy Petey (Feb 1, 2004)

Richo said:


> I'm talking about on the same run of EMT conduit, each receptacle having their own wires run from the panel.


Then it is NOT downstream of a 120v receptacle. It is a different 240v circuit you are asking about, just using the same conduit. 
Also, a 240v circuit does not have/need/use a neutral. Are you talking about a 120/240v circuit? 





Richo said:


> I always thought that the neutral carried the same amperage as the hot but recently I opened up an outlet box that contained 2 circuits and they were sharing the same neutral wire. Apparently it was not wired by an electrician.


 NO, apparently it was wired by someone who knew what they were doing. The person currently looking at it apparently does not.
A shared neutral (multi-wire branch circuit) circuit is a perfectly safe, common and efficient way of wiring. 
The neutral of a properly installed MWBC carries only the *current imbalance*, NOT the combined current. 





Richo said:


> I got my answer.


Now you do.


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## nap (Dec 4, 2007)

> Richo;580480]Nap, I appreciate your concern but please don't insult my intelligence. I have been doing my own electrical wiring for over 10 years. The obvious answer is when in doubt, use a separate neutral wire for each circuit which is what I've always done in the past.


so, explain to me what a neutral wire has to do with a 240 volt circuit then? and then combining them as a "neutral/ground". 



> I'm talking about on the same run of EMT conduit, each receptacle having their own wires run from the panel. I always thought that the neutral carried the same amperage as the hot but recently I opened up an outlet box that contained 2 circuits and they were sharing the same neutral wire. Apparently it was not wired by an electrician.


again you show your ignorance. What you found was a multi-wire branch circuit and as long as the hot legs are on opposing legs or phases, it is quite legitimate. Real electricians put them in with regularity all across the country every day.
I have not insulted your intelligence as much as you have done that to me. I do this for a living and I know what is correct and what isn't here. Especially since you claim to have been doing this for over 10 years, you show an extreme lack of knowledge concerning the question at hand. I knew more than that as a 1st year apprentice.


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## Speedy Petey (Feb 1, 2004)

The statement "_I have been doing my own electrical wiring for over 10 years_" is pretty damn scary considering the obvious lack of knowledge and expertise that exists.


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## clashley (Nov 24, 2009)

Richo said:


> Hello,
> 
> In my shop I will be putting in a 20 amp duplex receptacle where the 2 outlets are on separate 20 amp circuits. Can I share the neutral wire between these 2 circuits? The 12 gauge hot wire is rated for 20 amps but when you share the neutral for circuits totaling 40 amps, is a single 12 gauge wire OK?
> 
> ...



You can share a neutral between two 120V circuits as multiwire branch circuit (MWBC), with some caveats:


The neutral connection should pigtailed to all receptacles/devices, not passed through. If the neutral connection fails at any point, the two hot legs will essentially try to become a single 240V circuit.

The hot legs of the MWBC must be installed on opposite hot legs of your panel, and must be protected in such a manner that both legs will trip simultaneously in event of overload. You need to use either a 20A/15A (depending on the gauge of your circuit wiring) double-pole breaker, or two paired single-pole breakers connected with a common trip handle.

*Both of these requirements must be met!* Make sure your neutral connections are securely pigtailed at every junction and that your breaker is a either a double-pole or paired single poles with a common trip handle.

I would run a separate circuit for the 240V receptacle. This would allow you to use whatever size breaker (with appropriate wiring) necessary for your 240V application, since the MWBC will be limited to 20A.

I do have a couple of concerns about your proposed set up, though:

You mentioned that you were splitting a receptacle between two circuits. If you are using 20A breakers, you MUST use a 20A receptacle, not a 15A. You cannot place a single 15A receptacle on a 20A circuit (if it is a duplex receptacle, that counts as two receptacles on a single circuit and a 15A duplex receptacle is permitted on a 20A circuit).

The other question is how are you providing GFCI protection to this circuit? You will not be able to split a GFCI duplex receptacle into two circuits, although you could easily gang two GFCI receptacles into a single box and put them on separate legs of a MWBC with a shared, pigtailed neutral.


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## Richo (Dec 6, 2007)

Please disregard the word "downstream" as I didn't realize it had a special meaning with wiring, and all I meant by that was _further down the conduit_, but on its own breaker.


> You should not be using 2 120 volt circuits to build a 240 volt circuit "down stream". Run separate conductors from a dedicated 2 pole breaker. And I agree with the others, if you would even consider doing when you planned, you need professional help.


