add switch to bath exhaust fan


Old 05-05-04, 11:58 AM
Thread Starter
Join Date: Dec 1999
Location: Cleveland, OH USA
Posts: 518
add switch to bath exhaust fan

I have a ceiling light fixture in the bathroom but no exhaust fan. Unfortunately, the light is not where the fan needs to be so they will be separate. The wiring is a type where the single wires have thick braided insulation - maybe called knob and tube but I haven't seen tubes around, only knobs.

The light is currently on a switch which looks to be on a switched leg (I hope I use that term properly). That is, only one wire into and one wire out of the box with the switch.

My plan was:

1. remove single gang switch box and use a 2 gang box - one for existing switch and one for a mechanical timer for the fan.

2. Use existing hot feed into switch box and pigtail to both the switch and the timer.

Would this be an acceptable design so far?

Now, what I don't know is what type of wire to use to get the switched hot wire from the timer to the fan. I only need a single wire to go up the wall and into the ceiling since, like the light, for the Neutral (white), I was hoping to tie it into the neutral at the light fixture. Again, what type of wire would I use to go that small distance (5 feet)?

The wall is an outside wall (probably some insulation) and the ceiling is an attic with rockwool insulation blown in.

Sponsored Links
Old 05-05-04, 12:09 PM
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
How old is your house? This does not sound like knob and tube. If it is knob and tube then get a professional to do the work. Adding new wiring to existing knob and tube is not a job for the do-it-yourselfer.

What you need to do is to replace the wire from the light to the fan with three conductor wire. Then you need to run new two conductor wire from the light to where you want the fan.
Old 05-05-04, 12:36 PM
Join Date: Sep 2000
Location: United States
Posts: 18,497
Use existing hot feed into switch box and pigtail to both the switch and the timer.
Do you in fact know that you have a hot feed into the switch box? Not all switch boxes even have one. Some merely have switch loops.
Old 05-05-04, 12:46 PM
Join Date: Sep 2002
Location: welland ontario
Posts: 5,599
Knob tube is best left alone. The minute you try to alter it you are required to replace it. You are not permitted to alter it.

The tubes which you did not see are used to go though joists. Knobs are used to go along joists.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes