AC raceway in basement....

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  #1  
Old 12-02-13, 09:09 AM
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AC raceway in basement....

Let me know if my preliminary ideas are sound.....

10/3 run to AC unit (30A breaker) in 1/2" EMT. Need to run out basment sill to an existing disconnect which has a knockout on the bottom. There is existing liquidtight between the disconnecte and the AC. Its about 100' from panel to outside on unfinished basement ceiling/joists. There is a 45' bend to the panel and another 45' bend to shoot out the basement in the area around the sill where the AC line set penetrates.


Instead of making bends with the emt, I was wondering if its OK to use flex metal for the 45 degree angles?

Before I need to go out basement sill I was thinking I need a junction box to connect the emt instead of the second 45 angle. There the emt would join with whatever material I should use to go outside with....

From there is liquidtight what I want to use to penetrate the house?

My mainconcern is that I wont be moving the disconnect so I am concerned how exact I would have to be with rigid metal coming out of the house.

Any thoughts.... thanks.
 
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Old 12-02-13, 09:13 AM
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Your unit may not require #10, check the minimum circuit ampacity on the nameplate.

AC units are straight 240 and only require 2 hots and a ground.

You should not need to run the cable in the conduit. If using conduit I would run individual conductors.

I would come into the back of the disconnect and just seal off the unused hole.
 
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Old 12-02-13, 10:07 AM
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10/3 run to AC unit (30A breaker) in 1/2" EMT.
Its about 100' from panel to outside on unfinished basement ceiling/joists.
Because of the length of the circuit, I'd agree with the #10 conductors. Are you using NM cable or individual conductors in the conduit. If NM cable, as pcboss stated, you do not need conduit. When you exit the basement, are you going into the back of the disconnect? Remember, NM cable cannot be used outside even in conduit. If you are using individual conductors in conduit, do not use flex at the 45 degree bends. You should either invest in a EMT bender or buy factory 45 degree elbows.
 
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Old 12-02-13, 10:22 AM
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10/3 individual conductors.

Can I use something flexible where it exits the house?

In order not to remove siding and the disconnect box I hoped to go out right next to the lineset and hopefully use liquidtight to into bottom of disconnect.
 
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Old 12-02-13, 10:40 AM
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10/3 individual conductors.

Can I use something flexible where it exits the house?

In order not to remove siding and the disconnect box I hoped to go out right next to the lineset and hopefully use liquidtight to into bottom of disconnect.
10/3 typically indicates a cable, but OK, you are using individual THHN/THWN conductors. In order to connect to the disconnect like you are wanting to, I think I'd install a 4" square 1900 box with blank cover inside the basement near the lineset and transition to sealtite to exit the house with the lineset and enter the disconnect. Use the U.L. Listed sealtite with the copper bonding strip.

https://www.platt.com/platt-electric...spx?zpid=16223
 
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Old 12-02-13, 05:19 PM
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You mention flex isnt a good idea for the bends.

The one I am concerned about is the 90 going down from celing into my panel. Its a traffic jam and I fear I have no choice but to use flex.

Is it against practice to connect flexible metal conduit with emt to bring the raceway down to the panel?
 
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Old 12-02-13, 06:13 PM
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With a proper fitting you can switch from EMT to flex.

Outside you can also use non-metallic liquid-tite conduit also. You just need to install a grounding conductor inside it.
 
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Old 12-02-13, 07:46 PM
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Is it against practice to connect flexible metal conduit with emt to bring the raceway down to the panel?
It's not a code violation if you don't mind it looking like the kid next door did it. I prefer a more professional looking installation.
 
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Old 12-02-13, 07:50 PM
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Most panels have knockout on the side you may be able to use if the top is too crowded.
 
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Old 12-03-13, 04:25 PM
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Go to Home Depot and buy a 1/2'' bender for $50, make your bends, sell like new bender to an electrical apprentice on kijiji for $40.
You mention a traffic jam, but the beauty of pipe is it can be manipulated to fit wherever you need it to. Investigate different bending techniques and see how you feel about it. As a 2nd year, I personally think it feels great to look at some sexy pipework you just finished after getting frustrated and swearing at the crappy space you're working with.
 
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Old 12-03-13, 07:14 PM
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Go to Home Depot and buy a 1/2'' bender for $50
I was about to say there is no way they cost that much, but when I checked I was just partially right.

Klein Tools 1/2 in. Aluminum Conduit Bender and Handle-56206 at The Home Depot

I was thinking more like $15 so I was wrong all the way around. Greenlee and Ideal benders are only about a buck cheaper.
 
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Old 12-04-13, 12:58 PM
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I really like my Gardner Bender foot benders with the built-in levels for 45[SUP]o[/SUP] and 90[SUP]o[/SUP]. I bought them to keep, of course, but I noticed that I can pick up a new 1/2" one for less than $25.

Gardner Bender 930B 1/2-Inch EMT Gardner Thinwall Aluminum Hand Bender at Amazon.com
 

Last edited by Nashkat1; 12-04-13 at 02:07 PM.
  #13  
Old 12-04-13, 02:17 PM
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The Gardner Bender EMT benders are what I was thinking off, but they don't come with a handle. Add the handles and you are back in the $30 range. I guess everything is just more expensive than I remember.
 
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Old 12-04-13, 04:36 PM
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You can just use a 1" galvanized pipe as the handle right?
 
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Old 12-04-13, 06:17 PM
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You can just use a 1" galvanized pipe as the handle right?
From memory, I believe they are 3/4".
 
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