Apparently you misunderstood my question if you thought I was considering something foolish like that. Apparently my wording was not clear as to what my question was. As I reread my first post (2nd question) about the 120/240, I was meaning the ground wire, not the neutral. There are currently 2 floor boxes of PVC conduit which have 120V receptacles in each. I need to put a NEMA 6-15 into one of them. I know I have to run 2 hots from a 2 pole breaker but I simply wanted to know if they can share the same ground wire that is already there or if I have to run a separate one for the 240V circuit. I used the term neutral/ground because they are tied together in the panel.


> yes you can share one neutral between two hots as longs at the hots are on two different phases in the panel.


That was all I wanted to know from my first question. Thanks.


> The statement "_I have been doing my own electrical wiring for over 10 years_" is pretty damn scary considering the obvious lack of knowledge and expertise that exists.


Electricians are formally trained. For 20 years I've read books and watched DIY shows. Just because someone didn't go through the training to become licensed doesn't mean that they don't know the proper measures to do something as simple as run conduit or romex and pop a breaker in a panel, install lights and switches, etc. Anything more than that is undeniably beyond the scope of my knowledge and I would not attempt to do it without proper research.

Thanks for the info.


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## Richo (Dec 6, 2007)

> You can share a neutral between two 120V circuits as multiwire branch circuit (MWBC), with some caveats:
> 
> 
> The neutral connection should pigtailed to all receptacles/devices, not passed through. If the neutral connection fails at any point, the two hot legs will essentially try to become a single 240V circuit.
> ...


Very well explained...and yes, I do have 20A receptacles. That helps alot :thumbsup:


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## nap (Dec 4, 2007)

clashley said:


> You mentioned that you were splitting a receptacle between two circuits. If you are using 20A breakers, you MUST use a 20A receptacle, not a 15A. You cannot place a single 15A receptacle on a 20A circuit (if it is a duplex receptacle, that counts as two receptacles on a single circuit and a 15A duplex receptacle is permitted on a 20A circuit).


the circuits must be on a common trip breaker as well (if it hasn't already been addressed)


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## AllanJ (Nov 24, 2007)

Nitpicking. You can use 15 amp receptacles including singles on a 20 amp circuit so long as there are at least two receptacles altogether.

For multiple circuits in a conduit, run one ground wire sized for the largest amperage circuit present. For example for one 30 amp circuit and two 20 amp circuits, run one 10 gauge ground wire.

While a 120/240 volt circuit i.e. a common multiwire branch circuit can serve both 120 volt and 240 volt receptacles, most 240 volt appliances use enough amperes that you would not want to share a 20 amp circuit.

While 30 amp 120 volt receptacles exist for use on circuits of that capacity, you may not connect a fixture not rated for a 30 amp circuit and you may not modify a light or appliance to have a 30 amp plug for use on that circuit.


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## Hourglass52 (Dec 27, 2010)

*Shared Neutral*

If you insist on using a shared neutral.

There are several points to be aware of when dealing with multiwire circuits. 
The first is that the two HOT wires must be connected to opposite legs of your service in the panel. This ensures that the current in that "shared neutral" wire is the difference and not the sum of the currents in the two HOT wires. 
To confirm this, you should be able to measure 240V between the red and black HOT wires while seeing the typical 120V between either HOT and the white Neutral wire.


Installing multiwire branch circuits needs to be done in compliance with 210.4 of the 2002 NEC. 
The important issue here is ensuring the ungrounded conductors end up on different phases. If not, the neutral currents will not cancel out and will overload the neutral conductor. 
However, placing the ungrounded conductors on the different phases also has its problems. If the neutral were to open during operation, you essentialy have placed the two circuits in series with each other. This in effect cause low and high voltages outside of nominal ranges that can damage equipment. 
Great care must be taken when installing multiwire branch circuits.

Is all of this worth saving $10 on wire?


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## Speedy Petey (Feb 1, 2004)

Hourglass52 said:


> Is all of this worth saving $10 on wire?


I'll repeat as I have done on many forums. Using MWBC's is NOT always or only about money. That is a knee jerk reaction comment from those that don't know any better.
There are several benefits to MWBC's, of which money is not the most important one. 

TO say you should not use them because the neutral might open is like saying you should not have a service to your house because the neutral might open. That's right, the service to your house is one big MWBC. 

WIRED PROPERLY they are perfectly safe and efficient. If you don't know what you are doing then stay away from them, or any wiring.


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## brric (Mar 5, 2010)

speedy petey said:


> i'll repeat as i have done on many forums. Using mwbc's is not always or only about money. That is a knee jerk reaction comment from those that don't know any better.
> There are several benefits to mwbc's, of which money is not the most important one.
> 
> To say you should not use them because the neutral might open is like saying you should not have a service to your house because the neutral might open. That's right, the service to your house is one big mwbc.
> ...


 amen.


