Just curious


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Old 02-18-13, 06:40 PM
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Just curious

Im mostly curious as to what would cause this condition. I have an exterior UF rated wire buried 18 going about 30 feet from the house to a septic aeration system(20A circuit 12-2 wire). The motors not running so I did a voltage check at the receptacle supporting the motor with an analog tester that reads around 110 volts. A cube circuit tester shows the receptacle to be wired correctly but the motor wont run, nor will a corded drill start when plugged into the same receptacle. The voltage at the jb before the wire leaves the house is 121 volts.

I disconnected the UF wire at the junction box inside the house and did an ohms test on the individual conductors. The white neutral wire reads around 25 ohms and the black and bare ground read no resistance.

I plan on digging a new trench and replacing the existing UF with conduit and new wire but Im curious as to why I see a low voltage and high ohms resistance on the wire and the motor wont start. Is there a break in the wire that allows voltage and ohms to register but under load fails?
 
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Old 02-18-13, 06:46 PM
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Connect your voltmeter to the line again and then plug in a drill and squeeze the trigger. Does the voltage change ?

My guess is you just about lose all voltage.
That would indicate some type of break....like you suspect.
 
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Old 02-18-13, 07:38 PM
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A marginal connection would register voltage, but would not be enough to run anything connected to it.
 
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Old 02-18-13, 07:59 PM
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Thanks for the replies. When I did the ohms check on the wire there were no wire connections, it was just the length of under ground UF wire. What I did was connect the white and black wires first and tested the other ends which read 25 ohms. Connecting the white/bare was the same at 25 ohms and for a sanity check, the black/bare read 0 ohms. So I'm guessing a break in the (white)wire would react the same as a bad connection?
 
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Old 02-18-13, 09:16 PM
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Yep.....sounds like a break in the white wire......probably corroded as it is making a partial connection.
 
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Old 02-19-13, 05:34 AM
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You have a break in the white wire somewhere. On the bright side there are UF splice kits that can be used underground. You just need to find the break.
 
 

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