220 outlet pulling 400 volts

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  #1  
Old 03-19-13, 03:22 PM
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220 outlet pulling 400 volts

This thread is two similar threads by the same poster that have been combined.

I recently installed a 220 outlet in a new guest house. One side is reading about 140 volts and the other side is reading nearly 300 volts. What is causing this?
 

Last edited by ray2047; 03-19-13 at 03:45 PM.
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  #2  
Old 03-19-13, 03:25 PM
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110 outlets pulling 280 volts

Why are my outlets reading 280 volts?
 
  #3  
Old 03-19-13, 03:29 PM
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Where are you taking your readings from? You need to unplug everything until you get this sorted out.
 
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Old 03-19-13, 03:32 PM
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Where are you taking your readings from? With what instrument are you taking your readings? Sounds like you miswired this as well as the other receptacles in your house per your other post. The problems may be tied together....literally.
 
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Old 03-19-13, 03:32 PM
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I'm taking the readings from each individual outlet. Everything s unplugged
 
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Old 03-19-13, 03:35 PM
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Go to your other post and give us the information as to how that was wired. Take pictures of the wiring in the panel if you can as well as the receptacle. http://www.doityourself.com/forum/el...your-post.html
 
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Old 03-19-13, 03:35 PM
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The two circuits were run separately. I'm using an analog multimeter.
 
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Old 03-19-13, 03:37 PM
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No 110 volt receptacles in the US, only 120, 208, and 240. You would not have 208 on a residential single phase circuit. In addition to Chandler's question are you using a digital multimeter? If so change the batteries. If this is a 3 phase service let us know.
 
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Old 03-19-13, 03:38 PM
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Where are you putting the probes? Got pictures of the panel and receptacle as it is wired? Even though you wired them separately, you got something messed up causing problems on both. Measure the voltage in the panel from the main to the neutral buss. Give us both readings on each lead of the main.
 
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Old 03-19-13, 03:39 PM
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15 amp breaker with 12/2 wire to the 110 outlets.
 
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Old 03-19-13, 03:41 PM
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Ray, before I go bonkers, combine his posts if you see fit, please.
 
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Old 03-19-13, 03:42 PM
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Did it before you posted Larry. You just type too fast.
 
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Old 03-19-13, 03:44 PM
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Where would you source 400 volts in a residence or even 300 for that matter? I can't figure out a wiring screwup that would change 240 volt service to 400 volts. Are all the 120V receptacles on that circuit measuring the same? How about receptacles on other 120V circuits?

I'll ask the dumb question - meter voltage select to AC and ranged correctly? Take your meter to a neighbors house and make sure that it's working properly. Step 2 measure the voltage at your SEP to see what the POCO is giving you.
 
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Old 03-19-13, 03:45 PM
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Oops... 120 outlets. I'm in AZ, USA
 
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Old 03-19-13, 03:48 PM
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Could the erroneous high voltage be explained by reading the wrong analog scale?
 
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Old 03-19-13, 03:49 PM
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I'm putting the probes into the plug. On the 120 plugs: red in the left, black in the right.

On the 220 outlet, I'm measuring black in the ground and red on either the left or the right hot.
 
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Old 03-19-13, 03:53 PM
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I'm pretty sure I'm not reading the wrong scale. The problems are occurring in the guest house. I have tried the meter in my main house and all the readings are within normal range
 
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Old 03-19-13, 04:09 PM
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In the beginning.......let's start there. Measure each side of main to neutral buss. Give us the values.
 
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Old 03-19-13, 04:19 PM
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Ground to left = 150
Ground to right = 270
Left to right is more than 300
 
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Old 03-19-13, 04:22 PM
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On the 220 outlet, I'm measuring black in the ground and red on either the left or the right hot.
No, incorrect method. You measure between the two hots not to ground. Which probe to which slot doesn't matter on AC but you do need to measure between the (hot) slots not to the ground.

