Can water wick thru a conductor??

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gap

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Gainesville Florida
Hello all,
We have an 800A panel fed from pole mounted transformers. The panel is inside an electrical room and the pole is outside about 75' away. The service conduit, and wires, travel down the side of the pole, underground, and pops up thru the slab into the panel. No changes have been made to the panel in several years. The pole itself was replaced about 4 months ago. Last week we had a breaker go bad in the panel, and the labels on the front of the breaker looked like they had been wet. No sign of water anywhere inside the panel. Last night we had a bad rain storm and I looked inside the panel this morning and found water drops dripping off the strands of the neutral wires where they are landed on the bus bar. The outside of the insulation of these wires is dry, as is everything else in the panel--except the breaker which the water was dripping on. There is no other connection in the neutral between the bus bar and the transformers on the pole. The only thing I can think is that water is entering the wire stranding where they are attached on the pole, then wicking down, seeking its own level, and being pushed out the other end in our panel? I've never heard of this, but I can't think of what else may be happening. Any ideas?
Regards,
Scott
 
Re: Can water wick thru a conductor??

I think you have the correct explanation. But I don't know what to suggest to correct the problem.
 
Re: Can water wick thru a conductor??

What's the orientation of the poletop end of the neutral? . . .Or the rest of the service conductors?

If the conductors are ending going straight up, is there a possibility of putting the end in the bottom of a drip loop?
 
Re: Can water wick thru a conductor??

All the conductors are terminated going straight up--into exposed terminals on the xformers, then hang down to a 1'+ drip loop before entering the weatherheads. There is no water coming out of the phase wires, just the neutrals. A high voltage crew just left, at first they scratched their heads, then put a tube of silcone over each neutral connection point on the xformer? Looks like rain soon so I guess we'll see.
Scott
 
Re: Can water wick thru a conductor??

This is interesting. Probably a small point but it doesn't sound like wicking. One end of the coductor is higher than the other and the water is being forced out.

I'm just kind of curious. This doesn't seem like a very common problem but at the same time I'm a little surpised it doesn't happen more often.

What kind of condition are the conductors in? Are they unusual at all?

And I thought the power company is supposed to ensure this doesn't happen. Exposed transformer terminals? That doesn't sound right to me. Silicone? That doesn't sound right to me either. Hacks use silicone.

I'm out of my element with 800 amp and municipal type stuff, like I said, I'm just curious.
 
Re: Can water wick thru a conductor??

Originally posted by physis:
a small point but it doesn't sound like wicking. One end of the conductor is higher than the other and the water is being forced out.
Click to expand...
Very true, sharp observation. :cool:

Originally posted by physis:
Exposed transformer terminals? That doesn't sound right to me.
Click to expand...
I have never seen a pole mount transformer with anything but exposed terminals.
 
Re: Can water wick thru a conductor??

About 15 years ago, I was disconnecting some 5 kv unshielded cable in some switchgear. The connection to the bus was tightly taped. The conductors originated at an outside exposed bus connection with the terminations vertical. The conductor was about 75' long with a 20' vertical section and were 500kcmil. When I got most of the tape off, they started dripping water. On the next one we placed a bucket under the termination to catch the water and about a quart drained out. When we replaced the conductors, we used a special compression lug that had a skirt that extended over the conductor insulation to prevent this from happening again.
Don
 
Re: Can water wick thru a conductor??

I don't look that close but around here I see spliced conductors with drip loops.

Edit: Alright Bob, I have to go do some work, and I'm gonna be looking for these "exposed terminals" :confused:

[ April 08, 2005, 03:21 PM: Message edited by: physis ]
 
Re: Can water wick thru a conductor??

I agree that the silicone caulk is a temporary fix at best.

Sweet talk or cajole the PoCo into adding their own conductors from the xfmr terminals down to the bottom of the drip loop. There, splice their conductors to your conductors. The covers they'll place over those splices should be loose enough to not hold a pool of water over the end of the conductor sheath.
 
Re: Can water wick thru a conductor??

Don-seems like you've encountered this before I guess it can happen. If the silicone (hack--yes...but the storm clouds are rolling in again...) doesn't work our next step is to have a shutdown and install the crimp-on, closed end lugs and use heatshrink around it. I've never seen the kind with the skirt you mentioned. Any idea who makes them?
The conductors are in decent shape and we're installed in '89. For the record, the pole connections are approx. 30' above grade and the neutral lugs in the panel are 5' above grade, maybe 115-120' of wire, two conduits--a neutral in each (both neutrals dripping). I'm still having a hard time believing this, and so is the high voltage crew that checked the pole. Why am I not getting rich changing out wet breakers in the zillions of other similar installations out there?
Scott
 
Re: Can water wick thru a conductor??

Here's another hack.

Compromise the integrity of the insulation of each conductor at the very bottom of each drip loop. Skin open a small divit on the underside of each conductor, just big enough to let in air and let out the water coming down from the xfmr terminals.

I ask this community of minds, is there a NEC citation that would clearly prohibit this?
 
Re: Can water wick thru a conductor??

I'm not gonna look for it Al, but damaging the insulation?

I did take a look at utility transformers and found that every one I saw had exposed terminals. I guess I really don't pay much attention to those.

I also saw that some are terminated upward and some are terminated downward.

This is an uneducated guess, but I'm thinking that most of the time the conductor strands and insulation are formed so tightly together that it would take quite a bit of weight from a water column (that's hard to get with no room for water) to squeeze through. But once a path is open, forget about it. It's a hose now.
 
Re: Can water wick thru a conductor??

I think the correct term might be "siphon" ...

The water travels inside the conductor insulation. Properly set drip loops with water stop style butt splice connections should correct the problem.

shortcircuit2
 
Re: Can water wick thru a conductor??

If the power company brought the riser conductors right to the transformer terminals no amount of drip loop will cure the problem.

The water will pass through the loop just like water through a plumbing trap.

The only way to stop this would be as Don suggested using a terminal with a skirt.
 
Re: Can water wick thru a conductor??

If the drip loop goes up before it goes down again the water can't be forced through the conductor. Not syphon either.

A "P trap" has an entrance above the P trap. Pressure exists because the p trap is lower than the entrance.

I like Al's original solution. Turn the stupid conductors upward.
 
Re: Can water wick thru a conductor??

Originally posted by physis:
If the drip loop goes up before it goes down again the water can't be forced through the conductor.
Click to expand...
Your not going to get the power company to face the terminals up so that the loop is higher than the entrance.

By the way a siphon can work up hill about 14'. ;) as long as the downhill portion is longer than the up hill portion.
 
Re: Can water wick thru a conductor??

Bob, don't make me get into the weight of water columns and displacement. Because we'll all regret it.

But like I said, when I was out earlier, I saw about 50% of the transformer terminations with conductors attatched from above the terminal. Sure is a better idea than silicone.
 
Re: Can water wick thru a conductor??

Scott,
I don't remember who made the lugs. I did a quick search and didn't find them.
Don
 
Re: Can water wick thru a conductor??

Originally posted by physis:
Bob, don't make me get into the weight of water columns and displacement. Because we'll all regret it.
Click to expand...
Would we regret it as much as switching dinning room outlets? :) , never seen it done in this area. :(
 
Re: Can water wick thru a conductor??

Hey, I just live here. They don't allow any of us to make any decisions. :D

Edit: That reminds me Bob, did you notice that someone has allowed you a free pass to add another post in that thread without having to accept responsibility for it? :D

Additional Edit: Doesn't that thread hold the title for the most regretable thread ever? :D :D

[ April 08, 2005, 08:29 PM: Message edited by: physis ]
 
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