Does an 8 gauge wire require fire resistant conduit?

Reply

  #1  
Old 12-05-16, 12:36 PM
C
Member
Thread Starter
Join Date: Jul 2010
Location: USA
Posts: 959
Received 0 Votes on 0 Posts
Does an 8 gauge wire require fire resistant conduit?

I need to wire a 240v to my heater in the garage. Do I need to put this 8 gauge electrical wire inside a fire resistant conduit? If there are rooms, between my drop ceiling and the joist, do I need to drill roles in the joist for this wiring?
 
  #2  
Old 12-05-16, 12:44 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,583
Received 13 Votes on 11 Posts
If you mean individual wires they must always be run in conduit. Any conduit used meets residential fire rating requirements. If allowed by local code you could just use cable and no conduit required except for sleeves where the cable might be exposed to damage. If you run cable it can be fastened to running boards or run through holes in the ceiling joists.

What is the amp rating of your heater?
 
  #3  
Old 12-05-16, 12:46 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,213
Received 103 Votes on 89 Posts
Above a drop ceiling I would just use running boards.
 
  #4  
Old 12-05-16, 01:03 PM
C
Member
Thread Starter
Join Date: Jul 2010
Location: USA
Posts: 959
Received 0 Votes on 0 Posts
If you mean individual wires they must always be run in conduit. Any conduit used meets residential fire rating requirements. If allowed by local code you could just use cable and no conduit required except for sleeves where the cable might be exposed to damage. If you run cable it can be fastened to running boards or run through holes in the ceiling joists.

What is the amp rating of your heater?
I was thinking about this wire from Amazon or local store.

I assumed I need to run two wires, hot and neutral, correct?

And the heater I have is 240v with 2500w-5000w but it didn't mention about amps...unless I didn't see it.
 
  #5  
Old 12-05-16, 01:09 PM
C
Member
Thread Starter
Join Date: Jul 2010
Location: USA
Posts: 959
Received 0 Votes on 0 Posts
Above a drop ceiling I would just use running boards.
I found this little diagram. I was wondering if it is legit.
 
  #6  
Old 12-05-16, 01:32 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,213
Received 103 Votes on 89 Posts
A 240 volt heater does not use a neutral. It uses two hots and a ground.
 
  #7  
Old 12-05-16, 01:35 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,583
Received 13 Votes on 11 Posts
The wire linked is for boats not houses. Use NM-b cable or THHN/THWN individual wires in conduit.
 
  #8  
Old 12-05-16, 01:46 PM
C
Member
Thread Starter
Join Date: Jul 2010
Location: USA
Posts: 959
Received 0 Votes on 0 Posts
The wire linked is for boats not houses. Use NM-b cable or THHN/THWN individual wires in conduit.
I see. Would something like this one work? I'm basically going to try to wire the house and perhaps call professional electrician to do the actual wiring with the breaker.
 
  #9  
Old 12-05-16, 01:50 PM
C
Member
Thread Starter
Join Date: Jul 2010
Location: USA
Posts: 959
Received 0 Votes on 0 Posts
Another question I have is, what's the best way to estimate how long I will need?
 
  #10  
Old 12-05-16, 03:00 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,583
Received 13 Votes on 11 Posts
That is cable and would be okay. You would not use conduit. Again how many amps is the heater? You may not need #8.
 
  #11  
Old 12-05-16, 03:17 PM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,943
Received 44 Votes on 42 Posts
Most 240V heaters do not require a neutral wire, so the #8-2 NM cable you linked would be OK. That cable is good as long as the run is indoors and above ground. The cable needs to be fastened to framing and protected from damage, but this is easily accomplished with standard building materials. You can bore holes and run it through the joists or you can fasten it to a 2x4 running board nailed onto the joists. If it runs down the walls in the garage it should run along a 2x4 or through a piece of conduit for protection from crush/cut.

For distance estimation, take your tape measure and measure each leg of the planned route including up and down walls where necessary then add about 10 feet. You can very easily make it shorter, longer is a little tougher.
 
  #12  
Old 12-05-16, 07:32 PM
Z
Forum Topic Moderator
Join Date: Sep 2005
Location: USA
Posts: 5,539
Received 153 Votes on 136 Posts
As the OP stated:
And the heater I have is 240v with 2500w-5000w
That's about 21A (5000w / 240v) at the high setting. Code requires constant loads like heat on a circuit that's loaded to a max of 80%. So you could use a 30A circuit to run this heater.

You'll want to use a 30A double pole breaker with 10/2 (with ground) cable.
 
  #13  
Old 12-05-16, 10:44 PM
Join Date: Dec 2016
Location: Puerto Rico
Posts: 38
Received 0 Votes on 0 Posts
If he uses a Romex NM-B cable 10/2 with ground does the white wire will need to be taped, marked with red electrical tape at both ends because it will be used as a hot wire instead of as a neutral, right?
 
  #14  
Old 12-05-16, 11:25 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,583
Received 13 Votes on 11 Posts
Actually Joe the white can be remarked any color except gray or green even black.
 
  #15  
Old 12-27-16, 10:53 AM
C
Member
Thread Starter
Join Date: Jul 2010
Location: USA
Posts: 959
Received 0 Votes on 0 Posts
This cable has four wires. The black is hot, the white is neutral, the gold or gray is ground, what is the red wire?
 
  #16  
Old 12-27-16, 10:59 AM
C
Member
Thread Starter
Join Date: Jul 2010
Location: USA
Posts: 959
Received 0 Votes on 0 Posts
Looks like I just found the answer in this article.
 
  #17  
Old 12-27-16, 11:48 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,213
Received 103 Votes on 89 Posts
There is no need to spend extra money for the third conductor that is not needed. The white in a 2 conductor cable can be identified with tape or magic marker as a hot.
 

Last edited by Tolyn Ironhand; 12-27-16 at 07:06 PM. Reason: corrected auto corrected typo
  #18  
Old 12-28-16, 07:16 AM
P
Member
Join Date: Feb 2016
Location: United States, Virginia
Posts: 1,504
Received 123 Votes on 97 Posts
This cable has four wires. The black is hot, the white is neutral, the gold or gray is ground, what is the red wire?
The cable pictured is wrong for the description that is given. The picture is 8/3, not 8/2.
 
  #19  
Old 12-28-16, 11:07 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,583
Received 13 Votes on 11 Posts
From your link:
14 gauge Romex is still used in some applications and is rated for 15 Amps and is grey jacketed.
It is used in most not some applications. It is white not gray.

From your link:
For our cabin, we used 12 gauge Romex for all of the outlets and lighting circuits.
Over kill. Not normally needed for lighting or most general purpose receptacles.
This is very common now-a-days rather than running 14 gauge.
Not true. Statements obviously brand him as a novice whose statements are not to be relied on.
 
 

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