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## Hourglass52 (Dec 27, 2010)

Whatever


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## AllanJ (Nov 24, 2007)

It is not unusual to run a MWBC to several outlet boxes expecting to alternate A side and B side for the receptacles. But if you need GFCI protection you would need either a GFCI breaker (240 volt double wide) or individual GFCI receptacles at every outlet box where you do not use any load side terminals.

If you connected a GFCI receptacle to a MWBC, the load terminals are not part of the MWBC. A separate "GFCI protected neutral" must accompany the GFCI protected hot wire to any additional parts of the circuit to be protected by that GFCI.

Conduit fill and temperature derating requirements may in some cases allow a MWBC with more amperes compared with circuits with separate hot and neutral.


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## lfparker (Jan 30, 2011)

Hello - I need two dedicated 20 amp 120 volt outlets in my basement shop. One is for a compressor and one is for an air cleaner. I would like to do it with a MWBC using 12-3 romex from the panel to my shop. I understand that I will be good as long as I use a 2-pole breaker back at the panel. Since this is an a work area in my basement, it will need to be GFCI protected. If I terminate each circuit with a single GFCI outlet, will I be good? Thanks.


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## darren (Nov 25, 2005)

Yes you can feed two GFI on a multiwire branch circuit. You HAVE to make a joint on the neutral for this to work. On that note you always have to make a joint on the neutral when you are dividing the circuits on a MWBC.

You can not use a 3 wire to come off the line sides of two GFI and share the neutral.


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## lfparker (Jan 30, 2011)

Thanks - I understand the theory, but as a practical matter, is my proposed wiring sequence correct?

After running 12-3 romex from a 2-pole 20 amp breaker at the panel, at circuit 1 GFCI receptacle I should:

connect the black hot wire to the receptacle screw.
pigtail the white neutral and feed to the 2nd circuit's GFCI receptacle.
pigtail the ground and feed it also to the 2nd circuit's GFCI receptacle
splice the red wire with a wirenut to the black wire on another section of 12-2 romex and feed to the 2nd circuit.
Then at the second circuit I terminate the black, white, and ground on the GFCI receptacle.

I think this is correct, is that right or am I offbase? Thanks.


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## jbfan (Jul 1, 2004)

lfparker said:


> Thanks - I understand the theory, but as a practical matter, is my proposed wiring sequence correct?
> 
> After running 12-3 romex from a 2-pole 20 amp breaker at the panel, at circuit 1 GFCI receptacle I should:
> 
> ...


Right on the money!


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## lfparker (Jan 30, 2011)

Cool thanks!


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## AllanJ (Nov 24, 2007)

darren said:


> You can not use a 3 wire to come off the line sides of two GFI and share the neutral.


You mean load side, no?

Probably not common but you could have a MWBC feed arrive at a square or double gang box where there are two GFCI duplex receptacle units. Pigtail the neutral to the GFI line side neutrals, red wire to one GFCI line side hot and black to the other GFCI line side hot. Continue GFCI protection downstream using 2 wire cable(s) from the load terminals of one or both GFCIs.


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## darren (Nov 25, 2005)

Allan that is what I meant, thanks for correcting that.


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## skipoff (Apr 20, 2013)

wow guys ...you might know alot about eletrical but your communications skills need work. I understood what he was talking about in the very first thread. You made it very complicating...he said nothing about 240 volt. Reread his first post and quit being so arragant. He wants to create two outlets on two seperate breakers and he wants to know if he can share the neuteral (white wire....sorry for being a smart ass). This site is to HELP with DIY not make them feel stupid.


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## skipoff (Apr 20, 2013)

oops disreagard thte 240 comment....didnt see his second paragraph.


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## skipoff (Apr 20, 2013)

Ok, lets see if i can gets a POLITE answer about my question. I am creating a mother inlaw. 50 ft run in 1" plastic conduit. stove and microwave. stove on 50 amp breaker microwave on 20 amp breaker. stove hase 4-8 gauge wires 2 hot/1 neuteral/1ground. microwave using 12 gauge. Question is....can I use the 8 gauge neuteral and ground form the stove to share with the microwave? Now that is as plain and simple of a question as i can possible make it. Thanks and please dont be rude....


