110V off 220V circuit

[aczlan]

So I am not trying to be argumentative, but what no one has answered is why. I know there is a good reason but I have yet to understand it.

The simplest answer is "Because that is what the code requires"

In the box white and copper. (neutral and ground) are tied to the same spot. Yes there are two different terminal strips but the both are attached to the wire leading to the grounding rod.
So if there is a fault with an incorrect 2 wire 110 hookup(meaning neutral and ground on the same wire) what is the danger. If hot where to contact neutral the current would still ind up at the ground in the box.

See: Why do we need to bond neutral & ground in breaker box
From there:

The "neutral" is technically called the "grounded" conductor. It is grounded by ground rods at the utility transformer by the utility. We must ground it also at the service entrance, which can be at either or both the meter and main switch, technically called the Service Disconnecting Means.

Most panels, such as you refer to as the Main Breaker Box, has the main switch in it. It is at this point the neutral is grounded by connecting to a grounding electrode.

Sidebar to confuse you, if the main switch is ahead of the panel, such as outside at the meter, the grounding and bonding of the neutral is done at the main switch, not at the panel.

It is from this point the neutral must be separate from any other grounding, and must be separate from the equipment grounding conductor (bare or green wire) in any branch circuit. Since the neutral is the return for any 120 volt circuit, it is a current carrying conductor. The bare or green wire of each branch circuit is reserved to only carry current back from a circuit if there is a ground fault (short circuit).

The equipment grounding conductor is intended to be reserved to be ready to carry any fault current back from a short circuit, in an effort to allow the current to rise quickly to trip the circuit breaker for the circuit with the problem.

This acts as a safety/redendant return for a circuit. Connection of the neutral/ground at the main switch insures that all neutrals and grounds are now at the same earth potential, and the equipment ground is created, or begins.

Since a "subpanel" is downstream from the main switch, it is considered as a branch circuit, and is treated the same as a branch circuit, separate and insulated neutral return for any 120 volt circuits, and a separate equipment ground for any metal, such as the panelbox.

A neutral can be touched with no fear of injury, as it is at zero earth potential, because it has been grounded.

Aaron Z

 

[dieselscout80]

A couple of things:

Some of the questions in this thread show zero understanding of household wiring and the safety practices that go into it. As such, you REALLY shouldn't be messing with it. You are about to make the most basic mistakes and potentially disable all the safety systems that you currently have.

The white (neutral) and bare (ground) coming together to the same terminal strip in your electric box is normal and correct, but note that the main breaker box is the ONLY place where the two are allowed to come together. You can't join them anywhere else in the house or outbuildings. As a side note, people installing generators almost always mess this up.

A 220V circuit is either split phase, or single phase. In a split phase circuit, there are 4 wires: Line 1 (black), line 2 (red), neutral (white), and ground (bare or green). From a split phase circuit you can extract 220V between L1 and L2, and you can extract 110V between L1 and N or between L2 and N. In a single phase circuit there are 3 wires: Line 1 (black), line 2 (white), and ground (bare or green). In a single phase circuit you cannot extract 110V because there is no neutral. Also, unlike a 110V circuit, the white wire is NOT neutral. It is HOT and can knock you on your butt or kill you, just like the black wire.

As to the original poster's question, nobody asked but it sounds like you have a single phase circuit. If that's the case, you cannot get 110V by rewiring the outlet. You can, however, rewire back at the electric box to make it a 110V circuit (changing the outlet appropriately as well). You would need a new single pole breaker (the 220V circuit will be on a 2 pole breaker). The white wire will become neutral and be wired to the terminal strip with most of the other white wires, and the black will go to the single terminal on the new breaker. You will also probably end up with an open slot in your breaker panel which needs to be plugged with an appropriate filler plate.

Someone else suggested using the ground as a neutral - after all, they are wired to the same terminal strip in the breaker box, right? I don't mean to be harsh, but this is the most basic mistake make by someone who knows nothing about household wiring. The ground wire should never under any normal operating condition be carrying current, which it will be doing if you use it as the neutral, or tie it to the neutral anywhere other than a single point at the main breaker panel (remember that rule from the first point). The only time the ground carries current is when there is a fault. It's there solely for protection.

Hope this helps, and stay safe. It's not just you, but also the unsuspecting guy who comes along after you expecting things to be wired properly only to find out the hard way that they are not.

I like your explanation which was my inital thought when I only saw a total of three wire (including the ground), but I wanted to ask so I knew the way it could be done correctly which is only on a 220Vac circuit with four total wires.

