The other day I saw an Edison employee high up in one of the steel towers washing off insulators with a hose. There's a 1" Galvanized water line that runs up the tower. He had his pump truck down below, and a short length of hose and nozzle up above.
These transmission lines are up in the hundreds of thousands of volts, and he's perched right on the grounded tower!

What enables him to do this without becoming an instant french fry?

Well, ya know how a bird sets on a wire, or a squirrel runs along one....

Honestly, I don't know how. Maybe the line was dead?

Uh, why would they wash insulators? Ain't that what rain is for?

Rain does not do an adequate job of cleaning the insulator.

What enables him to do this is the fact that water does not conduct electricity.

Tom

Is this water deionized or something?

distilled water is a very poor conductor, but knowing that i would still not be inspired to play hose tag with 100KV

they just don't make enough Coors...!

Rain does a pretty good job around here in the Midwest... of course it rains fairly often, and in more than sprinkles.

I've never seen insulators being washed, and I've seen utilities mowing treetops with helicopters, and maintaining the lines from a hydraulic boom suspended from that helicopter. What a ride.

Chemistry 101, water that does not have a ph of 7 will conduct electricity, a ph of 1 to 6.99 is acidic and 7.1-14 is basic, either side of the neutral point a 7.0 will conduct electricity. If distilled water is not at a ph of 7.0 it too will conduct electricity.

Distilled de-ionized water is what is used. On the West coast, fog moving in from the ocean will deposit a layer of salt on the insulators. When I lived on the central coast, at night I could usually see, and hear, some arcing on the insulators. PG&E usually used a large tanker truck & washed them from ground level, no PPE involved.

I'm not going to dig out my old chemistry books, but for water to be acidic or basic, wouldn't it have to have something in it that isn't water?

[This message has been edited by Tom (edited 09-02-2001).]

You should dig out the old chemistry book to make a blanket statement that water doesnt conduct elecctricity, is rediculous. AS I said if the ph is at 7 it will not conduct, going to either side of the neutral point causes it to conduct. Yes of course it would have to have something else in it, minerals appear quite naturally in nature aka hard water, or sulphur smelling water which we have a lot here in Ohio, acidic, tap water will conduct too. Even distilled water left out will become contaminated. As far as washing insulators I have never heard of it but we dont have rolling blackouts either.

It's done all the time here in the west.

Don't speak too soon. Deregulation is a cancer and it is spreading.

Deregulation is a cancer and it is spreading.

true, i see similarities to the oil snafu in the early 70's.

anyhow,
how is it these employee's are convinced that there would not be a stray ion or two??
that's gotta be one good sales pitch !

maybe they should just wait for the rolling blackout???


[This message has been edited by sparky (edited 09-02-2001).]

bordew,
We are not chemists, but electricians. We need to be able to ask questions or respond to others without being accused of making "ridiculous" remarks. I am here to find information by asking questions, and hope to be able to continue to do so without worrying what others might think.

I realize that when most of us say water, we mean water and whatever is in it, such as chlorine, flouride & any other trace element that may come with it as delivered from the tap.

I purposely did not explain my statement just to see if I could get a rise from someone.

I'll stick with my original statement, water does not conduct electricity. The compound "water" is made up of 2 atoms of Hydrogen and one atom of Oxygen. Some of the impurities that can be found dissolved or suspended in what most of us call water will conduct electricity, but the water won't.

Good stick with your original statment.

Well let me put it this way, if someone gets electrocuted because they believe that water doesnt conduct electricity, what would you call it ? Would you work on a panel hot standing ankle deep in water ? I hope not.

Tom,

Thanks for the explanation of why Insulators might have to be washed. If Seawater is the culprit that explains why someone inland would not see it done. I wonder if they do it on the East Coast.

I remember from School that pure H2O is actually a great insulator but should not be confused with the "Water" we all know on a daily basis.

Bordew,

Does a Balanced PH always mean that it is a poor conductor of Electricity? I mean, if something is added to water to balance the PH the impurities are still there (Right?)Does the balance itself make the water a poor conductor?

Bill

I live right on the east coast of England, and in winter the salty spray and atmosphere from the North Sea gets everywhere. I've never seen insulators being washed though, and I've lived here 4 yrs.

I've also been led to believe that 100% pure deionized water is a very poor conductor, although my chemistry is so rusty that I couldn't start to figure out why without reading a few books.

Anyway, whatever the chemistry says, I'd be far too much of a coward to want to play chicken with 11kV+.

Just to prove again to myself, I took glass and a temp-light pigtail and tapped one lead into a large glass, then one lead from an old extension cord, the two were separated by about 3 inches of air, then I added water until the leads were covered almost instantly the bulb got a very faint glow, this is tap water, then I added some baking soda and of course the bulb got much brighter. after all that I turned it off and tasted it there was no discernable taste of baking soda.
My point was this, this board is accessable by anyone, and would hate to see someone get hurt by believing that water does not conduct electricity.
For example I was making the final connections to a service to Ohio Edisons conductors, Hot of course, this was a few years ago and it was in early November, and I was standing on a ladder orange insulated fiberglass,and it started to sleet you know freezing rain the ladder soon got coated and my gloves wet, this was before I got the rubber ones with the leather protector,and to finish up the last tap I was getting zapped real good.
WAter by itself with a Ph of 7 will not conduct, whether it be minerals or whatever is in the water it will conduct, abeit a medium the current will flow through it. Even distilled water left out will contaminate just the nature of the beast.

Bill, they do do it inland too. I am 70 to 100 miles from the coast and I see SCE trucks washing insulators every so often. I imagine the nasty smoggy air is a contributor to insulator tracking.
Oh, one more thing. Transmission towers (out here at least) are not grounded in the way that we all think of it. They have static ground wires that run up high on the towers but if you look they are insulated from the tower. The towers themselves have some coiled copper in there footings but there is no bonding done from tower to tower. Granted at these voltages the earth can be a pretty good return though.

The "sea air" is a good call. These are the trans lines coming from Huntington Beach generating station, about 1/8 mi from ocean. BTW,like Nick said, all of our insulators are washed periodically, but this is the 1st time I've seen somebody do it like this. Was kind of like watching the "Flying Wallendas" for free.


[This message has been edited by electure (edited 09-03-2001).]

I'd hate to see someone hurt too. A qualified person is supposed to be aware of all the hazards. I would think that a qualified person would normally expect "water" as we normally find it is a conductor. Unqualified persons should keep their hands in their pockets.

Water being a non-conductor is a factual statement. You just have to watch out for the exceptions. Just like the NEC.