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## stickboy1375 (Apr 28, 2012)

skipoff said:


> Ok, lets see if i can gets a POLITE answer about my question. I am creating a mother inlaw. 50 ft run in 1" plastic conduit. stove and microwave. stove on 50 amp breaker microwave on 20 amp breaker. stove hase 4-8 gauge wires 2 hot/1 neuteral/1ground. microwave using 12 gauge. Question is....can I use the 8 gauge neuteral and ground form the stove to share with the microwave? Now that is as plain and simple of a question as i can possible make it. Thanks and please dont be rude....


Try starting a new thread...... hope that wasn't rude.


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## stickboy1375 (Apr 28, 2012)

skipoff said:


> I am creating a mother inlaw.


I dont recommend this.... nothing good will come of it. :jester:


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## RWolff (Jan 27, 2013)

I've run a lot of conduit over the years, but I've never shared neutrals or just let the conduit act as a ground wire substitute, I've always run separate wires for each circuit and breaker, as well as a green ground wire positively connected to each box with a screw. I never trusted the relatively flimsy connections between the emt pipes, couplers and boxes to be 100% perfect 100% of the time, thus I always used a green wire screwed to each box and connected to the green wire of any fixture there.


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## stickboy1375 (Apr 28, 2012)

RWolff said:


> I've run a lot of conduit over the years, but I've never shared neutrals or just let the conduit act as a ground wire substitute, I've always run separate wires for each circuit and breaker, as well as a green ground wire positively connected to each box with a screw. I never trusted the relatively flimsy connections between the emt pipes, couplers and boxes to be 100% perfect 100% of the time, thus I always used a green wire screwed to each box and connected to the green wire of any fixture there.


He's using plastic conduit... just saying.


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## stickboy1375 (Apr 28, 2012)

RWolff said:


> I never trusted the relatively flimsy connections between the emt pipes, couplers and boxes to be 100% perfect 100% of the time, thus I always used a green wire screwed to each box and connected to the green wire of any fixture there.


Funny, because I never really trusted someone to install a green wire to a screw to be 100% perfect, 100% of the time...


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## k_buz (Mar 22, 2012)

There are studies that say using EMT as the fault path is a better alternative to pulling an EGC. I'll be dammed if I can find them tho.


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## Speedy Petey (Feb 1, 2004)

skipoff said:


> wow guys ...you might know alot about eletrical but your communications skills need work. I understood what he was talking about in the very first thread. You made it very complicating...he said nothing about 240 volt. Reread his first post and quit being so arragant. He wants to create two outlets on two seperate breakers and he wants to know if he can share the neuteral (white wire....sorry for being a smart ass). This site is to HELP with DIY not make them feel stupid.





skipoff said:


> Ok, lets see if i can gets a POLITE answer about my question.


Welcome to the forum. I'm sure you'll do quite well with an opening like this. :laughing: :laughing:

And I agree. You should have started a new thread.


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## stickboy1375 (Apr 28, 2012)

k_buz said:


> There are studies that say using EMT as the fault path is a better alternative to pulling an EGC. I'll be dammed if I can find them tho.


Georgia Institute of Technology did these tests I believe.


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## rjniles (Feb 5, 2007)

skipoff said:


> Ok, lets see if i can gets a POLITE answer about my question. I am creating a mother inlaw. 50 ft run in 1" plastic conduit. stove and microwave. stove on 50 amp breaker microwave on 20 amp breaker. stove hase 4-8 gauge wires 2 hot/1 neuteral/1ground. microwave using 12 gauge. Question is....can I use the 8 gauge neuteral and ground form the stove to share with the microwave? Now that is as plain and simple of a question as i can possible make it. Thanks and please dont be rude....


You take an old thread and tell everyone they were rude and then ask for help on your project. Now that's not only rude but stupid. And you can't fix stupid.

Wire it with lamp cord, it will be fine.


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## RWolff (Jan 27, 2013)

stickboy1375 said:


> Funny, because I never really trusted someone to install a green wire to a screw to be 100% perfect, 100% of the time...


That's why you do things yourself so you know how they are done, when you rely on a 2nd party to do your work for you they cut corners, sluff off or get lazy.
This can be said of wire nutting too, they can come loose, corrosion/oxidation can happen.

With the separate green grounding wire, the metal conduit still acts in the capacity of a redundent ground were something to go wrong, or some fool forgets to connect the breaker box end of that wire and it's just left danging in the box.

You can still get a small water leak over a box that causes the grounding screw to begin corroding, just as latex paint slopped over the conduit and boxes can get a little corrosion started right where the coupler screws clamp down on the metal conduit, but having both is not a negative.


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## RWolff (Jan 27, 2013)

k_buz said:


> There are studies that say using EMT as the fault path is a better alternative to pulling an EGC. I'll be dammed if I can find them tho.


