Running wire through PVC conduit outdoors


  #1  
Old 10-07-22, 05:38 PM
C
Member
Thread Starter
Join Date: Aug 2022
Posts: 27
Likes: 0
Received 1 Like on 1 Post
Running wire through PVC conduit outdoors

I have an existing outdoor ceiling box that I would like to branch off to a new box (for a floodlight) approximately 4 away. Both boxes have 1/2 threaded holes. Can I run 3-wire sheathed cable through 1/2 PVC conduit or must I run separate wires only? Does the sheathed cable and the conduit diameter cause an overheating concern? Thanks in advance!
 
  #2  
Old 10-07-22, 06:37 PM
L
Member
Join Date: Nov 2015
Posts: 1,814
Received 177 Likes on 152 Posts
You can run sheathed cable, however, you cannot run NM-b (aka Romex) outside even if it is in conduit.
You can use UF-b cable or THWN wires instead. You can buy THWN by foot at hardware stores, so it probably is easiest.
 
  #3  
Old 10-07-22, 07:25 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 71,630
Received 3,323 Likes on 2,984 Posts
Conduit between the two boxes will probably look the neatest.
You'd need to run three separate wires (THWN-THHN) or you could use 14-2 w/gr UF cable.
You could also use just 14-2 w/gr UF and no conduit.
Either way would be acceptable.
 
  #4  
Old 10-08-22, 05:24 AM
C
Member
Thread Starter
Join Date: Aug 2022
Posts: 27
Likes: 0
Received 1 Like on 1 Post
Thank you PJmax and lambition! The electrical boxes are mounted to steel plates which are mounted to the underside of a corrugated steel concrete pan between two "legs" of the pan (second story balcony installing lights and ceiling fan on the underside). The span between the two boxes is approximately 4' in the same channel of the steel corrugated pan. Can I install 4' of outdoor PVC conduit without having to secure it to the ceiling? In other words, connected to the two electrical boxes but not anchored. With my electrical boxes I can use either 3/4 or 1/2 PVC, should rigidity matter. I thought I read somewhere that suspended PVC requires anchoring every 3', is this correct?
 
  #5  
Old 10-08-22, 03:16 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 71,630
Received 3,323 Likes on 2,984 Posts
PVC would droop in the middle if not fastened.
You could use metal EMT.
Easy to work with and looks nicer than PVC. (also paintable).
Comes in 10' length. You'd need two EMT connectors.
1/2" EMT compression connectors
10' 1/2" EMT
 
  #6  
Old 10-09-22, 04:38 AM
C
Member
Thread Starter
Join Date: Aug 2022
Posts: 27
Likes: 0
Received 1 Like on 1 Post
Thank you! I will go with EMT.
 
  #7  
Old 10-09-22, 07:47 PM
L
Member
Join Date: Nov 2015
Posts: 1,814
Received 177 Likes on 152 Posts
Don't forget that you will have to bond EMT to ground as well.
Easiest way accomplish this is using metal junction box and bond this box, which you may already have.
 
 

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