In addition to:
Measure each side of main to neutral buss. Give us the values.
Measure between the two mains.
 
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Old 03-19-13, 04:25 PM
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Between the two mains, it registers over 300 which is the highest value on the meter
 
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Old 03-19-13, 04:31 PM
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Between the two mains, it registers over 300 which is the highest value on the meter
Then you need to shut off the main breaker and call the electric company 24 hour emergency number now.
 
  #23  
Old 03-19-13, 04:58 PM
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Something is very wrong here. If the voltages were that high the smoke should have come out of all the equipment in the house.
 
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Old 03-19-13, 05:18 PM
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If the voltages were that high the smoke should have come out of all the equipment in the house.
Including his meter!

I doubt analog meters would be affected by this, but one time I was getting some crazy readings on my Fluke digital meter and it turned out to be the internal 9volt battery.

I agree with the previous post: Call the power company NOW! It is free for them to check the incoming lines.
 
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Old 03-19-13, 06:31 PM
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Let us know what they say, please. You have called them, right??
 
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Old 03-19-13, 09:26 PM
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Well, no one made the local news for being electrocuted to death at home yet...

First thing I'd do is to check with another meter. I've had meters that weren't terribly accurate, even one that should have been halfway decent.
 
  #27  
Old 03-20-13, 02:49 AM
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OP says readings were normal at his house, but these readings are at his guest house, so hopefully he called the POCO and got things in order. Sounds more like a bad transformer winding, BUT why wouldn't it have affected his house similarly?
 
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Old 03-20-13, 04:32 AM
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Would a floating neutral create this situation?
 
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Old 03-20-13, 04:53 AM
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A floating neutral would still be limited to the system voltage of 240 max on one leg. I have never seen one that imbalanced.
 
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Old 03-20-13, 08:29 AM
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Thanks everyone for your suggestions. I did end up calling a professional and it turns out that I had plugged the breakers into a delta high leg. I hope I got that name right. Anyway, it was a simple fix. We just had to move the breakers to a different leg/line. I can't use every 3rd slot unless its for my A/C unit.
 
  #31  
Old 03-20-13, 08:43 AM
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From my very first post:
If this is a 3 phase service let us know.
If you had only answered that question we would have probably gotten you fixed up quickly. You were right to call a pro and given the fact you have three phase it would be a good idea perhaps to let the pros handle your electrical needs.
 
  #32  
Old 03-20-13, 05:04 PM
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Just curious, what type 3 phase service can give you over 300 volts phase to phase, but still provide a 120 volt phase to neutral. I didn't think that was possible with the common 3 phase voltages, 120/240, 120/208 or 277/480.
 
  #33  
Old 03-20-13, 05:31 PM
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Ground to left = 150
Ground to right = 270
Left to right is more than 300
He was reading from hot to ground. In a 277/480 Wye system you would read close to 300 volts from phase to ground, and more than 300 between phases (480).

I am still not sure we had all the info because, with a 120/240 delta high leg system, you would read 240 between phases and 208 from the high leg to ground.
 
  #34  
Old 03-20-13, 05:31 PM
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It's more than likely an open high leg delta service. Also called red leg.

Its a derived 3 phase service in an area where none exists. Say you wanted 3 phase service at your garage but it was in a residential neighborhood. There would most likely only be single phase service.
So there would be a large transformer supplying the basic 120/240 service. (Phase A & C) Then there would be a second transformer connected to one of the 240 hot legs and I believe neutral. This second transformer is usually smaller and supplies a smaller amount of 3 phase service. The output of this transformer is the derived B phase. Between the phases.... the voltage is even but between that B leg and ground it's high. Sometimes near 300 volts.

Hence the name. B*astard leg or red leg.

Strange thing..... this service is rarely ever found in a residence.

Since this type of service does strange things with phase angles......not all meters can read it correctly.
 
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Old 03-20-13, 06:01 PM
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Thanks for the explanation guys, that's a strange setup for a residence.
 
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