Well if you find them be sure to post a link, but I'll say this much, having the green ground wire in metal conduit *is an additional* safety, not the sole one as the conduit alone would be. The conduit's reliance on each coupler screw being tight, making a good contact, and actually clamped down on the tube. If any coupler screw happens to come loose over time, vibration, corrosion form latex paint damages it etc then the whole run of conduit could become hot if there was a fault.
That's one reason why I like the additional green wire inside, attached to every box, fixture and appliance.
The cost to add the green wire is for just one wire, it takes as much time/work to pull 3 wires through 50' of conduit as it does 2 wires.

I would never use plastic conduit...


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## stickboy1375 (Apr 28, 2012)

RWolff said:


> Well if you find them be sure to post a link, but I'll say this much, having the green ground wire in metal conduit *is an additional* safety, not the sole one as the conduit alone would be. The conduit's reliance on each coupler screw being tight, making a good contact, and actually clamped down on the tube.
> *The cost to add the green wire is for just one wire.*
> 
> I would never use plastic conduit...


If you were bidding a 2000amp feeder, I highly doubt you would pay for EGC within the metal raceway with your own money.


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## RWolff (Jan 27, 2013)

k_buz said:


> There are studies that say using EMT as the fault path is a better alternative to pulling an EGC. I'll be dammed if I can find them tho.



You might mean this one:

http://www.steelconduit.org/pdf/groundingpart1.PDF



> For a phase to conduit fault, the fault current will return to the source through the conduit and facility ground. It is possible that for a phase to conduit fault the
> only return path for the fault current is the conduit. This is possible for the systems illustrated
> in Figures 2.1a, 2.1c, and 2.1d. For a single phase to neutral conductor fault, the fault current
> return path is through the neutral conductor; the neutral conductor may have a higher
> ...


As you said, this agrees with the conduit acting as the fault grounding and a separate conductor is not *necessary*:


> Where l engths do not exceed the maximum allowable computed by the method,
> supplemental grounding conductors in secondary power systems enclosed in steel
> EMT, IMC or RIGID conduit are not necessary.




However, the additonal green wire IS required by the NEC under certain installations per this:



> The supplemental conductor is sometimes required by the NEC in critical installations such as health care areas, where dual protection for patients is considered prudent.


All of which when boiled down essentially says the conduit is acceptable just as you said, but adding the green wire simply exceeds the requirements for normal installations, and in certain circumstances it is required.
Obviously for accent lights in an art gallery it's hardly critical patient care in a hospital type of situation and the green wire is not necessary or required, but it's there and I feel better about it being there and that's what counts


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## jproffer (Mar 12, 2005)

Ok, this is 2 years old, but at least I'm not the first to comment since then  

so I'll bite.....

why would you not use PVC conduit?


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## stickboy1375 (Apr 28, 2012)

jproffer said:


> Ok, this is 2 years old, but at least I'm not the first to comment since then
> 
> so I'll bite.....
> 
> why would you not use PVC conduit?


many reasons, PVC simply not allowed, other conduit spec'd out on the prints, etc..


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## jproffer (Mar 12, 2005)

He made it sound like a personal choice. 

If it's against code, then so-be-it...if it's spec'ed out as EMT, then ok. Just thought maybe he had reasons other than "forced" reasons.


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## stickboy1375 (Apr 28, 2012)

jproffer said:


> He made it sound like a personal choice.
> 
> If it's against code, then so-be-it...if it's spec'ed out as EMT, then ok. Just thought maybe he had reasons other than "forced" reasons.


Oh, i have no idea, sounds like he's just a commercial guru, they get tunnel vision on other wiring methods outside of the commercial atmosphere...


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## JasperST (Sep 7, 2012)

jproffer said:


> why would you not use PVC conduit?


Metal is better in case someone slops some paint on a ground screw. I guess.


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## stickboy1375 (Apr 28, 2012)

JasperST said:


> Metal is better in case someone slops some paint on a ground screw. I guess.


??? why would that change anything?


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## jproffer (Mar 12, 2005)

And there's nothing particularly wrong with that :thumbsup:

I was just curious.


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## stickboy1375 (Apr 28, 2012)

jproffer said:


> And there's nothing particularly wrong with that :thumbsup:
> 
> I was just curious.


i know, but when someone is fixated on how they do things, they bring to much opinion into what is required, sometimes it can cost someone money they didnt need to spend on doing a job.


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## jproffer (Mar 12, 2005)

JasperST said:


> Metal is better in case someone slops some paint on a ground screw. I guess.



