+ Reply to Thread
Results 1 to 7 of 7
  1. #1
    Join Date
    Oct 2007
    Posts
    9

    Default pop..out goes the light

    Hi,
    I have a ceiling fan (that has a light) in my office that has been working perfectly for the past 2 years or so since i put it in. One thing to note: this is a 1885 house and the fan is on the top floor. the wiring is not new but works just fine.

    Yesterday, i went into the room and turned on the light switch which controls the fan (i have the fan light on - so the switch automatically turns the light on without having to pull the chain on the fan)....when i turned the switch on i heard a pop and the light didn't go on. I didn't notice if the lights went on for a split second and then went off - or if they just never went on.

    i thought - ok - the light bulbs need to be changed - but when i changed them and switched the light on, nothing happened! Here's the weird thing: when i pull the chain for the fan, that works fine!

    So why would the lights suddenly stop working and the fan be fully functional when coming from the same wire? Any thoughts???

    thanks!

  2. #2
    Join Date
    Jul 2010
    Location
    SoCal
    Posts
    6,302

    Default Re: pop..out goes the light

    Take the fan assembly apart - and find out.

    The motor and the light share the same main wall switch, but inside they have 2 leads, usually black and blue - one for the motor and one for the light.

  3. #3
    Join Date
    Jan 2011
    Location
    Columbiana, Alabama
    Posts
    690

    Default Re: pop..out goes the light

    Quote Originally Posted by gemelli2 View Post
    Hi,
    I have a ceiling fan (that has a light) in my office that has been working perfectly for the past 2 years or so since i put it in. One thing to note: this is a 1885 house and the fan is on the top floor. the wiring is not new but works just fine.

    Yesterday, i went into the room and turned on the light switch which controls the fan (i have the fan light on - so the switch automatically turns the light on without having to pull the chain on the fan)....when i turned the switch on i heard a pop and the light didn't go on. I didn't notice if the lights went on for a split second and then went off - or if they just never went on.

    i thought - ok - the light bulbs need to be changed - but when i changed them and switched the light on, nothing happened! Here's the weird thing: when i pull the chain for the fan, that works fine!

    So why would the lights suddenly stop working and the fan be fully functional when coming from the same wire? Any thoughts???

    thanks!
    The fan has a capacitor and motor windings both of which store energy and will created a surge in line voltage when turned on or off.

    The incandesent lamps prior to being turned on have a very low resistance and will draw at least 10 times the current they normally draw lighted. Again a huge surge.

    Power distribution in the US is 60 Hz alternating current. This means when you flipped the wall switch it have been the instant in time where the voltage was at it's maximum. Again a huge surge.

    Any one, or combination, of these factors could be the reason the lights failed.
    Good Luck from Columbiana, Alabama
    Maurice Turgeon, Hidden Content

  4. #4
    Join Date
    Oct 2007
    Posts
    9

    Default Re: pop..out goes the light

    Quote Originally Posted by dj1 View Post
    Take the fan assembly apart - and find out.

    The motor and the light share the same main wall switch, but inside they have 2 leads, usually black and blue - one for the motor and one for the light.
    thanks for your response! I will open it up and look inside - but am i looking for in particular? A loose wire? Something that looks burnt? Sorry...i am a novice!

    And if i did turn it on at the precise moment of a surge, what does that mean? That the light unit is toast?!

  5. #5
    Join Date
    Oct 2007
    Posts
    9

    Default Re: pop..out goes the light

    Quote Originally Posted by The Semi-Retired Electric View Post
    The fan has a capacitor and motor windings both of which store energy and will created a surge in line voltage when turned on or off.

    The incandesent lamps prior to being turned on have a very low resistance and will draw at least 10 times the current they normally draw lighted. Again a huge surge.

    Power distribution in the US is 60 Hz alternating current. This means when you flipped the wall switch it have been the instant in time where the voltage was at it's maximum. Again a huge surge.

    Any one, or combination, of these factors could be the reason the lights failed.
    Hi
    The Semi-Retired Electric - thanks for your reply!

    so ...i could have turned it on at a bad time;-) Are you saying that because of this, the lights are toast and i will have to replace the unit? or ...?

  6. #6
    Join Date
    Dec 2007
    Location
    Tennessee
    Posts
    1,681

    Default Re: pop..out goes the light

    You probably burned the wire off at the lamp socket, that tends to be the weak point. They usually do fail right at turn on because that is when the current is highest, but it was ready to go. It had been getting weaker over time and finally, it was just one turn on away from burning apart. and then it happened, not your fault.

    I recommend that you remove the fuse for this circuit before you work on it. Considering the age of your house, I would be concerned that the wall switch might be cut into the return wore instead of the hot wire. That would be a code violation today, but your wiring could predate the codes. Electricians have been electrocuted because of this.

  7. #7
    Join Date
    Jan 2011
    Location
    Columbiana, Alabama
    Posts
    690

    Default Re: pop..out goes the light

    Quote Originally Posted by gemelli2 View Post
    Hi
    The Semi-Retired Electric - thanks for your reply!

    so ...i could have turned it on at a bad time;-) Are you saying that because of this, the lights are toast and i will have to replace the unit? or ...?
    Well there was no way for you to predict the correct instant to flip the switch. It's like spinning a wheel of chance.

    Have you ever gone into a dark room and flipped a light switch and saw a flash in the switch? Then, flipped the switch ten more times and no flash?

    It's perfectly normal but depending on where the voltage peak in your house is at that moment an expensive surge could result.

    Expensive equipment are designed with "zero cross-over" circuitry which prevents this problem by only permitting a circuit to be energized when the voltage is zero, which occurs 120 times per second.

    Fortunately, your problem is probably just a switch or loose connection.
    Good Luck from Columbiana, Alabama
    Maurice Turgeon, Hidden Content

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •