Adding an Additional Circuit in a Basement

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  #1  
Old 01-18-16, 11:04 AM
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Adding an Additional Circuit in a Basement

First thing I'd like to say is that this is a great forum, full of information and knowledgeable individuals and I appreciate the opportunity to ask for help here.

Now, to why I'm here...

I'd like to add an additional circuit in my basement. I have poured concrete walls and I'm planning to surface mount the electrical in EMT. I'm planning to use 12ga stranded THHN.

I've added circuits before, but have always just used Romex because I was running it through open walls to later be drywalled.

My main question is grounding the EMT. I understand it can be used as an EGC, however it won't be continuous into the panel. I will have 12-2 Romex run through the joists and drop it down to the first outlet on the new circuit, where I would like to ground it to the first Handy Box and hopefully carry the ground through the rest of the circuit without need for a separate ground wire being pulled through. Is this an allowable method of providing a ground?

My second question is regarding the number of receptacles on the circuit. I intend to supply eight duplex outlets on this run (TV and stereo would be the main draws, and a gas fireplace which only requires 2A, when the blower is on, would be in use occasionally in the winter, other devices such as chargers and things may get used from time to time on the other outlets). The only thing on the circuit that might be high-draw would be a blender at the bar, which would be used fairly infrequently. Should I just suck it up and have two separate runs to supply power throughout the basement? I'm running appx 75ft of EMT around the basement.

My third question is about GFCI--from what I understand, as long as the first outlet in the branch is GFCI, everything downstream will be protected as well, as long as it's supplied from the load side. Is this true?

Thanks so much!

Andy
 
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  #2  
Old 01-18-16, 11:08 AM
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Welcome to the forums.

Here's my non-pro 2:
1. I would pull a separate ground wire but this is grey area
2. Number of circuits should be based on anticipated load, there is no rule about the number of receptacles on a circuit - you have certainly been taking this into account so far
3. Yes
 
  #3  
Old 01-18-16, 11:13 AM
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Yes, the ground conductor(s) must securely bond to the metal box at each junction box. The bare ground from the romex must connect to the steel box with a green ground screw. As long as you use the correct EMT fittings, and install them tightly, the remainder of the conduit system can be used as the EGC. At each subsequent box, you will need to run a green or bare jumper from the box green ground screw to the device ground screw. I prefer a separate ground wire, but your proposal is allowed by code.

Code doesn't make a requirement or recommendation as to number of receptacles per circuit. Nothing you described would make me think you need a second 20A circuit.

Your understanding of GFCI protection is correct.

Tip: Don't use handy boxes. They aren't big enough and you can't properly install a ground screw when mounted on concrete. The better choice on unfinished concrete with EMT is 4" square (a.k.a. 1900) boxes with a ground screw "hump" and raised style industrial covers.


 
  #4  
Old 01-18-16, 12:07 PM
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Thanks for the help thus far!

Maybe I'll just buy a roll of that stranded 12-3 THHN--it's only about $35 and then the ground is wired in and I don't have to worry about potentially loose fittings disrupting the ground. I can't seem to find the 1900 boxes on Home Depot's website, maybe they just have them in the stores. I don't like the bulk of the square boxes, but if the Handy Boxes won't work in my situation, I'll have to look at a larger box.
 
  #5  
Old 01-18-16, 01:48 PM
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HD will certainly have them in the store. Looks like the consumer website only has them listed as a case price.

Steel City 4 in. Pre-Galvanized Steel Square Box (Case of 50)-521511234GB - The Home Depot

Other stores have them per unit on the web:

http://www.menards.com/main/maintena...27068818418617
 
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Old 01-18-16, 01:54 PM
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Thanks Ben, I was trying to order everything online and do a store pick up since I have cash back at HD with my Discover card right now. Maybe I'll order most of the stuff today and when I go to pick it up I'll check the SKU and order those online too.
 
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Old 01-19-16, 06:16 PM
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Maybe I'll just buy a roll of that stranded 12-3 THHN--it's only about $35 and then the ground is wired in and I don't have to worry about potentially loose fittings disrupting the ground.
THHN is just a single conductor and is available in both stranded and solid wire. 12-3 generally designates a cable consisting of 3 insulated #12 conductors and 1 bare or green insulated #12 ground. 12-3 NM-B cable is always solid. 12-3 MC cable comes in both solid and stranded.
 
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Old 01-19-16, 07:27 PM
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THHN is just a single conductor
Joe we had a previous discussion about this. There is 3-conductor THWN. It is twisted without a sheath.

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  #9  
Old 01-20-16, 06:11 PM
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Ray, now that you mention it I do kind of remember that product from an earlier thread, but I have yet to ever see any of it.
 
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Old 01-20-16, 06:20 PM
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I think the consensus was it was for cable trays. I can't imagine it being cheaper than individual conductors.
 
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Old 01-20-16, 06:42 PM
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Nice concept and is great for people that don't need 500 foot spools for all three colors.
 
  #12  
Old 01-20-16, 07:02 PM
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Ok, here is some information on it. It appears it is sold retail only and only at Home Depot.

Cabled THHN/THWN - Cerro Retail
 
  #13  
Old 01-20-16, 07:45 PM
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So do we call it 12-2 or 12-3?
 
  #14  
Old 01-21-16, 07:10 AM
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How about Twisted-THHN? THHN Triplex? The "cabled" name in the product title is too confusing -- they shouldn't have done that.
 
  #15  
Old 01-21-16, 08:48 AM
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I was confused when I saw it on Home Depot's web site as to what it was for. They have it in 50 and 100' spools, 12 and 14 gauge, solid or stranded. It is a bit cheaper than buying individual wires in those lengths.
 
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