240 into two 120

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Old 08-03-06, 10:11 PM
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240 into two 120

Iím working in a big warehouse 50x100 that has 50 amp 3prong plugs at the two ends.
I want to make and extension cord 50 feet long that will run 3 120 volt 1/2 inch drills at the same time in the center of the building. How do I go from 240 volt at the plug to two 120 volt outlets at the other end?
This is how I was thinking of doing it. But I want to make sure its right.
Get a 3 prong plug that will fit the outlet, use 10-3 SOW wire, Hook up the red and black to each leg of the 240 volt and the white to the ground. At the other end (middle of the building) use a 4 gang metal box with two receptacles hook the red to the brass screw on one receptacle. The black to the brass screw on the other receptacle and the white pig tail to the silver screws on both receptacles and the ground.
What do you think?
 
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Old 08-03-06, 10:24 PM
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This is all wrong. Your 240 receptacles have 2 "hot" leads but NO Neutral. You cannot use the ground for neutral. To establish a 120 volt circuit, you need 3 wires...a hot, a white neutral, and a ground which in a cable like Romex NM will be bare copper, and in an extension cord will be green.

You are suggesting to use the a single wire for neutral and ground.....definitely not allowed.
 
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Old 08-04-06, 12:03 AM
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Agreed. No.
 
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Old 08-04-06, 03:05 AM
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I third that NO.
 
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Old 08-04-06, 04:12 AM
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Sorry Jason, no can do.
 
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Old 08-04-06, 08:55 AM
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potentially dangerous (read,; lethal)

additionally, you cannot use a 50 amp circuit for a general purpose circuit
 
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Old 08-04-06, 12:12 PM
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so is there NO WAY or just not MY WAY. to get 120 volt to the center of my building from the existing 240?
 
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Old 08-04-06, 12:19 PM
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Originally Posted by jason9
so is there NO WAY or just not MY WAY. to get 120 volt to the center of my building from the existing 240?
No way to get it from those two existing plugs.

We dont know what else is in the shop, so we dont know what else might work.
 
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Old 08-05-06, 03:15 AM
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if your power system is line-to-line. you can get 120 volts from
240 volts supply. you will need 3 wires... 2 hot wires and 1 grounded neutral. to get 120 volts just connect on 1 hot wire and on the grounded neutral.
 
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Old 08-05-06, 08:13 AM
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If the OP wants to use the conductors (only) from the current circuit, it can be done. One 120 volt circuit is easy and IF the run is in conduit, 2 is possible.

The breaker would have to be replaced with 20 amp (2 pole or 2 single pole). If there is conduit, it can be legally used as a grounding conductor. That would allow the current conductors to be used as 2 hots and a shared neut. The neut would have to be marked accordingly.

If the panel is not the main service. the new neut would have to be reinstalled onto the neut bar rather than the ground bar. If it is the main service panel, they are one and the same.

If there is no conduit involved, OP would be able to have 1 120 volt (20amp)circuit. Use the current conductors as hot, neut, and ground, marking accordinagly of course.

caveat: this is presuming all conductors are insulated conductors. If the ground conductor is bare, it's back to a no-go.
 
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Old 08-05-06, 07:19 PM
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Wouldnt that be considered sharing the neutral?,, and require a 2pole 20A Breaker,,,
 
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Old 08-05-06, 07:22 PM
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A multi-wire (shared neutral) circuit does NOT automatically require a two-pole breaker. It does only if the two circuits terminate on the same device yoke or if 240v loads are served.
 
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Old 08-05-06, 07:37 PM
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Originally Posted by Navydad1
Wouldnt that be considered sharing the neutral?,, and require a 2pole 20A Breaker,,,
Yes that would be shareing a neutral.

No that would not require a 2 pole breaker. If two or more circuits are on the same yoke or strap then they must be handle tied. A 2 pole breaker would be one way to do this.

The neutral could not be spliced by means of the device screws, it would have to be pigtailed to the recs.
 
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Old 08-06-06, 07:07 PM
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The only legal way would be to use a transformer.
 
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Old 08-06-06, 07:37 PM
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Originally Posted by classicsat
The only legal way would be to use a transformer.
Huh??

if what everybody else on this thread is assuming is correct (which the OP has 120 volts to ground and 240 line to line) my method is absolutely legal. I doubt the OP has a low voltage delta that is 240 volts line to ground.

Now that I post this, the op needs to be sure he does not have high leg delta and one of those legs at the recep is the high leg. If so, all that needs be done is to assure that the high leg is not used but the conductor switched to the other 120 to ground phase.


Where would a transformer be needed?
 
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