conduit and me


  #1  
Old 05-10-03, 03:20 PM
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conduit and me

Hi-

I'm finishing my basement. I've completed framing and I am about to start bending conduit and putting up boxes, and then of course the wiring. A few questions:

1) What is the relationship between using metal conduit, metal boxes, and grounding? Very confused about this after reading all of those DIY books. Since I am using metal conduit and metal boxes and all of this is connecting to my service panel, are my three pronged plugs automatically grounded?

2) I've read that GCFI's for the bathroom in my basement must be on their own circuit. Is anything else allowed to be on this circuit outside the bathroom, or must this circuit be bathroom GCFI's only?

3) If I'm using metal conduit, metal boxes, etc., do I have to have that third grounding wire for my GCFI's? Or does the conduit count as my ground and I only need a black and white wire?

4) If I'm using a dimmer switch to control some lighting, does that require a third wire? What kind of common switches/electrical appliances normally require a third wire?

5) Are there any mistakes that you guys commonly see concerning the placement of conduit? If I have a long run of wall and I'm using long lengths of conduit to feet my plugs, how far above the boxes does the conduit have to be before it bends down into the boxes?

Sorry if I asked too many questions at once. Thanks for your time in advance.

Steve
 
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Old 05-10-03, 04:52 PM
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Is this in your house? Is your framing wood? I only ask because im wondering why your running conduit instread of nm-b.

1.) You need to ground your receptacles to the box, you'll notice that one of the holes in the back of the box is threaded. You need to pick-up some green grounding screws at your local hardware store. Run a piece of bare or green insulated wire from the screw to the receptacle.

2.) Bathroom outlets all need to be on a dedicated circuit with no other loads. unless you only have one circuit running to one bathroom, then you can run other loads within that bathroom on that circuit, but nothing outside of that bathroom.

3.) Your conduit acts as the ground, ground the gfi with the ground screw in the back of the box. Keep in mind that if you use flex in excess of 6' long, it no longer is rated to carry a ground and you must pull one.

4.) You need to be more specific about this. Some dimmers require a neutral, or if its a 3-way switch it will require a third wire.

5.) Theres really no code to this one, but your going to want to run it at least high enough to allow for a 90 degree bend into the box.

Hope i helped you some, post back with anymore questions.
 
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Old 05-10-03, 06:37 PM
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thanks

Yes, all of that did help very much. Thanks for your time. I am running conduit through my 2 x 4 and 2 x 6 framing because my village requires it. I wish I didn't have to, but that's what they're making me do. They're also making us use wire gauge that corresponds to 20A circuits as a minimum thickness of wire. I forgot off the top of my head what that gauge is.

Thanks,
Steve
 
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Old 05-10-03, 06:53 PM
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#12 gauge
 
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Old 05-11-03, 09:55 AM
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If you buy the more expensive outlets which come with a clip riveted onto the mounting ears, that provides the "automatic" grounding of your outlets when using metal conduit and boxes so you don't need any ground wires or pigtails to the metal boxes. If you buy the 39 cent outlets that only have the little cardboard screw holders then you'll need to attach a wire from the ground screw to the box. When you pipe in the walls make sure no point along a wall is more than 6 feet from than outlet.
 
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Old 05-11-03, 10:03 AM
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Thanks Mike
 
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Old 05-11-03, 12:09 PM
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Art. 250.118, Types of Equiptment Grounding Conductors----"The EGC ----enclosing the circuit-conductors shall be one----of the following------(4) Electrical Metallic Tubing"----"
 
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Old 05-11-03, 11:46 PM
josh1
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just a tip: use compression fittings instead of set screw ones. Much much more secure when you tighten them down and cost is minimal. -Josh
 
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Old 05-12-03, 07:18 AM
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Thanks Josh. I'll look into those on one of my next trips to Home Depot....
 
  #10  
Old 05-13-03, 09:09 PM
MTgets
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Josh,

I am going to have to disagree with the type of connectors and couplings.
I have never seen anyone ever use comp. type in a residential interior before. Set screws are just as secure if not more secure and I even believe it is a better method of grounding the piping system.

Also, once the walls are up and painted who is going to be shaking and pulling the pipes?

With comp. fittings, now he has to carry 2 pair of channel locks with him in his pockets/pouch,
Set screw fittings, screwdriver/reamer all in one. Faster and less fumbling.
Labor and time, not material is the budget breaker.
Outside piping? yes you must use comp. fittings. Interior walls? you are better of with set screw.
my 2 cents worth
 
  #11  
Old 05-14-03, 12:32 AM
josh1
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I use big adjustable crescent wrenches to tighten. With silicon sealer.

It MAY take more time, but no one would argue that a wussy set screw offers the same conduit retention strength as the compression fittings. If you are DIYing, you probably dont mind spending 2 minutes and 50 cents for a much better joint IMO. -Josh
 
  #12  
Old 05-14-03, 01:16 AM
MTgets
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Just because I have the most dire need to know, may I ask some questions?

1. What is the silicon sealer for?
2. Are you serious?

Do you get many earthquakes in PA? Floods?
Mabye PVC coated ridgid conduit with meyers hubs would work better for you.

Again, I ask what is the need for such a tight connection? Are you trying to hold water or wires in the pipe? or is that what the sealer is for!!
 
  #13  
Old 05-14-03, 01:34 AM
josh1
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often the threads of compression fittings are not what I would call "well machined" The silicon acts as a sealer and as a lubricant on threads while tightening.

I used ext extra deep aluminum boxes 3/4 conduit to run 2 extra circuits in my basement garage, yes both GFCI protected. Why?

Because a crappy 70 cent steel box is nowhere as waterproof/strong or secure as the ext alum boxes. The faceplates also look much neater as they are the same size as the box instead of much larger than the steel galv box.

Yes it takes time, you have to punch out the mount holes in each box and yes its about 10 times more expensive, but its worth it in my opinion.

Alot of people DIY because we want RESULTS. I am 100% perfectionist. I have never seen PVC coated conduit, but that sounds very rust proof, however straight PVC rigid is fairly strong IMO. -Josh

PS you know how gas stations have those "emergency off' buttons, I was trying to think of a way to install one of those above workbench. For now I use a metal 6 way strip with on/off and breaker plugged into the outlet, as a "kill switch" should something go wrong.
 
 

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