:huh:

I don't get it. I'm not trying to be smart, I just don't know what you're getting at.


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## jproffer (Mar 12, 2005)

stickboy1375 said:


> i know, but when someone is fixated on how they do things, they bring to much opinion into what is required, sometimes it can cost someone money they didnt need to spend on doing a job.



Very true. I haven't compared prices on conduit in a long time, but if you're working for someone else, insisting on conduit that costs (let's say...throwing out a number) twice as much could cost you the job. (Not talking as an employee...but as a contractor working for a customer)


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## RWolff (Jan 27, 2013)

stickboy1375 said:


> If you were bidding a 2000amp feeder, I highly doubt you would pay for EGC within the metal raceway with your own money.


I was strictly talking about the normal 15, 20 or 25 amp lighting and outlet type circuits which use standard 10, 12 or 14 ga wire, not industrial applications!
Sorry if I wasn't clear on that but the thread was about the OP's normal non industrial wiring and that was what I had in mind.


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## stickboy1375 (Apr 28, 2012)

RWolff said:


> I was strictly talking about the normal 15, 20 or 25 amp lighting and outlet type circuits which use standard 10, 12 or 14 ga wire, not industrial applications!
> Sorry if I wasn't clear on that but the thread was about the OP's normal non industrial wiring and that was what I had in mind.


Just so you understand my point, i'm not against you in favor of pulling in an EGC, but if someone asks if it is required, you have to just say "no" and let the installer make the decision... saying its better to pull a EGC is just a false statement. Hope thats respectful enough.


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## RWolff (Jan 27, 2013)

jproffer said:


> Ok, this is 2 years old, but at least I'm not the first to comment since then
> 
> so I'll bite.....
> 
> why would you not use PVC conduit?


The better question is, why would you put matches next to a gasoline can? 

Plastic burns, it also gets brittle over time, it has no grounding ability either.
I don't trust plastic.


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## JasperST (Sep 7, 2012)

stickboy1375 said:


> ??? why would that change anything?


I was being sarcastic, based on "With the separate green grounding wire, the metal conduit still acts in the capacity of a redundent ground were something to go wrong, or some fool forgets to connect the breaker box end of that wire and it's just left danging in the box."

For the record, we used metal conduit in the military (never for a ground/backup though) for protection and explosion prevention.


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## RWolff (Jan 27, 2013)

stickboy1375 said:


> Just so you understand my point, i'm not against you in favor of pulling in an EGC, but if someone asks if it is required, you have to just say "no" and let the installer make the decision... saying its better to pull a EGC is just a false statement. Hope thats respectful enough.



Yeah, that's clear, and fair enough, for myself, my own opinion and circumstances, I prefer the added ground wire. I just prefer to do a little higher caliber of workmanship than the minimum required, or what just gets by, I always overbuild and overspec.
That is why for example, if a 2x4 stud is the minimum required size, I use 2x6 or even 2x8 if I feel it's right for the project.


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## RWolff (Jan 27, 2013)

JasperST said:


> Metal is better in case someone slops some paint on a ground screw. I guess.


Ok I see


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## RWolff (Jan 27, 2013)

JasperST said:


> I was being sarcastic, based on "With the separate green grounding wire, the metal conduit still acts in the capacity of a redundent ground were something to go wrong, or some fool forgets to connect the breaker box end of that wire and it's just left danging in the box."
> 
> For the record, we used metal conduit in the military (never for a ground/backup though) for protection and explosion prevention.



Heh, ok.
Yeah, the metal conduit in that application in the military would be for mechanical protection of the wires, same reason it's required in exposed areas like a basement, laundry room etc where romex if used could be damaged.


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## jproffer (Mar 12, 2005)

RWolff said:


> The better question is, why would you put matches next to a gasoline can?
> 
> Plastic burns, it also gets brittle over time, it has no grounding ability either.
> I don't trust plastic.


I still don't see the point. 

Matches next to a gasoline can is a silly comparison, so I won't even comment on that one.

Plastic burns...so what?...you're whole house will burn if it's lit up.

And as far as "no grounding ability", you pull a seperate ground anyway right :thumbsup: ...so what's the difference.


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## RWolff (Jan 27, 2013)

jproffer said:


> I still don't see the point.
> 
> 
> Plastic burns...so what?...you're whole house will burn if it's lit up.
> ...


You asked why not to use PVC, I stated my opinons and one fact (plastic burns, gets brittle) on why *I* would not use PVC conduit.



> Matches next to a gasoline can is a silly comparison, so I won't even comment on that one.


