water in conduit quick help needed!

Reply

  #1  
Old 01-25-16, 02:03 PM
Member
Thread Starter
Join Date: Oct 2013
Posts: 592
water in conduit quick help needed!

Long story short.

I found some water (condensation) dripping from a metal conduit in a ceiling box. The conduit ran exposed in the unheated attic over to a wall and down to an outlet.

I insulated the conduit in the attic. I am going to use duct seal on the conduit ends once it dries up. But there is still a bit of moisture dripping some 4 hours after finding this.

I have no lights because I cant reinstall the fixture yet and the box is opened up and exposed to warm interior air even more (which by the way is 45 RH).


If I plug the hole with duct seal and reinstall the fixture will any other remaining moisture evaporate or am I doing something stupid by doing this? How should I proceed?

and in general I am confused why this has occurred? I am sure its coming from INSIDE the conduit. There is no roof leak nor water pipes in the vicinity. It has to be condensation but I never figured it would be enough to notice a leak!!
 
Sponsored Links
  #2  
Old 01-25-16, 02:07 PM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,506
I'd shop vac out the moisture that is in there as best I could, then plug both ends well with duct seal. You're not really going to get much better than that.
 
  #3  
Old 01-25-16, 02:17 PM
Member
Thread Starter
Join Date: Oct 2013
Posts: 592
I just tried that again. Would you plug it even if it still seems wet?

If I leave it over night to dry, wont it just be worse since now the box is exposed to the room and I haven't plugged the pipe yet?
 
  #4  
Old 01-25-16, 02:31 PM
Member
Join Date: May 2015
Location: USA
Posts: 3,138
You could try the shop vac at one end while aiming a hair dryer at the other end to provide warm, dry air. let it run as long as you can stand it and then seal up the ends. If you have a multimeter, you can check for resistance from the wires to the conduit; should be open circuit.
 
  #5  
Old 01-25-16, 02:32 PM
Member
Join Date: Oct 2015
Location: usa
Posts: 665
For a first cut, I would do the following:
1-At the lowest point of the horizontal run of the conduit in the attic, drill a i/8 inch hole in the bottom of the conduit (be careful not to drill into the enclosed wires and make sure the circuit breaker/fuse is off before drilling). This will prevent condensation in the horizontal run of the conduit reaching a level to run down to the outlet and hopefully drain before going down to the ceiling light.
2-Spray fireproof foam in the outlet box where the conduit terminates and any cables that enter/exit that is allowing moist air to get into the conduit going to the attic.
As a second cut, consider replacing the wires and the conduit with romex.
Good luck
 
  #6  
Old 01-25-16, 02:36 PM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,506
Yes I would seal it up as-is. It's not going to dry completely until summer anyway, but if it's sealed up it will eventually dry. You just need to stop active air flow to prevent the humidity from condensing.
 
  #7  
Old 01-25-16, 04:44 PM
Member
Thread Starter
Join Date: Oct 2013
Posts: 592
I realized the said conduit was feeding an unused outlet that I could abandon, so I pulled the wire out it! They were soaked! I think I was seeing the moisture running down the wet insulation rather than the pipe itself. So everything is dry now without wires in the conduit. Most of the insulation was stained with rust too.


However, im still perplexed! Could condensation really cause pooling or filling of a conduit? Or enough to soak the length of the wire?
 
  #8  
Old 01-25-16, 05:26 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 46,120
However, im still perplexed! Could condensation really cause pooling or filling of a conduit? Or enough to soak the length of the wire?
Sure....a nice supply of warm humid air, if allowed, would keep condensing forever.
 
  #9  
Old 01-25-16, 06:49 PM
Member
Thread Starter
Join Date: Oct 2013
Posts: 592
So I rolled out a piece of R30 on top of most of the conduit in the attic. I stuffed insulation around the box too from the attic as well.

Inside I sealed the holes of the pipe with ductseal. Theres no wiring anymore in the pipe but its still connected to the box... (with other wiring of course).

Do you think that will keep the moisture away?

The only thing I feared sealing the entry holes with ductseal was if the moisture still happens it will be building up in the conduit. But what I did was code compliant NEC 300.7... so I assume that's the proper fix?
 
  #10  
Old 01-26-16, 08:14 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,506
Ever been through winter in a house with aluminum windows? They're wet all winter no matter what you do. Warm humid air meets cold metal equals condensation no matter what. The best you can do is to allow as little humid inside air as possible to escape into the attic. Duct seal is the best material to do that inside conduit, great stuff foam or caulk is the best product to use on any other gaps between the living space and unconditioned space. If you can access the tops of the electrical boxes penetrating into the attic space, go ahead and blast them with great stuff to build up a layer of foam over the whole box.
 
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