Voltage Drop

Old 07-25-02, 03:24 PM
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Voltage Drop

Went to a buddies house to check his 3 way switch out. Checked the 2 switches first and found only 50 volts to be present. Went down to the breaker panel and checked the load side of every breaker, (Due to the fact that tracing out the wire wasn't possible and the markings on each breaker weren't exactly pinpoint as to which breaker was for what.)
Anyway, got 120 volts off of each load side of each breaker, which leads me to believe there is some corrosion somewhere. This is solid copper wire, not stranded so I pretty much eliminated the idea that a few strands of wire could have broken off inside not allowing enough voltage to get thru. So anyone with any other idea's that I may have overlooked? Thanks
Old 07-25-02, 03:51 PM
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The 50-volt reading is phantom voltage.
Old 07-26-02, 09:22 AM
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I have run into this problem on service calls, it can be very irritating and time consuming to find. Every time this has occurred I have found it to be a loose neutral joint.

I am assuming that you are measuring the voltage from what should be a hot source to neutral. If not then I would say that there is a problem with the equipment ground. Again I am assuming that you even have a grounding conductor present!

One other scenario I have encountered is that one of the three way switches was bad or going bad inside and not making full contact and due to the arcing that had already taken place, I would get eroneous readings on the voltage when I measured hot to neutral. To eliminate this measure hot to ground, provided you have a grounding source present. If you get 120 volts then I would look for a problem with the neutral. If you get the same kind of readings I would look for a problem with one of the switches.

Of course like John has posted, it could be phantom voltage but, it looks like you are having a problem with the lights not working even though you didn't spell that out! If this is true, follow the suggestions I have given you and you will probably find the problem. If not, then at least you can say you have checked those things and come back and see if someone else has any other ideas.

Good Luck, Let us know how it turns out. Highly curious now!!
Old 07-26-02, 11:43 AM
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What is the basic problem? a switch-controlled fixture not operating? If you had only 50 volts at the fixture I'd guess the lamp(s) would appear dim.--Please Post back-thanks.

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