12-3/G inside in Plastic Conduit

Reply

  #1  
Old 07-13-14, 06:51 AM
Member
Thread Starter
Join Date: Jul 2014
Posts: 35
Received 0 Votes on 0 Posts
12-3/G inside in Plastic Conduit

Hello, is it within code or against common sense to run inside romex in waterproof gray conduit that will exit the house. Specifically, we are installing a mini split and the wiring needs to run along the eaves and down the side of the house approx 25ft. There is a 4 inch slim line trunking on the house for the mini split line set and the gray conduit will be inside the trunking and of course the romex inside the conduit. That side of the house faces the south and it is very sunny. Will the romex get too hot and not be able to cool? Should I look at a different electrical supply line such as UF or THH? Thanks
 
Sponsored Links
  #2  
Old 07-13-14, 07:25 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,967
Received 59 Votes on 52 Posts
Welcome to the forums!

Normal Romex (NM-b) can not be used outside, even if it is installed in conduit and even if it is inside the "line hide" trunking. If it is inside the trunking with the lineset you should be able to use 12/3 UF as long as it is protected.

Otherwise your next best option is to use conduit and THWN wires. I would recommend installing liquidtight flexible metal conduit. The liquidtight flexible non-metallic conduit is very difficult to install wires in so I would avoid that if possible.
 
  #3  
Old 07-13-14, 09:24 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,946
Received 31 Votes on 27 Posts
If the unit is straight 240 you only need xx-2 cable, not xx-3. The ground does not count in cables. It is counted in flex cord.
 
  #4  
Old 07-13-14, 09:50 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,967
Received 59 Votes on 52 Posts
Note: Some of the mini splits I have wired require 3 conductors plus a ground between the inside unit and outside unit. PC's advice might be correct so be sure to look at the requirements of your unit(s)
 
  #5  
Old 07-13-14, 12:03 PM
Member
Thread Starter
Join Date: Jul 2014
Posts: 35
Received 0 Votes on 0 Posts
Thanks for the response, on the way to church I picked up UF-8 12-3. The metal flexible conduit they had was not recommended for outside. I did not see any exterior only metal flexible duct at Lowes, but they did have the gray conduit in 3/4. I will check again to see if it will fit with a fish tape/soap ....thanks
 
  #6  
Old 07-13-14, 03:50 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,967
Received 59 Votes on 52 Posts
I'm sure Lowes will have it. This is what you want: Shop Southwire Metal Liquid-Tight 50-ft Conduit (Common: 1/2-in; Actual: .5-in) at Lowes.com

Also remember with conduit you can only have 360 degrees of bends and the raceway should be complete before pulling in wire. I recommend either UF or LFMC. not both. UF will be very difficult to install in conduit.
 
  #7  
Old 07-13-14, 06:38 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,946
Received 31 Votes on 27 Posts
You can typically buy a whip already made in the box box stores for AC units.
 
  #8  
Old 07-13-14, 07:54 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,967
Received 59 Votes on 52 Posts
I have never seen a 25' pre-assembled whip.
 
  #9  
Old 07-13-14, 09:11 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,493
Received 33 Votes on 25 Posts
Don't need a 25 foot whip, just one long enough to reach from the local disconnect to the condensing unit. Use rigid PVC conduit with individual conductors to the disconnect from the source. Don't forget that you also need a 120 volt, 20 ampere receptacle within 25 feet of the condensing unit for servicing.
 
  #10  
Old 07-14-14, 11:04 AM
Member
Thread Starter
Join Date: Jul 2014
Posts: 35
Received 0 Votes on 0 Posts
Done, UF in Metal Liquid-Tight conduit. Had to bump up to 3/4" conduit for more space for UF, installed wire in conduit first (slowly) then laid inside slim line duct. Had a 90 into house, so used a liquid tight 3/4" elbow on slim line (secured to back of duct well), then chalked around vinyl siding. Old house wrapped in 1x12's with exactly 2x4 old oak studs. Believe I will place a small piece of conduit in the hole of 1x12's and wall cavity. Many thanks to all responding. Good Tip: Metal Liquid-Tight 50-ft Conduit (Common: 1/2-in; Actual: .5-in) at Lowes.com
 

Last edited by sparkyweld; 07-14-14 at 11:06 AM. Reason: correct content
  #11  
Old 07-14-14, 07:57 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,967
Received 59 Votes on 52 Posts
Just an FYI, I posted 1/2' because you could have ran THWN wires in the conduit instead of the UF as I mentioned earlier. But, Glad you got it done and it all worked out for you!

For the others reading this, or not reading as the case might be , The OP was running the interconnect wires between the outside unit and inside unit of a mini split system. This is why the run was 25', and needed to be 12/3 with ground cable. Yes, a standard A/C disconnect and 6' whip will work fine to feed the condensing unit, but you still have to interconnect the two units.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: