Electrical Wiring in the Home/Bathroom exhaust fan wiring

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Question
Hi, would appreciate a bit of advice before I go ahead.
I have an exiting bathroom with one switch controlling two lights. I have just added a bathroom exhaust fan to this room and would like to wire this on a separate switch to work independently from the lights. I intend to install a double gang box to have both switches side x side. Since there is already 110V power across the existing switch can I just pigtail connections from there to the new switch to control the new fan? If you happen to have a sketch to avoid miscommunication on my part that would be helpful. Thanks in advance.

Answer
Don,

If there is only one cable (2 wires) in the existing switch box then you can not do what you propose. When you measure the voltage across the terminals of the switch while the switch is "off" you will get 110 volts. However when you turn the switch "on" you will notice the voltage is no longer there. In other words those two wires are providing a "switch leg" for the lights in order to turn them on and off. In order to have full power in your new 2 gang box
you will have to pick up a "steady feed" from the nearest easiest location where ever that is. Could be the attic or the basement. It may not necessarily be the bathroom wiring circuit your currently working with. Any existing lighting circuit in the house is fine that you can easily reach. If that means the current circuit you are working on thats fine. You don't want to go farther than you have to or make it more difficult. Of course you don't want to tap into circuits like a 240 volt AC line or a dedicated 120 volt 20 amp dedicated line for a bath room receptacle. You need to be sure about what it is your connecting to.

Bob  
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PASCACK VALLEY ELECTRIC Bob Mossman

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Licensed Master Electrician (32 years) 6165B Contractor in Closter New Jersey with 40 years total experience in Residential - Commercial - Industrial work. Emergency Service - General trouble shooting and repair work - ONAN & GENERAC generator installation - Paddle fans - Kitchen & Bath exhaust fans - AC lines - Smoke detectors - Telephone lines - Cable TV lines - Computer network cabling - Exterior lighting - Recessed lighting - Security lighting - (200 - 150 - 100 amp service up grades) - Electric Heat - New circuits - New appliance hook ups - and more ! FREE ESTIMATES 201-358-1552 Fully Insured

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Licensed contractor in Closter New Jersey.

Education/Credentials
"The Frank Williams School of Electrical Construction". My dear old boss is 100 ! and still going God Bless him. I started working for "Tenafly Electric" right out of high school at 19. He was tough but I learned more working for him in 8 and half years than most guys. We did mostly industrial work while doing some commercial and residential so I was fortunate to be exposed to all 3 areas of electrical construction. The guys I worked with were all good guys and I stay in touch with some of them still. Most of us went into our own buisness's which says something about the caliber of the guys I worked with. We had some interesting clients : Wella Corp. of shampoo fame, Farah Fawcett etc, I didn't buy shampoo for 10 years. It was a great place to work. Pan Am the former airline just before they went under, another great place to work, nice clean environment. C&C Metals, the largest button manufacturer in the US at that time, a not so clean environment but a very interesting place to work, lots of machine's cranking out buttons of all kinds but you had to be on your toes, it was a potentially dangerous place to be . All kinds of action going on around you.

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