220vac 1p to 110vac 1p

[briarpatchbluehen]

I have a 30 amp 220vac service receptacle (wired for a dryer but never used). I have a special need for a 30 amp, 110vac connection and would like to tie into this receptacle somehow.
There are three wires connected to this receptacle: Black, Red and Green (all insulated).
I checked voltages across wires and I get 220vac between the black and red, and 110 vac between black and green and red and green.
Can I use either the black and green or red and green (with no ground wire) to get 110vac safely?

 

[waross]

In Canada this would be a 240 volt receptacle and it would ot be allowed to use the ground connection for a neutral.
I understand that at one time, the NEC allowed a shared conductor for ground and neutral for driers and electric ranges.
However this gives rise to three issues;
The ground conductor is often smaller than the load conductors. For a 120 volt circuit the neutral must be the same size as the load conductors.
This code relaxation may apply only to driers and ranges and not to utility receptacles.
I believe that the code may have been changedg so that this practice is no longer allowed.
Using a ground for a neutral or a neutral for a ground is a code violation and a safety issue.
Taping the black or red wire with white tape at both ends, reconnecting it to the neutral bus and using it as the neutral is a violation of the rule that requires a neutral to be permanently identified for its entire length. Not a serious safety issue.
The proper way to do this is to either add a white conductor in the conduit or change the cable for one that has one white colored conductor in addition to the bare or green grounding conductor.
Alternately you may add a 240:120 volt transformer.
I won't suggest an installation contrary to code, but:
Many professionals would hesitate before taping a conductor white on a job that would be subject to inspection, but do it in their own homes.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[VEBill]

Bad idea. Green is ground. Although ground is connected to neutral at your panel, but it is a very bad idea to use the ground wire as a neutral.

 

[itsmoked]

What is your "special need"?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[briarpatchbluehen]

My "special need" is to provide power to a mini ROV that requires to be plugged into a 110vac, 1P, 30 amp receptacle (similar to an RV). I have a 220 amp, 1p 30 receptacle and was hoping to use that but I have an issue with the wires (which ones to use? if at all).

 

[itsmoked]

I would consider taping the red wire wire white for as far as it can be seen on both ends. Doubtless it is not visible or even accessible anywhere else along its length. Then changing it's position to the neutral bar in the service panel. Resocket the garage outlet for 1P, 30A.

You also need to make sure the breaker running the remaining black wire is correctly rated for your new socket.

If you don't completely understand this entire discussion find someone who does, to help you, as working on live service panels is not a completely safe endeavor.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[rbulsara]

brianpathbluehen:

Get an electrician and pay him to do the right thing. A Lot cheaper than risking your limb or life.

 

[etarhan]

Sorry for butting in, but although I have no idea about the wiring codes and practices in the North America, the idea of a 110VAC ground connection seemed a bit absurd to me. For me this means that, when the ground wire is somehow shorted to the metallic chassis of an appliance, the user will have *only* a 110VAC shock, no more.

Can the 110VAC available on the ground wire happen to be there due to the induced voltage on it, with the other end of the wire not connected to anything?

Regards,
Engin

 

[itsmoked]

The ground is the same potential as the neutral.

The neutral is the center tap of the 240VAC power drop to the home. The middle of a 240VAC winding is going to provide one half of the voltage of the full winding, when paired with either end of the full winding. Hence the 120VAC,(not 110VAC),when either of the HOT wires are compared to the ground.

For safety reasons you must not use the [green]ground[/green] wire for carrying any loads.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[etarhan]

Thanks itsmoked. I see where I goofed.

Good luck,
Engin

Good luck,
Engin

 

[jasonf987]

come now, simple answer...use a transformer! we all know the reason for the ground wire and it is def not there to carry your load.

 

[VTer]

Why not replace the 30amp 2 pole CB with a 30A 1P CB. Re-pull new wires (dryer wires are typically in conduit not romex) and put a new receptacle in? In any case the ground wire is prohibited to carry current under normal conditions.

"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla

 

[davidbeach]

dryer wires are typically in conduit not romex

Never seen a residential unit wired in romex use conduit for any branch circuit. Dryer circuits are often wired with UF cable rather than NM cable (romex), but cable none the less. rbulsara (Electrical)
6 Jan 09 18:55 hit the nail square on the head though.

 

[waross]

The main issue is the color of one wire. You have two load conductors and a ground conductor. The load conductors are red and black. The code says that for 120 volt circuits you must have a white colored neutral conductor. The code says you can't use white tape to mark the cable white. In this situation a lot of people break the code and tape one wire white on both ends and use it as the neutral.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[VTer]

waross,

Most dryers that I have seen are in unfinished basements where the recep is surface mounted to a box on CMU/concrete wall with conduit used, if I can remember correctly (at least my house uses conduit for the dryer in the basement)

"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla

 

[waross]

Interesting!

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[TheBlacksmith]

I agree that dryers in basements often use conduit; I used it myself when running wiring to an outlet in my garage on the back of the chimney for the fireplace in the adjoining den. However, since he is alking about powering a ROV/RV, perhaps his dryer outlet is in an attached garage )like mine, which has cable in the wall).