I would not put plastic around something that has the potential to get hot enough to set it on fire if something fails, that was why I used the analogy of gasoline and matches, sorry but that was the best analogy I could come up with in 3 seconds on the fly to make a point.


Right, I would always use a separate ground wire, but others DON'T with metal EMT, and if you use PVC you have to use a separate ground wire anyway, the cost of that one more wire etc probably cancels out any savings in cost of PVC v/s $1.49/10' 1/2" ($3.00/3/4" $5.49/1") EMT conduit.


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## jbfan (Jul 1, 2004)

stickboy1375 said:


> Georgia Institute of Technology did these tests I believe.


Go Jackets!!!:thumbsup:

Nothing more to add to this thread btw!


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## collegetry (Feb 7, 2012)

skipoff said:


> I am creating a mother inlaw. 50 ft run in 1" plastic conduit. stove and microwave. stove on 50 amp breaker microwave on 20 amp breaker. stove hase 4-8 gauge wires 2 hot/1 neuteral/1ground. microwave using 12 gauge. Question is....can I use the 8 gauge neuteral and ground form the stove to share with the microwave?


I was kind of curious about this scenario also. So can he use the 8 AWG neutral and ground from the 50A stove breaker for his 20A microwave circuit? Im assuming that the run from the panel is going to a junc box then splitting off.


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## k_buz (Mar 22, 2012)

No, you cannot do that.


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## collegetry (Feb 7, 2012)

Thanks. So in that case a separate #12 neutral would have to be pulled?


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## k_buz (Mar 22, 2012)

yep :yes:


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## skipoff (Apr 20, 2013)

rjniles said:


> You take an old thread and tell everyone they were rude and then ask for help on your project. Now that's not only rude but stupid. And you can't fix stupid.
> 
> Wire it with lamp cord, it will be fine.


 

Thanks


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## skipoff (Apr 20, 2013)

k_buz said:


> yep :yes:


 
And a thank you to you my friend for giving me a straight answer without the drama.


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## collegetry (Feb 7, 2012)

skipoff said:


> And a thank you to you my friend for giving me a straight answer without the drama.


I thought you had a good question just a bad way of asking it.


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## skipoff (Apr 20, 2013)

rosem637 said:


> I thought you had a good question just a bad way of asking it.


 
Just a bad attitude i guess when people call other people "stupid" I would love to chalange witts with them. I just thought it was a legit opening question for this post and the first comment was a little insulting. I am a contractor myself for many years and I still have alot to learn. There is a right and wrong way to do things, but, there are alot of right ways to do things, not just one. People have the right to there opinion just dont insult others in the process.


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## rjniles (Feb 5, 2007)

skipoff said:


> Just a bad attitude i guess when people call other people "stupid" I would love to chalange witts with them. I just thought it was a legit opening question for this post and the first comment was a little insulting. I am a contractor myself for many years and I still have alot to learn. There is a right and wrong way to do things, but, there are alot of right ways to do things, not just one. People have the right to there opinion just dont insult others in the process.



And you really think you did not insult everyone else with you first post?:whistling2: And before you challenge anyone, learn how to spell (or use a spell checker).


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## Speedy Petey (Feb 1, 2004)

skipoff said:


> Just a bad attitude i guess when people call other people "stupid" I would love to chalange witts with them. I just thought it was a legit opening question for this post and the first comment was a little insulting.


Are you looking at the same thread as I am???
The OP, while being highly experienced to the point that he has _"been doing my own electrical wiring for over 10 years"_ and _"For 20 years {has} read books and watched DIY shows"_, really had VERY little clue what he was doing, at least to the point of doing things correctly and safely.
NO ONE called him stupid. We just questioned his level of expertise and over-confidence.

YOU were the one to come on two years later and open this back up into a contentious thread. Things were fine until you did this.


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## Speedy Petey (Feb 1, 2004)

skipoff said:


> Ok, lets see if i can gets a POLITE answer about my question. I am creating a mother inlaw. 50 ft run in 1" plastic conduit. stove and microwave. stove on 50 amp breaker microwave on 20 amp breaker. stove hase 4-8 gauge wires 2 hot/1 neuteral/1ground. microwave using 12 gauge. Question is....can I use the 8 gauge neuteral and ground form the stove to share with the microwave? Now that is as plain and simple of a question as i can possible make it. Thanks and please dont be rude....


NO. You absolutely CANNOT do this. The neutral is already shared by the two hots of the stove.

How's that?


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## skipoff (Apr 20, 2013)

rjniles said:


> And you really think you did not insult everyone else with you first post?:whistling2: And before you challenge anyone, learn how to spell (or use a spell checker).


