Light switch does not have 120vac across terminals

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  #1  
Old 12-25-11, 11:20 AM
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Light switch does not have 120vac across terminals

Hi; The turn on switch to the Flourescent fixture has been working up to now, but now does not work. checking, there is no 120vac across the switch, when open. There is about 15vac or so. What can be wrong? Switch bad? No, took off wire from terminal, and checked voltage then. Ballast bad? open wire somewhere? Any answers? Thanks. mr.dibs.
 
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  #2  
Old 12-25-11, 11:55 AM
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Check the ballast and for loose connections.
 
  #3  
Old 12-25-11, 01:13 PM
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Have you tried new bulbs? have you redone all wire nuts checking inside them for corrosion. Does power come in at the light or switch. That is were you check for voltage not at the switch. Have you checked that line for 120v.
 
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Old 12-25-11, 03:06 PM
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After you try new lamps, if it still doesn't work, I'd try checking hot to neutral and hot to ground at the ballast connections and then at the power source. The source could be at the switch or at the fixture depending on how the circuit was wired.
 
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Old 12-26-11, 05:25 AM
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Measuring across the two switch terminals (switch on or off) is not the way to measure voltage. You may get various readings but you need to do intermediate calculations and/or additional readings to make use of those readings.

Measure voltage between a test point (terminal in question) and neutral. You can almost always get away with measuring between a test point and ground to get your 120 volts or whatever desired reading.
 
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Old 01-03-12, 01:01 PM
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120 at ballast - light not on. thanks for all.

For all the answers so far, I appreciate them. I have now found that there is 120v at the Ballast white and black wires, but the light does not go on. I only have one light in at the present time. Do I need both lights in for it to work? Or is this type of Ballast, with the starter inside, now not working? Thanks again for all your answers. mr. dibs.
 
  #7  
Old 01-03-12, 03:49 PM
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Try it with two new bulbs.
 
  #8  
Old 01-03-12, 04:48 PM
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Older fluorescent needed both bulbs, new ones will normally light with one bulb.

Are the bulbs fully seated in the tombstones? Is the fixture grounded?
 
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