Thanks

 

[slowzuki]

Short answer, the neutral always carries current in a 120v circuit from the device back to the panel and the ground rod, the neutral usually carries current in a split circuit unless you lucked into a perfectly balanced load on the two side. The ground never carries current under normal conditions and is always grounded. Under normal conditions a neutral can electrocute you, a ground can not.

If you have a bad ground rod at the panel, the ground wire can become energized by neutral current. If you have a bad ground or no ground wire, faults in equipment can energize the grounded safety components of the equipment.

As an example, the previous owners of my sisters farm neglected to connect the ground wire in the barn wiring. A worker was climbing a hay conveyor to the loft when he got shocked an fell off breaking his arm. We checked the conveyer frame and with reference to the barn plumbing it had 90 volts ac. With reference to the ground wire it was 0. Following back through the barn someone had not connected a ground in a box. Damaged wiring in the motor on the conveyor was letting 120 v hot go to the motor frame, then to the conveyor frame, then up to the metal siding it was leaning on, then to ground. When the worker touched the siding, he became a better connection than the scraped paint and rust of the conveyor and was shocked. A working ground would have sent this current back on the ground wire to the panel. Today the outlet being outside would have had a GFCI and would have tripped as soon as the wire failed in the motor.

So I am not trying to be argumentative, but what no one has answered is why. I know there is a good reason but I have yet to understand it.

In the box white and copper. (neutral and ground) are tied to the same spot. Yes there are two different terminal strips but the both are attached to the wire leading to the grounding rod.

So if there is a fault with an incorrect 2 wire 110 hookup(meaning neutral and ground on the same wire) what is the danger. If hot where to contact neutral the current would still ind up at the ground in the box.

All the best

Carl

 

[ducks13]

Boy, there is a lot of misinformation here. Per 2008 NEC code:

200.6 Means of Identifying Grounded Conductors.
(A) Sizes 6 AWG or Smaller. An insulated grounded conductor of 6 AWG or smaller shall be identified by a continuous white or gray outer finish or by three continuous white stripes on other than green insulation along its entire length. Wires that have their outer covering finished to show a white or gray color but have colored tracer threads in the braid identifying the source of manufacture shall be considered as meeting the provisions of this section. Insulated grounded conductors shall also be permitted to be identified as follows:
(1) The grounded conductor of a mineral-insulated, metal-sheathed cable shall be identified at the time of installation by distinctive marking at its terminations.
(2) A single-conductor, sunlight-resistant, outdoor-rated cable used as a grounded conductor in photovoltaic power systems as permitted by 690.31 shall be identified at the time of installation by distinctive white marking at all terminations.
(3) Fixture wire shall comply with the requirements for grounded conductor identification as specified in 402.8.
(4) For aerial cable, the identification shall be as above, or by means of a ridge located on the exterior of the cable so as to identify it.

So basically the white wire is suppose to be the neutral or grounded conductor and it can稚 be remarked with tape to indicate it true purpose unless it is larger than #6 which I doubt is the case in your installation. A white conductor should never be connected to a breaker. You can take one of your current phase conductors (the red or black one) and connect it to the neutral bar and just leave the other wire attached to the breaker and you will have 110 at your outlet but you won稚 meet code and of course you will need to change the receptacle. There is no code issue to make you change the breaker to single pole. The ground wire is there so that the breaker will trip if a phase conductor touches something that it shouldn稚 that is grounded by the ground wire. Without it you could walk up to your air conditioner or whatever and touch the case and get shocked if the phase conductor is touching the metal and there is no ground connection.

 

[wedge40]

I've read through most of this thread and this is why I'm hiring out my electrical install for the barn. Once the panel is installed I can run additional circuits, but it's getting everything right between me and the electric company.

Wedge

 

[BobRip]

Shorter answer. With a separate ground and neutral a single failure of one or the other does not create a safety hazard. Always put two failures between you and death.

 

[slowzuki]

You can relabel a white neutral conductor into a current carrying conductor by colouring both ends. In fact you're required to. Its a code violation to go the other way turning another colour into the neutral BUT it is normal practise and accepted in most areas.

Boy, there is a lot of misinformation here. Per 2008 NEC code:

200.6 Means of Identifying Grounded Conductors.

 

[grsthegreat]

A couple of things:

Some of the questions in this thread show zero understanding of household wiring and the safety practices that go into it. As such, you REALLY shouldn't be messing with it. You are about to make the most basic mistakes and potentially disable all the safety systems that you currently have.

The white (neutral) and bare (ground) coming together to the same terminal strip in your electric box is normal and correct, but note that the main breaker box is the ONLY place where the two are allowed to come together. You can't join them anywhere else in the house or outbuildings. As a side note, people installing generators almost always mess this up.