 
Thanks for correcting me. Always did suck at spelling.


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## skipoff (Apr 20, 2013)

Speedy Petey said:


> Are you looking at the same thread as I am???
> The OP, while being highly experienced to the point that he has _"been doing my own electrical wiring for over 10 years"_ and _"For 20 years {has} read books and watched DIY shows"_, really had VERY little clue what he was doing, at least to the point of doing things correctly and safely.
> NO ONE called him stupid. We just questioned his level of expertise and over-confidence.
> 
> YOU were the one to come on two years later and open this back up into a contentious thread. Things were fine until you did this.


 
Maybe not stupid but this is a "do it yourself" site. Not a "come to the site and have someone else tell you to NOT do it yourself". Just saying if I was the original poster i would have gotten frustrated about that comment.


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## skipoff (Apr 20, 2013)

...and sorry for reopening. I came here looking for answers and it was one of the first ones that google grabbed. Was not paying attention to the date. ...and I guess the first response might have rubbed me the wrong way.


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## Speedy Petey (Feb 1, 2004)

skipoff said:


> Maybe not stupid but this is a "do it yourself" site. Not a "come to the site and have someone else tell you to NOT do it yourself".


Regardless of the fact that this or any other is a DIY site, there ARE times when "_hire a pro_" IS the safe and proper answer.


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## RWolff (Jan 27, 2013)

skipoff said:


> ...and sorry for reopening. I came here looking for answers and it was one of the first ones that google grabbed. Was not paying attention to the dat


Personally I don't know what the big deal is about opening an "old" thread and why people seem to get all bent out of shape about it on forums, if the topic is relevant who cares what the date is!
Don't sweat the small stuff skip, you did no harm posting in a thread that had a relation to your issue, it's what happened afterwards that caused issues it looks like.


A few tips: don't go into a forum and immediately say something like you want *a polite* response, that remark makes an assumption or accusation that people on a forum are going to be rude, condescending or nasty to you, you already convicted the people without a trial and most people don't like that, it almost guarantees you will be addressed rudely no matter what forum you post that to.

If you were hiring an attorney and went to their office for advice, you wouldn't just walk in and sit down, and say something like "I want a POLITE response to my legal question and I want to know how much I gotta PAY you for this, and you'd better not overcharge me either!" chances are you would walk in, greet the attorney, shake their hand and introduce yourself and be invited to have a seat. It works pretty much the same on the internet.

Next, lurk and read and see what the forum is like, then just like walking into your neighbor's party- your first post is better being some kind of introduction/greeting to start off with, a "Hi, my name is____ and I just joined the forum, I live in _____state."


It's also a good idea to write out your question in a professional way, providing as many and complete details as you can, check the spelling and then re-read it before posting.

We all get sloppy with spell checking and all, I know I do, but remember- you get get one opportunity to make a first impression!


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## skipoff (Apr 20, 2013)

RWolff said:


> Personally I don't know what the big deal is about opening an "old" thread and why people seem to get all bent out of shape about it on forums, if the topic is relevant who cares what the date is!
> Don't sweat the small stuff skip, you did no harm posting in a thread that had a relation to your issue, it's what happened afterwards that caused issues it looks like.
> 
> 
> ...


I feel like I am 12 again.:huh:


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## Jim Port (Sep 21, 2007)

Some people do not know how little they know either. Electric work is not like plumbing where you can always see the problem regardless of your knowledge.


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## beenthere (Oct 11, 2008)

RWolff said:


> Personally I don't know what the big deal is about opening an "old" thread and why people seem to get all bent out of shape about it on forums, if the topic is relevant who cares what the date is!


Its not polite to hijack an old thread.

Many people don't like to read 2 or more pages of an old thread, and then find a new questions by someone else. Even if it is the same basic topic.


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## sirsparksalot (Oct 16, 2010)

Wow, 6 pages = 2 years.

Some forums encourage newbies to do a search for their problem before posting a question that may have been asked and answered a dozen + times. Then if we do that, and have a supplemental question, sometimes we get accused of hijacking, or opening an old thread. 

I rarely search for an answer before posting because there's so damn many to read through just to find that I may have an independent situation. Plus, I'm lazy, and find it quicker to just ask my own question, even if I think it has been answered before.

But anyhow, if you come to Electrical forums be prepared to grow some, cause there's very little tolerance among electricians for DIYers who ask very basic questions; as it should be, because this is dangerous territory.

I've been there, still am, and so must you, too.


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## oh'mike (Sep 18, 2009)

You electricians show a great deal of patience with the members---some times you bawl them out first but you all help a willing and intelligent member learn the basics----


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