Triplex problem

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Old 03-02-16, 03:00 PM
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Triplex problem

Hello everyone, I have a problem. I have a triplex wire coming to one of my cattle waterers and I noticed yesterday there was ice over the top of the waterer. I pulled the heater out of the water and it was going but I thought it was not quite hot enough. It is a new heater. I ended up checking the voltage on that circuit and it was 91volts. The other hot wire coming in on the triplex was 143volts. So the two add up to the 230-240 volts but why the difference from 120? Is it possible that somewhere down the line the insulation is compromised and the two lines are "sharing" voltage? Thanks.
 
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Old 03-02-16, 03:21 PM
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Is this a 240 heater? If this is a 240v supply and the third wire is ground the the correct way to measure is between the two hots. If the third wire is neutral then this is wired wrong. For 240v there should be only two hots and a ground.
 
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Old 03-02-16, 03:34 PM
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I don't believe it's a good idea to remove the heater element from the water when it is energized, you will burn the element out.
 
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Old 03-02-16, 03:36 PM
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Hey ray2047, this is a 120v heater. The problem isn't in the heater, it's in the supply line to the area. In fact there is another spot along this triplex supply line where I have similar distortions in the voltage between the two hot lines.
 
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Old 03-02-16, 03:40 PM
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Hey Geochurchi, I agree. I only lifted it out for a few seconds to make sure it was warming. I was holding it in my bare hands. It only got warm.
 
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Old 03-02-16, 03:45 PM
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When one leg goes up while the other leg goes down by the same amount it points to a failing neutral.
 
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Old 03-02-16, 03:46 PM
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Is the Triplex aluminum direct bury? Have you checked voltage at source?
 
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Old 03-02-16, 03:55 PM
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pcboss, How to go about fixing that?
 
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Old 03-02-16, 03:58 PM
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Hi pattenp, The triplex wire is overhead. About 2/3 of the line, which goes to various places and panels, checks out with 120/120. The last leg is the one that's screwed.
 
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Old 03-02-16, 05:07 PM
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this is a 120v heater.... About 2/3 of the line, which goes to various places and panels, checks out with 120/120. The last leg is the one that's screwed.
There should not be 240 volts on the triplex if it is used for 120 volts. There should be one insulated neutral, one insulated hot, and one bare ground.

If you wanted 120/240 you would need quadplex.
 
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Old 03-02-16, 05:19 PM
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There should not be 240 volts on the triplex if it is triplex. There should be one insulated neutral, one insulated hot, and one bare ground.
Triplex is either above ground service drop or below ground service. As a service drop It consist of two phase conductors and a bare neutral messenger, and is meant to provide 120V/240V as a service. When used as a branch feeder it can be used for 240V only or 120V only, not both. I agree with ray2047.

Edit: If the triplex is an old install and is feeding a sub-panel then it may be okay by older code. Four wire feeds to sub-panels is now required.
 

Last edited by pattenp; 03-02-16 at 05:34 PM.
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Old 03-02-16, 06:35 PM
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The neutral may have corroded and may need to be replaced.
 
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Old 03-02-16, 06:42 PM
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This whole installation seems to be non code compliant. Bringing up to code which probably means a new cable would probably fix your problem. Nothing about your description seems correct and we haven't even covered GFCI protection yet. What you have probably shouldn't be fixed. It should be replaced.
 
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Old 03-03-16, 08:33 AM
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Before we go to full replacement, the next step should be to examine the connections to the bare messenger wire. This is probably just a loose connector from the wind and rain at either end of the aerial triplex. Kill the power at the source, and check all of the connections to make sure they're good and tight and don't show any signs of corrosion. If the end of the messanger wire is burned or corroded off, you can cut it off and remake the connection on the new good end if you have enough slack left.
 
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Old 03-03-16, 09:16 AM
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Hey pattenp, this is a non-code farm installation at 40+ years. I guess you could call this part of the line a branch feeder that holds 120v in each conductor.
 
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Old 03-03-16, 09:28 AM
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Hi ibpooks, I think you are probably right about the neutral wire being the problem. I have found corrosion on the split bolt connections before. It's a once every five year tradition finding the connection that is corroded. Usually it's been the conductors but about 3 years ago the problem was definitely the neutral. With that problem there was NO power because of this. The unbalanced power really threw me this time. I would mention again that this is certainly not code. This is an old farm that really couldn't afford the best to start with. Yea the connections are old and the poles are too, and are probably too short, but I just keep mending the little problems. It would cost probably $50,000 to make everything perfect. Thanks so much for the diagnosis, everyone.
 
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Old 03-03-16, 09:44 AM
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Three wire feeds for ag building were allowed by code up until about 10 years ago (not that any family farms have ever been visited by an inspector anyway). They still probably would be if you drew the plan up right. You're allowed to repair the existing stuff without any requirement to upgrade.
 
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Old 03-03-16, 10:06 AM
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You did not say the triplex was going to a breaker panel. You said it was going to a heater. if we are talking about a feed to a subpanel please ignore my remarks.
 
 

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