Puzzled about fuse box voltages

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Old 03-11-17, 12:56 PM
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Exclamation Puzzled about fuse box voltages

Ok I have a general switch fuse box. One side has 140v and 100v on the other. This only happens when major appliances are turned on. This meaning furnace microwave etc. But when only lights is on its 120v at main and outlets. On 1 leg I get power to neutral and power when checked with volt meter.
 
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Old 03-11-17, 01:16 PM
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Are those appliances 240 volts? What is your reading across the hots in the fuse box.
 
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Old 03-11-17, 01:21 PM
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No the appliances are 115-120v. Not sure just checked it on the sides that I got 100v on 1 side and 140v on the other
 
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Old 03-11-17, 01:22 PM
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Check across the the two incoming hots to see what the service voltage is.
 
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Old 03-11-17, 01:24 PM
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How do I set my volt meter for that to get it right. or is it just put black on 1 side and red on the other
 
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Old 03-11-17, 01:31 PM
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Sounds to me you have a loose or bad neutral. That will show up when there's a heavier load than just lights.

Make sure the meter is set to voltage high enough to measure 300V and test across the two legs (red and black). It doesn't matter to which legs you place the red and black test leads to.
 
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Old 03-11-17, 01:33 PM
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Multimeter should be set to 300 volts or higher. Yes put your probes on the two incoming lines.
 
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Old 03-11-17, 01:33 PM
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how do I check that with a volt meter.
 
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Old 03-11-17, 01:36 PM
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So I have a steady flow of 247v coming in when appliances are on.
 
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Old 03-11-17, 01:39 PM
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Checking the neutral is done by inspecting the neutral connections not using a multimeter. Once you confirm ~240 volts you will need to call the electric company emergency number and ask them to check the connections on their side.

Edit: Your voltage is good. Call the electric company now.
 
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Old 03-11-17, 01:40 PM
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With 247V you should have a fairly even split between the two legs to neutral, 124V/123V or close to that. If one leg is low and one high such as 147V/100V then you have a service neutral problem and need to have it fixed.
 
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Old 03-11-17, 01:40 PM
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but wouldn't that show up on the main coming in if it was the citys side
 
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Old 03-11-17, 01:43 PM
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You need to check the voltage where the service enters the mainpanel from the meter.
 
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Old 03-11-17, 01:45 PM
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what am I looking for there when I check it
 
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Old 03-11-17, 01:47 PM
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Even split voltage on both legs to neutral. Such as 123/124, not 147/100.
 
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Old 03-11-17, 01:50 PM
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Do you have an aerial (overhead) service ?
The problem is most likely at the service head.

Turn off any valuable electronic equipment because it's in danger if it's on the high voltage side.

The problem here is not that the two legs are changing voltage because they are not. What is changing is your neutral is no longer at 0 volts.
 
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Old 03-11-17, 01:52 PM
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no my wire is buried underground
 
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Old 03-11-17, 01:54 PM
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I had to deal with this same problem recently. I had voltage of about 100/145 and lights would flicker when any heavy load would kick on. I had a bad aluminum underground cable where the insulation got nicked during install and the wire turned to mush.
 
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Old 03-11-17, 01:56 PM
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that's great to know being the ground is froze hard as a rock.
 
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Old 03-11-17, 01:59 PM
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Call the power company emergency number.

Usually the power company is responsible up to the meter pan.
 
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Old 03-11-17, 02:00 PM
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the buried part is after meter so its on me
 
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Old 03-11-17, 02:01 PM
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When I called my power company they were there that same day to fix.
 
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Old 03-11-17, 02:01 PM
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So is the electric companies service a drop?
 
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Old 03-11-17, 02:04 PM
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the buried part is after meter so its on me
That sucks. Make sure the voltages are out of whack on that feed from the meter. You still need power company to check service drop to meter.
 
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Old 03-11-17, 02:07 PM
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This place was made in 1970 with original box. It has the box on the pole from the main. Then a buried wire to another box with 2 plugs, then to my inside panel box. So I have 3 panel boxes after meter. yes the citys is a drop in line.
 
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Old 03-11-17, 02:13 PM
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So do I test the outside box the same as the inside panel box
 
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Old 03-11-17, 02:18 PM
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Yes... you can check the outside boxes. You're responsible to the meter pan.
 
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Old 03-11-17, 02:19 PM
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ok so just check the 2 main hots on the inside of the box
 
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Old 03-11-17, 02:33 PM
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Ok so I checked the out on my fuse bo from pole its a constant 247-244v. But I checked the next box in line that has an outlet when furnace is on it reads 98v.
 
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Old 03-11-17, 02:36 PM
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Question

This is where the underground wire comes up from main line to house
 
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Old 03-11-17, 02:48 PM
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At the first disconnect after the meter check the voltage between the legs and neutral. Checking the total voltage at 240 doesn't tell you a thing. You need to see if there's an imbalance between the two legs and neutral.
 
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Old 03-11-17, 02:53 PM
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how do I check amps someone said the fuses maybe over loading
 
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Old 03-11-17, 03:23 PM
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You need to be methodical in your testing. Test the voltage on each leg to neutral on the load side from the meter before the first main fuse/breaker, then test the same way after the first main fuse/breaker. Move to the next connection/panel point and do the same until you find where the voltages are imbalanced. You need to figure out the first point where the voltages between the legs to neutral are greatly different.
 
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Old 03-11-17, 03:23 PM
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To check amps you need a clamp on meter, but that is not your issue. You have a loose neutral.

At the pole box check between each hot to neutral. They should both be something around 120 volts. If it is not correct there then it will be on the power companies side and you need to call Otter Tail power's emergency number and tell then you have a loose neutral. It was extremely windy Monday and Tuesday (50 - 60mph gusts) so it wouldn't surprise me that some connections came loose.
 
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Old 03-11-17, 05:49 PM
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Just a quick update: I reached out to Nicholas by PMing him as he lives in MN. Communicating with him I found out he has a pole mounted meter (overhead) with a main fuse pullout below. This is a rural setting with a mobile home on the property. From the main on the pole it goes underground to a panel near the mobile home with two 50 amp receptacles on it. The mobile plugs into one (of two) 50 amp receptacles which feeds a panel inside the mobile home. Each receptacle has its own 40 am fuse block.

The issue lies in the MH panel. He sent me a picture and the neutrals are burned and corroded. He is going to install a new neutral bar for now and possibility a new panel at a later date.

I just wanted to make sure you guys get the info as I always like to know the outcomes as much as, I would assume, you do.
 
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Old 03-11-17, 06:01 PM
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Good job.....thanks for the update.
 
 

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