enter image description heretrying to install a new 4 hour timer switch for my bathroom vent. the new timer has 4 wires green (ground) red white and black and they are labeled as to where they should go. but the problem is that there are three black wires currently connected to the old switch and the whites are tied together. I know that I need to tie the whites to the existing whites but I am trying to figure out why there are three black wires in the box all connected to the old switch. on the old switch looking at the back there is one black wire in the top middle which I believe is the hot, one black wire in the bottom middle of the switch which I believe is the load but the third one is attached to the left side top screw could this also be a neutral. hope you can help

  • A photo of the switch would be helpful it sounded like a 3 way to me is 1 screw black and 2 brass colored ones? It could be a jumpered pair as Paul Logan answered but they are usually side by side on a single pole switch.
    – Ed Beal
    Nov 21, 2018 at 17:51
  • how can I send a picure
    – forrest
    Nov 21, 2018 at 20:05
  • Post it to a public site like imager and put a link in your answer and someone will edit it in.
    – Ed Beal
    Nov 21, 2018 at 20:12
  • Can you post a photo looking into the back of the box? Nov 22, 2018 at 0:21
  • having a hard time sending pictures, however the back of the box the whites are all tied together and the three black wires are coming thru the back of the box. my guess is that two of the black wire make a loop to send power to another fixture.
    – forrest
    Nov 22, 2018 at 13:29

1 Answer 1


That third wire is feeding power on to the next item in your house. No worries. Just connect it in with the full time power lead. PCL

  • so what you are saying if I get this correct is to twist the two power leads together allowing the power to continue on.
    – forrest
    Nov 21, 2018 at 20:01
  • and just to make sure the power leads are the hot wires correct.
    – forrest
    Nov 21, 2018 at 20:03
  • That is correct.
    – Paul Logan
    Nov 24, 2018 at 4:14

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