job trailer wiring

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Old 11-22-07, 08:23 AM
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job trailer wiring

hey have wired my job trailers with electrical outlets, but I cant seem to figure out the feed. My local electrical provider gives us temp power boxes with a 220v 20 amp breaker and a conventional 3 prong plug to access it. I am assuming from what I know about electrical that I only have two hot leads and a ground at that outlet, which leaves me without a neutral in my box in the trailer. This might be the reason my tools run really fast and only when two are plugged in (I wired two seperate 120 v breakers 4 oulets). I think I need a neutral????? would this be the existing ground from my temp power?????


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Old 11-22-07, 08:28 AM
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The term "conventional three prong plug" means nothing. tell us exactly what you are supplied.

The electric company provides two hots and a neutral. The electric company does NOT provide a ground.

You need to wire a neutral. Not doing so will quickly destroy the tools you are trying to use, could kill you and is very unwise. If your tools are running fast then your have made your wiring wrong.
 
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Old 11-23-07, 02:10 PM
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the plug is a small three prong with one straight blade turned .......is the nuetral on what would be the round ground prong?.........thanks again for keeping us newbies alive
 
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Old 11-23-07, 03:09 PM
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Neutral is never the ground. With only two non-ground prongs it can only be 240v or only be 120v. It can not be 120/240v. If it is 240v you can not use it for 120v equipment. Does the plug look like any of the pictures here: http://www.apcmedia.com/salestools/S...NRML_R0_EN.pdf
 
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Old 11-23-07, 06:38 PM
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the plug receptical on the power company box is I guess is c 19 /c20 and there is a double pull 20 amp breaker in the box. I was thinking I could use this as a feeder for a sub panel.......am I wrong. the plug has a hole at bottom and one flat blade, and one "T" blade
 
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Old 11-23-07, 10:08 PM
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I doubt those are it. They are international not US. Try table 4. Is it NEMA 6-15P?
 
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Old 11-24-07, 08:10 AM
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I guess it would be the nema 6- 20 then because the outlet is attacted to a 20 amp double pull breaker it looks like the difference is between the 20 and 15 is the side of the flat blade
 
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Old 11-24-07, 09:02 AM
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I suspect that you have two 120 volt receptacles, each ca[able of supplying 20 amps.
 
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Old 11-24-07, 10:48 AM
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What voltage do you get when yo measure across the two flat blades? Have you asked the PoCo?
 
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Old 11-24-07, 06:03 PM
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Talking to the power company I guess would be the next step, I know in the past they have given us a twist lock outlet instead of what we have now.....and that has been 220. I just assumed since it was a double pull breaker that it was 220 coming out that single outlet. the poco provides us with 4 120 recepticles on the other side....... off two other breakers....... i will keep ya posted and try to test that plug in tomarrow......what should I be looking for when i test it?
 
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Old 11-24-07, 06:13 PM
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Originally Posted by racraft View Post
I suspect that you have two 120 volt receptacles, each ca[able of supplying 20 amps.
there is only one plug in...........
 
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Old 11-24-07, 10:26 PM
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You would be checking if the voltage across the two flat blades was 120v or 240v. From your description it could be a 20a 120v as Bob thinks or, since you have 120v outlets on the other side it could be 20a 240v. If you need to run a 120/240v subpanel it is all academic anyway because you would need a four prong plug and that you don't have.
 
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Old 11-26-07, 08:10 PM
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this might be the answer

I thikn we are getting there...with only 3 prongs out, I can't wire to a sub pannel......I think thats where we were trying to get.....I will have to talk to the poco and get them to give use a different system...thanks for the help guys
 
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