A 220V circuit is either split phase, or single phase. In a split phase circuit, there are 4 wires: Line 1 (black), line 2 (red), neutral (white), and ground (bare or green). From a split phase circuit you can extract 220V between L1 and L2, and you can extract 110V between L1 and N or between L2 and N. In a single phase circuit there are 3 wires: Line 1 (black), line 2 (white), and ground (bare or green). In a single phase circuit you cannot extract 110V because there is no neutral. Also, unlike a 110V circuit, the white wire is NOT neutral. It is HOT and can knock you on your butt or kill you, just like the black wire.

As to the original poster's question, nobody asked but it sounds like you have a single phase circuit. If that's the case, you cannot get 110V by rewiring the outlet. You can, however, rewire back at the electric box to make it a 110V circuit (changing the outlet appropriately as well). You would need a new single pole breaker (the 220V circuit will be on a 2 pole breaker). The white wire will become neutral and be wired to the terminal strip with most of the other white wires, and the black will go to the single terminal on the new breaker. You will also probably end up with an open slot in your breaker panel which needs to be plugged with an appropriate filler plate.

Someone else suggested using the ground as a neutral - after all, they are wired to the same terminal strip in the breaker box, right? I don't mean to be harsh, but this is the most basic mistake make by someone who knows nothing about household wiring. The ground wire should never under any normal operating condition be carrying current, which it will be doing if you use it as the neutral, or tie it to the neutral anywhere other than a single point at the main breaker panel (remember that rule from the first point). The only time the ground carries current is when there is a fault. It's there solely for protection.

Hope this helps, and stay safe. It's not just you, but also the unsuspecting guy who comes along after you expecting things to be wired properly only to find out the hard way that they are not.

+1 agree 100%. IF the a/c is a home run (and you know its 100% sure that it is) you could rewire it to run 120 as mentioned here earlier. However it seems that you dont know much about house wiring and id hate you to get hurt. DONT use the ground as a neutral....DONT.

Just run an extention cord to do what you need to do from a true 110 outlet. Dont risk it. 220 KILLS fast

 

[hayden]

If there is no white wire he cannot do this!

Unfortunately you can't conclude anything just by the presence of a white wire. Both a single phase 220V circuit and a split phase 220V/110V circuit will likely have a white wire. Only in the split phase case is it a neutral. In a single phase circuit it will be hot.

It's correct practice in a single phase circuit to mark the end of the white wire with black tape or marker to indicate that it's hot, but don't count on it. It's probably safe to say that any building wired in the last 60 years is wired with romex or NM cable. Single phase 220V circuits are wired with 2 conductor + ground NM cable, and that cable consists of black, white, and bare, so the white gets used for one of the lines and is hot.

 

[grsthegreat]

Boy, there is a lot of misinformation here. Per 2008 NEC code:

200.6 Means of Identifying Grounded Conductors.
(A) Sizes 6 AWG or Smaller. An insulated grounded conductor of 6 AWG or smaller shall be identified by a continuous white or gray outer finish or by three continuous white stripes on other than green insulation along its entire length. Wires that have their outer covering finished to show a white or gray color but have colored tracer threads in the braid identifying the source of manufacture shall be considered as meeting the provisions of this section. Insulated grounded conductors shall also be permitted to be identified as follows:
(1) The grounded conductor of a mineral-insulated, metal-sheathed cable shall be identified at the time of installation by distinctive marking at its terminations.
(2) A single-conductor, sunlight-resistant, outdoor-rated cable used as a grounded conductor in photovoltaic power systems as permitted by 690.31 shall be identified at the time of installation by distinctive white marking at all terminations.
(3) Fixture wire shall comply with the requirements for grounded conductor identification as specified in 402.8.
(4) For aerial cable, the identification shall be as above, or by means of a ridge located on the exterior of the cable so as to identify it.

So basically the white wire is suppose to be the neutral or grounded conductor and it can稚 be remarked with tape to indicate it true purpose unless it is larger than #6 which I doubt is the case in your installation. A white conductor should never be connected to a breaker. You can take one of your current phase conductors (the red or black one) and connect it to the neutral bar and just leave the other wire attached to the breaker and you will have 110 at your outlet but you won稚 meet code and of course you will need to change the receptacle. There is no code issue to make you change the breaker to single pole. The ground wire is there so that the breaker will trip if a phase conductor touches something that it shouldn稚 that is grounded by the ground wire. Without it you could walk up to your air conditioner or whatever and touch the case and get shocked if the phase conductor is touching the metal and there is no ground connection.

Yes...and no. Again this is a rough call. Inspectors and the code allow you to paint or mark a #12 white wire to black in some instances...such as a switch leg where only a 14/2 is run to a switch. The white is hot after its labeled.