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Thread: Strange lighting situation

  1. #1
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    Strange lighting situation

    My neighbor told me of two issues that I think may be related. I haven't looked at the switch wiring yet, but wanted to do some pre-thinking before I do, in order to save time.

    1. She had an electrician change out a garage fluorescent light for a standard LED bulb type because she complained the fluorescent took too long to turn on, even on warm days. But, the LED takes about 3 seconds to come on, so I'm thinking the problem is not with the lamp or fixture.

    2. She said she also noticed the fluorescent light in the laundry room (garage and laundry room are next to each other so I'm assuming they are on the same circuit), when the switch is off, still shows some dim light from the bulbs.

    I'm thinking these 2 things are somehow related, but I can't figure it out. Could it be that the laundry room fluorescent bulbs need to heat up before the garage light comes on? I can't figure out how that could have been mis-wired that way, but it's the only thing I can think of.

    I'm going to take a gauss reading as my first investigative tool, knowing that the garage light is on a 3-way and I want to know if the original installer used 2-wire Romex for the travelers to save on the cost of 3-wire. This would require "borrowing" a neutral from a source near one of the 3-ways. Not sure how this could cause the issues with the lights, but I'm curious.

    If I can't think of a solution ahead of time, I'll just start opening up switch boxes and trace the problem manually.

    Has anyone ever heard of these issues, and does anyone have any suggestions?

    Thanks in advance.

    Ron

  2. #2
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    Original lamps that were replaced were probably T12 with older ballast. They can take a while to light, especially when cold.
    Some of the LED bulbs don't light instantly, so I would suggest trying a different brand of LED bulb. Try to get a "name brand" such as Cree, GE, Phillips, etc.

    As far as the laundry room, leave your gauss meter on the shelf, it won't tell you anything about the lights. I would first make sure for yourself that the lamps are indeed "glowing" when the switch is turned off. If they are then check things such as wiring to the switch, is the switch a dimmer, lighted switch, etc.?
    If you aim at nothing, you will hit it every time!

  3. #3
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    Quote Originally Posted by Little Bill View Post
    Original lamps that were replaced were probably T12 with older ballast. They can take a while to light, especially when cold.
    Some of the LED bulbs don't light instantly, so I would suggest trying a different brand of LED bulb. Try to get a "name brand" such as Cree, GE, Phillips, etc.

    As far as the laundry room, leave your gauss meter on the shelf, it won't tell you anything about the lights. I would first make sure for yourself that the lamps are indeed "glowing" when the switch is turned off. If they are then check things such as wiring to the switch, is the switch a dimmer, lighted switch, etc.?
    If the lamps are glowing with the switch off, there's a substantial potential between the fixture frame and lamp sockets indicating neutral issues or the fixture is tied somewhere it shouldn't be tied to. I wouldn't even touch the fixture. Get an electrician who knows what they're doing to figure out the problem.

  4. #4
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    Not likely to be the problem here, but some LED bulbs have a driver with a filter capacitor after the rectifier bridge and after you turn the AC off the RC discharge curve can let the LED elements continue to glow, ever slowly dimming, for several minutes. Usually only visible in a dark room. Other driver circuits either turn off positively or contain passive loads to neutral that pull the cap down rapidly below the LED threshold voltage.

    Sent from my XT1585 using Tapatalk

  5. #5
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    Quote Originally Posted by GoldDigger View Post
    Not likely to be the problem here, but some LED bulbs have a driver with a filter capacitor after the rectifier bridge and after you turn the AC off the RC discharge curve can let the LED elements continue to glow, ever slowly dimming, for several minutes. Usually only visible in a dark room. Other driver circuits either turn off positively or contain passive loads to neutral that pull the cap down rapidly below the LED threshold voltage.

    Sent from my XT1585 using Tapatalk
    OP said the bulbs that were staying dimly lit were fluorescent.
    If you aim at nothing, you will hit it every time!

  6. #6
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    Quote Originally Posted by Little Bill View Post
    OP said the bulbs that were staying dimly lit were fluorescent.
    Therefore extremely unlikely to be the problem here.

    Sent from my XT1585 using Tapatalk

  7. #7
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    In a dark room you can see the phosphor continue to glow for several seconds after the light has been shut off. Are you sure that's not what she is seeing?

    -Hal

  8. #8
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    Quote Originally Posted by hbiss View Post
    In a dark room you can see the phosphor continue to glow for several seconds after the light has been shut off. Are you sure that's not what she is seeing?

    -Hal
    That's what I'm thinking as well
    John, Chair City, NC
    Technology: Mans best efforts to make things as good as they used to be

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