220 leg going to ground

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Poncho

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I installed a 220 v 40 amp feed to my yard shed 3 years ago using underground. Two 20 amp breakers, one for receptacles, one for lighting circuit. OK until Jan this year when I noticed an unexpected increase in the utility bill. I did some welding and used a space heater during that time.
While trouble shooting I found a current draw on lighting circuit with no load on it. Also, voltage from L1 to ground is 220 while L2 to ground is zero. The lights inside shed as well as flood lights outside work fine as do the two 3 way switches and the one 4 way switch.
When lighting breaker is pulled, voltage returns to normal on L1 an L2. What up?
 

hj

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You CANNOT have 220/240 from either L line to ground, UNLESS the ground is at the potential of the other L(ine). If the ground is at L2s potential, (which could also happen if the ground is nonfuctional and the light is connected to line L2 and turned on), then it would have 220 to L1 and zero to L2, but the ground would also have to be "broken" or it would be an immediate short circuit and trip the breaker. Check the continuity of your ground wire.
 

Poncho

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You CANNOT have 220/240 from either L line to ground, UNLESS the ground is at the potential of the other L(ine). If the ground is at L2s potential, (which could also happen if the ground is nonfuctional and the light is connected to line L2 and turned on), then it would have 220 to L1 and zero to L2, but the ground would also have to be "broken" or it would be an immediate short circuit and trip the breaker. Check the continuity of your ground wire.
Not sure I understand all the info except the "broken ground" part. Thanks
 

Jadnashua

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You do not have 120vac coming into your house, you have 240vac with a center-tapped transformer feeding your home with the neutral connected to that center-tap. You get 120vac because you have half of the path through the transformer as a return path. At the entry point to the house, the neutral and ground are connected together. There should never be any current on the ground wire, it is there for safety and to provide a path to trip a breaker or blow a fuse. If L1 OR L2 was really connected to ground, you'd have a short circuit, and it would trip the breaker or blow a fuse. HJ is right on, if you're measuring 220vac between anything and ground, the ground at the other end of the supply is open or broken somewhere in between.
 

WorthFlorida

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Is your welder a 120v or 220v ? If you still getting that weird voltage reading, unplug the welder and check it again. Do you have any LED lights, timers or dimmers?
 

WorthFlorida

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Second thoughts, something may be wired wrong with the three/four way light switches?

Where is the voltage being measured at? At the shed or at the house breaker panel?
 

Cacher_Chick

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I am surprised that no one has mentioned that it is not permitted to pull 240V to an outbuilding without having a properly installed subpanel in said building.
 

hj

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He specified a dp 40 amp and and two sp 20 amp which would indicate it IS a subpanel unless he ran two wires and interconnected them somehow.
 
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Cacher_Chick

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HJ,
If that were the case he would have a grounded conductor and a grounding conductor coming from the main panel, so if the connections were made properly, as you mentioned, there would be no way to measure 240v between one hot leg and "ground".
 

Jadnashua

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HJ,
If that were the case he would have a grounded conductor and a grounding conductor coming from the main panel, so if the connections were made properly, as you mentioned, there would be no way to measure 240v between one hot leg and "ground".
Ground is connected to neutral at the main panel, so yes, he would measure a voltage unless the wire is open.
 

Cacher_Chick

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Ground is connected to neutral at the main panel, so yes, he would measure a voltage unless the wire is open.

He claims to have measured 220V between L1 and "ground", which you and I know is not possible if his "ground" is properly connected. He would have to have an open ground which is also shorted to L2 in the portion of the circuit that is connected to the tester.

It might be good to know if the OP is using a known-good voltmeter also. Some people put faith in other testing tools which I would not trust.
 
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Jadnashua

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Best I can think of, it would take more than one fault for that to happen. In a home, there is NO valid situation where you can get 220vac to ground. Now, some high impedance DVMs might make it look like it, but not in reality. In a correctly wired 240vac system, the most you could ever measure would be 240vac L1-L2. Anything from L1 or L2 to ground OR neutral would be 120vac. If neutral was open, some weird things can happen.
 

Poncho

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You CANNOT have 220/240 from either L line to ground, UNLESS the ground is at the potential of the other L(ine). If the ground is at L2s potential, (which could also happen if the ground is nonfuctional and the light is connected to line L2 and turned on), then it would have 220 to L1 and zero to L2, but the ground would also have to be "broken" or it would be an immediate short circuit and trip the breaker. Check the continuity of your ground wire.
hj , you are astutely correct sir. Found the open ground and fixed. Owe you a drink at your favorite imbibing concern. Thank you for helping me.
 

Poncho

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Good to see someone actually reads my postings and acts on them.
hj, wonder if I may bother you with something of interest...to me at least. I have been researching my Residential electric meter dynamics and have become "stumped" on some of my findings.
The meter evidently is an Electro-Mechanical-Inductive type with 3 coils, 1 above the Aluminum Disk fed from L1 & L2 that creates a Shunt Magnet in the ferrous framework around the AD and 2 smaller coils in series under the AD fed also from L1, L2. Also, on one side of the AD is a Brake Perm Magnet that, supposedly, prevents the AD from spinning when current flow is interrupted.
To makes matters murkier, to me , 3 copper bands surround the Shunt Mag, 1 on either side of the top coil and 1 on the portion of the SM coil that extends to just above the AD.
Now, the Physics as I understand it, is that Magnetic Eddy Currents are created and act upon the AD in relation to current on L1,L2 causing the AD to spin. How is this possible because the AD is, well, Aluminum and to my thinking cannot be influenced by a magnetic field?
 

Reach4

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Now, the Physics as I understand it, is that Magnetic Eddy Currents are created and act upon the AD in relation to current on L1,L2 causing the AD to spin. How is this possible because the AD is, well, Aluminum and to my thinking cannot be influenced by a magnetic field?
You agree there are currents. Those currents generate magnetic fields. The magnetic fields interact with other magnetic fields.

Take a really strong magnet, and sweep it quickly across a US quarter, without touching. You will feel the resistance in your fingers that are holding the magnet.
 

Bluebinky

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Now, the Physics as I understand it, is that Magnetic Eddy Currents are created and act upon the AD in relation to current on L1,L2 causing the AD to spin. How is this possible because the AD is, well, Aluminum and to my thinking cannot be influenced by a magnetic field?
I'll give it a shot...

Materials have magnetic classifications, diamagnetic, paramagnetic, and ferromagnetic. Aluminum is, I believe, paramagnetic meaning it will be slightly attracted to a magnet.

Electrically conductive materials will interact with varying/moving electromagnetic fields.

The difference between the two is a matter of scale, and is determined by the geometry of electrons circling individual protons vs the geometry of eddy currents in a conductor.
 

Poncho

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I'll give it a shot...

Materials have magnetic classifications, diamagnetic, paramagnetic, and ferromagnetic. Aluminum is, I believe, paramagnetic meaning it will be slightly attracted to a magnet.

Electrically conductive materials will interact with varying/moving electromagnetic fields.

The difference between the two is a matter of scale, and is determined by the geometry of electrons circling individual protons vs the geometry of eddy currents in a conductor.
That kinda makes sense...except the "eddy current" part. Thank you for taking the time to be helpful!
 
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