Is My Conduit Leaking?

robertc65

I have a length of 2" conduit running underground from my house to my Shed. Currently inside the conduit are (4) 4 gauge THHN runs, a 12-3 run and a handy dandy pull string. (Thank you previous uber handy man home owner for the string). I've been inside the junction box just inside the basement a few times and always noticed it was very musty. Also the ground wire on the 12-3 run is green from moisture. The other wire look just fine. In the process of pulling a length of 12-3 though this morning, using the included pull string, I found the string to be soaking wet and real musty smelling. This is bad right? I don't see any water in the junction box at all, and it's bone dry. Has my conduit been compromised or could this be from condensation? The conduit appears to be about 2 1/2 feet deep if that matters at all. Am I digging a new trench this weekend or what? I took off work today for this project, so for now it's on hold. I think I'll order a pizza and find some other way to get dirty today.

Thanks in Advance

Rob

SmithBuilt

Is the wire THWN for wet use?

To my knowledge all THHN produced today is also THWN.

robertc65

Yes it also sports the THWN, AWN and MTW labels. I guess that means I'm OK with the current runs, but does it sound like I have a leak or is some amount of moisture and musty smell to be expected?

Thanks

Rob

jbfan

You will always have water in underground conduit. My concern is why are you pulling a 12/3 in there and is it uf cable?

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mickeyco

Do you have drain holes in the bottom side of the conduit and if you do are they plugged? As far as the musty smell a good cleaning of the wires and conduit every few weeks and a deodorant should help.

robertc65

I installed some flood lights on the shed and I want to be able to turn them on and off from inside the kitchen. I was planning to run a length 12/3 UF simply because, I happen to have it left over from a previous project. It looks like there is plenty of room pipe to accomodate the additional 12/3. I know I should be running THHN, THWN inside of conduit, but on my own house is it really an issue to run romex. It does not appear that the conduit will be over stuffed. I don't forsee me ever running more than a few power tools and lights in the shed. The previous homeowner ran this 50AMP circuit to the shed, so he could use his arc welder out there.

I don't know myself so I'm asking. Should I just go buy THHN or am I oK in this instance with the 12/3 UF. Damm copper prices

robertc65

I don't know. Let me dig it up and look. Am I supposed to have drain holes? I thought the idea was to have it water tight.

I'll spray some Lysol in there for the Musty odor.

SmithBuilt

I think your ok.

The only concern with uf in the conduit is conduit fill and it sounds like your ok on that too.

mdshunk

All underground conduits have water in them. If not from subsoil water infiltration, it's from condensation. All conduits that pass from warm areas to cool areas are to be sealed to prevent (lessen) this condensation. All conduits are to be arranged to drain, in some manner.

Magnettica

I agree, all conduits eventually get water in them. I'm thinking if the 2" conduit is buried 30" deep then whoever originally installed it did a helluva job. As far as the ground wire turning green, that's normal for copper wire, and copper in general (saw that on the History Channel )

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BoydS

I'd like to add something to this discussion and address your questions.

1) You found the pull string to be wet and musty smelling (this is bad right..?). No is not bad. As mentioned before all underground conduit systems will contain some moisture (very common). That is one of the reasons you need to use wire rated for wet locations (underground conduits systems are a wet location).

2. No water in the junction box. Last time I remember, gavity has something to do with this.

3. Has my conduit been compromised or could this be from condensation. No it has not, as long as the conduit run from the house to the shed and it is a completely closed system it is common for condensate to build up in the conduit.

4. The conduit appears to be about 2 1/2 feet deep if that matters at all. The conduit is at an excellant depth. Good for the previous homeower to provide that for you. Very good protection.

5. Am I digging a new trench this weekend or what? No reason to do that at all.

As for as the other issues that have been addressed you mentioned that you have left over 12/3 UF cable. I will say that I have not done a conduit fill calc., but I would believe that you would have no problem pulling that through the 2" conduit (which you have already done). I see no issue with the UF pulled throuh the conduit.

Someone mentioned: "Do you have drain holes in the bottom side of the conduit and if you do are they plugged?" Electrical underground conduits do not have holes in them. They are completely a closed system.

Another thing that was mentioned was, All conduits are to be arranged to drain, in some manner. This is true, but as for as I know you cannot drain a conduit that is underground. You can drain vertical runs of conduit at a low point before in goes in the ground, but in the ground thats new to me.

As for the smell, that's up to you how you wanna handle that.

Just my 2 cents........

robertc65

Thanks for the info MD. I understand now that the conduit will have some water inside. Based on what you say above my conduit should be sealed, but have a drain of some sort. Is this kind of like the drain you would have for a sprinker system? A plug or valve at the lowest point to allow for drainage. If mine has a drain, It would have to be burried. If not, based on the grade it would drain into the junction box in my basement as this is the low point in the run. On the good side, so far I see no sign of water having been in this box.

robertc65

Thanks a whole lot BoydS for all of your comments. I have a much better understanding now.

robertc65

This summer I plan to run some conduit for low voltage lighting, security cameras, and other misc low voltage sensors and such. I assume all of this wire will have to be rated for wet locations. I have seen direct burial CAT5 and Coax, but I have not seen direct burial 22 gauge multiconductor cable. Also since I'll be using conduit and not just laying my cable in a trench, is there a less expensive option for CAT5 and COAX that is wet rated but not direct burial.

Thanks in Advance

Rob

GregS

Yes. Even home depot has boxes of 'indoor/outdoor' cat5e cable. Costs a bunch more, but suitable for outdoor use.. meaning will not dry up due to UV, or brittle jacket from cold, water from rain/snow, etc..

I've used it for short runs from a demarc to inside a house.

Even Bell here uses just standard 22g quad for doing temp runs around new construction houses in the winter. Of course it will get a a shovel through it before it will fail from deterioration..