Wiring in attic space

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  #1  
Old 09-18-06, 05:29 AM
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Wiring in attic space

I have installed an exhaust fan in my bathroom and now need to connect it to power. The room has only one light switch that controls a single light fixture on the wall and a GFC outlet. I would like to add a second switch to control the fan so it is not always on when the light is on.

I have two questions:
1) Can I run the fan off of the same line as the light switch by installing a double switch in place of the single one?
2) What type of wire do I use, since the run will be in the attic space where it gets very hot in summer and and very cold in winter?

Thanks,
Al
 
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  #2  
Old 09-18-06, 05:53 AM
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Al,

You neglected to tell us where you are located, so it;s hard to respond. You should fill in your profile so we know.

My answers assume the US. If you do not live in the US, things may be different.

First, and most important, you may or may not be allowed to legally use this circuit. Code in the US won't allow you to use this circuit if it is only a 15 amp circuit or if it serves anything in the house outside of the bathroom.

Codes change over the years, and what was legal some years ago is no longer allowed.

As for your actual wiring, that may or may not be possible.

If the receptacle and the switch are in the same box then you could add another switch to supply power to the exhaust fan. However, if the switch is by itself and only wired as a switch loop then you cannot get power from there.

Wiring in the attic is allowed to be non-metallic cable (NM cable), assuming that NM cable is allowed in your area. It is allowed in most areas of the US. The fact that the attic gets hot (or cold) does not matter. However, it is imnportant that the cable (actually the individuals wires that make up the cable) be the correct gage for the circuit. A 20 amp circuit requires 12 gage wire, a 15 amp circuit requires 14 gage wire.
 
  #3  
Old 09-18-06, 07:12 AM
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Sorry for the missing info. I have updated my profile.

I live in Eastern PA.

Thanks for the info.

I have been doing some remodelling in my home. Electrical is the most difficult part.

Even if I opt out of the DIY and decide to get a pro, I would like to be more "how to" aware.

Thanks again.
Al
 
  #4  
Old 09-18-06, 07:17 AM
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Al,

Buy the book "Wiring Simplified". It is available at the big box stores. Then read it. Skip the chapter on farms.

This book will tell you the basics.

If you are doing remodeling, then you generally need to bring the wiring up to CURRENT code. Even if the house was wired when codes were less stringent, remodeling of any significant nature requires that current codes be followed.

With a bathroom remodel, current codes are a must. You may as well bite the bullet and bring the bathroom to code now. In the end you'll be glad you did.
 
  #5  
Old 09-18-06, 07:37 AM
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I actually have that book sitting next to my computer. Bought it a few months ago.

It is the 40th edition and says "Based on the 2002 National Electrical Code". Do I need to get a later version?

Thanks again.....can't wait to get into the pages...
Al
 
  #6  
Old 09-18-06, 07:48 AM
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There is a new edition based on the 2005 NEC, but there are few differences. What will be important is what your town/city requires.

The biggest concern would be whether AFCI circuits are required for bedrooms (most likely yes), and if they have exemptions from the AFCI requirement for smoke detectors. This would apply for bedroom remodeling, and is not a concern for your bathroom remodel.
 
  #7  
Old 09-27-06, 09:14 AM
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Hello again,

I have determined that the bathroom light is on a 20 AMP circuit and that only an outlet in my hallway is on the same line. Therefore my plan would be to put a double switch in place of the current single, and operate the fan separate from the light.

As far as I can tell this is within code, however I plan to bring an electrician to assist (and do some other work for me). I would like to run the wire myself, but cannot find any info on what type of wire is needed in an attic space, since the environment is more like outside than inside.

Also would like to know what "the experienced" do to find the spot where the wire will be routed. In this case I am in an attic filled with blown-in insulation so even the joists are covered. I can ID the wiring in the basement so would it be a dumb idea to run the new wire down next to a vent pipe near by?

Sorry for being such a novice on this stuff.

Thanks,
Al
 
  #8  
Old 09-27-06, 10:27 AM
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>As far as I can tell this is within code

Sounds OK to me.

> cannot find any info on what type of wire is needed in an
> attic space, since the environment is more like outside
> than inside.

The attic temperature in Eastern PA is of no concern for wire type. You would only need special wire if the attic was wet, in which case you would have more pressing problems. Use 12/2g NM-B cable; the cable is typically yellow and sold under the brand name Romex. When you run the cable in the attic, be sure it is installed such that it cannot be accidentally stepped on. The usual way of doing this is running it alongside a 2x4 if you must go perpendicular to the joists.

> so would it be a dumb idea to run the new wire down
> next to a vent pipe near by?

No, that would be OK.

Usually when installing a fan, you would drill down from the attic through the top plate of the wall above the j-box where the switch will be located. Then, drop a heavy string or chain through the hole and try to hook it through the back of the j-box with a bent piece of wire. You could also remove the old j-box to get some more hand room and replace it with an old-work box when you're done. It also really helps to have a helper around when fishing wire.
 
  #9  
Old 09-28-06, 07:58 AM
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Thanks. Great info!
What would we novices do without these forums?
Al
 
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