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-   -   Getting New Home Runs Into Attic (http://www.diychatroom.com/f18/getting-new-home-runs-into-attic-153280/)

Thadius856 08-10-2012 11:17 PM

Getting New Home Runs Into Attic
 
Just pulled 7 home runs for kitchen remod. All come across the attic and come out in a 1.5" hole in a rafter blocking. I have about 15' hanging on each 12-2.

The problem is I have farther than 24" to get into the panel, so i dont get the nipple exception to my conduit. Since they're required to be 20A (except the lughing circuit?) i dont have any room for derating.

Is my only choice to run three separate EMT 3/4" and drill new holes in the side of my panel?

Edit: would a junction help me at all?

k_buz 08-10-2012 11:40 PM

If you are using romex, you can use a romex connector and forgo the conduit.

Thadius856 08-10-2012 11:57 PM

To be clear, this is the main panel on the outside of an exterior wall and I'm trying to get them up fom the panel and into the attic through the rafter blocking.

stickboy1375 08-11-2012 12:37 AM

Quote:

Originally Posted by Thadius856 (Post 985938)
To be clear, this is the main panel on the outside of an exterior wall and I'm trying to get them up fom the panel and into the attic through the rafter blocking.


This is what I would do, either open up the sheathing behind the main panel to get the new circuits into the panel with separate NM connectors, OR do a pipeline from the main panel to the attic, with approved jboxes and thhn...

Thadius856 08-11-2012 01:17 AM

I'll try to get into the wall in the morning. Going to be tough. Will see what I can do.

bobelectric 08-11-2012 05:39 AM

F'ed up eh? Don't hide mistakes where down the road nobody can find them.

Thadius856 08-11-2012 10:11 AM

Not trying to hide anything. If pulling them into the stud bay behind the main panel and bringing tem through the back isn't the right way to do it, please let me know. I definitely want to Do It Right. That's why I'm asking here and not just hacking things in willy nilly. :)

Is the 3x 3/4 emt route better?

Is 1x 2" sch 40 PVC with jb 20" up better?

Is there a better way I haven't considered?

Thadius856 08-11-2012 10:20 AM

If I went the THHN route, #12 is would be derated to 70% (7-9) for 21A.

Neutrals don't count as current carrying conductors in this case.

I'd need to pull white and green, and one other color that should probably be black or red but doesn't have to be if I remark it.

Is this all correct?

To keep the cursing to a minimum, what size conduit would you recommend I pull these through?

stickboy1375 08-11-2012 10:26 AM

Quote:

Originally Posted by Thadius856 (Post 986104)
If I went the THHN route, #12 is would be derated to 70% (7-9) for 21A.

You wont have any derating issues until you cross over 9 conductors.

Quote:

Originally Posted by Thadius856 (Post 986104)
Neutrals don't count as current carrying conductors in this case.

Only if they are multi wire branch circuits.

Quote:

Originally Posted by Thadius856 (Post 986104)
I'd need to pull white and green, and one other color that should probably be black or red bu doesn't have to be if I remark it.


You need to pull a neutral for every two ungrounded (hot) conductors...


In your example, you have 7 circuits, im just assuming they are all two wire circuits, you would need to run 7 hot conductors and 4 neutral conductors and 1 ground sized to the largest branch circuit you already ran to the kitchen. Only ONE of the neutrals would be considered current carrying. Giving you a total of 8 current carry conductors.


3/4 EMT with 12 #12AWG conductors is only a fill % of 28.96%, so the jam probability is very small... Personally I would pull one spare wire to complete the last multi wire branch circuit, meaning, I would pull 8 hots, 4 neutrals, and 1 ground... you must pair up these wires as to ensure you don't over load any of the neutrals, they must be landed on opposite phases for the neutral current to be cancelled out.

Thadius856 08-11-2012 11:10 AM

Awesome! The only nasty part will be making all these connections in an unfinished attic.

I'm with you until the very last part. I want each of the 4 neuts to share one leg from each phase. How can I determine which breaker is on which leg? Silly question, I know...

k_buz 08-11-2012 11:15 AM

I wouldn't switch over to THHN. I would install as many sleeves as necessary (4 3/4 PVC). You are just asking for trouble with all those splices.

stickboy1375 08-11-2012 11:17 AM

Quote:

Originally Posted by Thadius856 (Post 986138)
Awesome! The only nasty part will be making all these connections in an unfinished attic.

I'm with you until the very last part. I want each of the 4 neuts to share one leg from each phase. How can I determine which breaker is on which leg? Silly question, I know...

Just use two pole breakers and you will be fine. :) and label your hots so when you are in the attic, you know how to pair them off. (example... label the conductors, 2,4 6,8 10,12 14,16.... this way you know 2 & 4 share a neutral which would also be labeled 2,4... This will ensure that you keep everything in check.

stickboy1375 08-11-2012 11:23 AM

Quote:

Originally Posted by k_buz (Post 986141)
I wouldn't switch over to THHN. I would install as many sleeves as necessary (4 3/4 PVC). You are just asking for trouble with all those splices.

You cant do that, code wise... ;) And I think the OP will be fine as long as he takes his time and labels all the thhn's....

k_buz 08-11-2012 12:23 PM

Quote:

Originally Posted by stickboy1375 (Post 986149)
You cant do that, code wise... ;) And I think the OP will be fine as long as he takes his time and labels all the thhn's....

For my information...why? We don't do alot of meter/main's round here so I'm not up on the ins and outs of it. Its not underground so its not considered a wet location.

stickboy1375 08-11-2012 12:29 PM

Quote:

Originally Posted by k_buz (Post 986184)
For my information...why? We don't do alot of meter/main's round here so I'm not up on the ins and outs of it. Its not underground so its not considered a wet location.

Check out 312.5 (C) Cables. It can be legal, but rarely is... you have to meet 7 criteria's

This applies to Cabinets, Cutout boxes, and meter socket Enclosures... Not just meter main cabinets... I see a lot of panels with all the NM's just stuffed into a 2" PVC conduit....


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