Thursday, May 12, 2016

What artists need to know about utility poles

Commonly called "telephone poles," utility poles carry a lot more than just phone service. 

They also conduct electrical power, street lights, internet, cable TV, signs, surveillance cameras, traffic signals, pedestrian signals, and seasonal decorations. 

Anatomy of a Utility Pole
Things to Look for:
• Functions are stratified by height, like life in a rain forest. Electric power at the highest voltage is carried on the top. In the USA, there are typically three uninsulated aluminum wires (each about 1/2 inch thick) spaced across the top crossbar, held up with three insulators. 

• For every few houses or businesses, there's a set of transformers—three big cylinders. These lower the voltage from the Primary Distribution Zone to the Secondary Distribution Zone below. Inside the transformer typically there's a coil of copper wire wrapped around a steel core, all bathed in oil. These generally don't explode in storms; there's a cigar-sized fuse that's designed to blow.

• Secondary distribution lines are also in threes just below the transformer level. The primary and secondary zones together comprise the "supply space."

• Street lights, yard lights, and traffic signals are wired to the Secondary Zone. Sodium vapor street lights are rapidly being replaced by LED lights, changing the color of the urban night from yellow to cool white.

• The twisted wires running off to buildings from below the transformers carry electrical power. Commercial businesses with high energy demands require thicker bundles. 

• The Communications Zone is the bottom level. It includes both fiber optic and coaxial cables with junction boxes and repeaters. These are usually the thickest cables. They serve internet, cable TV, police and fire alarm systems, and telephone. 

• There's normally more space between the Secondary and Communication zones than there is in the pole I drew at the top of this post. This space is called the the "Safety Zone," and its purpose is to protect telecom workers from high voltages.

• Telephone cables often can't support their own weight, so they hang from, or are lashed to, a thinner, uninsulated support strand, and they droop below that strand for stretches. There are various methods (such as loops) used to relieve stress or to store excess cable. Fiber optic cables sometimes have U-turns to store a longer section of cable without cutting it or breaking it.

• Horizontal rectangular boxes are junction boxes or splice boxes, giving access to the telephone connections. They also hang from the support strand.

• You'll see thin wires connecting to buildings for the phone service from this level. 

• The public or yard sale area is at the bottom. It includes posters and notices that people post on the pole. There are also numbers near the base that identify the pole.

• Poles are black at the bottom from creosote (or a modern substitute) to protect the pole from rotting.

• Support cables run down on a diagonal and attach to a stake in the ground. Draw these lines straight because they are under tension. They keep poles upright by opposing lateral forces. Those lateral forces may come from 1) Turns in the road, 2) Systems of heavy cables branching off to the side, or 3) Dead ends.

• All hanging wires follow a catenary curve between the points of support. These can generally be best drawn with the artwork turned upside down.
If there are utility service professionals reading this post who can help me correct any errors, please let me know in the comments.
Read more:
A highly visual book that I recommend: 

Archetypical utility pole (parts and diagrams)
Telephone power and CATV poles (more photos and explanations)
Wikipedia on Utility Poles gives an international scope


cherngzhi said...

Gosh. I never bothered to figure these out. Thanks for the knowledge James

Tom Hart said...

Love this. Sort of Eric Sloane for the more modern age. Personally, I've become fascinated by some RR crossing signals that I walk by each day. They look almost human, or at least humanoid, to me with their multiple "arms" and hooded "eyes". They're on my short list of things to paint.

Clara Lieu said...

I really enjoy the specificity of this post, and your ability to make everyday, mundane things like a telephone pole fascinating and wonderful. Many of my students seem to think they have to travel to some faraway, exotic place to find subject matter for their artwork. I think these telephone pole drawings show that something that's right outside your window, that you pass by everyday can be just as compelling as what's on the other side of the planet! One of my favorite parts of being an artist is the research you get to do on your subjects, and how your understanding of the subject is so greatly enhanced by that research.

Celia said...

Amazing. Hard to think I've seen them all my life and not really understood their construction. Wireless indeed. LOL

Unknown said...

I posted a lunchtime sketch of the utility pole off our studio's rooftop deck this past March. I didn't do all the research you did, but it turned out that one of my friends works in that area and she was able to identify the various parts for me. I pointed her to your blog entry, I think she'll like it! :)

Steven Powers (SMP) said...

Very good and detailed. BTW...The lowest rung as you have described as "Communications" is accurate but a little bit more information is that in the top / first painting there is a splice box attached to the cable. That is a fiber optics splice case that is lashed to the cable and is the point that customers can be serviced from. Quite often that fiber will be spliced in then will traverse the pole to the ground and brought to the building through underground conduit. This is just a little bit of info for those who might be curious. Thank you for sharing.

Sham mustapha said...

Love reading this article...informative...beautiful drawings...thumbs up.

Sham mustapha said...

Love reading this article...informative...beautiful drawings...thumbs up.

Unknown said...

It should be noted that while the conversion to LED lighting has many advantages there’s also a significant drawback. Sodium vapor lights have a relatively narrow spectrum. Astronomers have special filters that eliminate the yellow colored light allowing continued use of telescopes for both visual and photographic use. The white LED lighting has a brighter and much wider spectrum. The conversion to LED lighting pushes the night sky that much further back. From my home in Illinois, the night sky is the color of a Creamcsicle. From my home in New Mexico, a dark sky protected state, I can see the sky the way Galileo saw it. As it is now, a regretfully few number of people have seen the Milky Way span across the sky from horizon to horizon.

David Teter said...

Great post James. I have long been fascinated by utility poles and things like this from the urban and industrial landscape and have done my own paintings of them although I did not know all of the anatomy of them. Now I do. Thanks for the links.

On the light issue Ken Davy brings up. You can find your posts on them by typing 'sodium vapor' in the blogger search box upper left. One of the best things about your blog is the mechanics of our modern world and how that relates to artists.
Thanks James

Alan Postings said...

As the artist Robert Crumb said in 'Crumb (1994)' about telephone poles - "You just can't make this stuff up". Great article. Thanks

Steve said...

Where else but Gurney Journey would we be given a soulful, heartfelt portrait of a young mother nursing her baby -- soon followed by an illustrated guide to everything you ever wanted to know about utility poles, but were afraid to ask. Thanks for another demonstration why this is my best web stop of the day. The variety and depth of GJ continues to be in a class by itself.

jamie said...

As a previous commenter noted above, it reminds me of a sublime part of that documentary on Robert Crumb where it focused on his obsessive attention to such omnipresent industrial environments and his detailed pen + ink reference sketches of everyday “visual junk” that we are so immersed in we no longer really see it anymore.
There’s a Time Magazine article on these “banal referents” with this quote:
“People don’t draw it, all this crap, people don’t focus attention on it because it’s ugly, it’s bleak, it’s depressing,” he says, “The stuff is not created to be visually pleasing and you can’t remember exactly what it looks like. But, this is the world we live in; I wanted my work to reflect that, the background reality of urban life.”

Linda Navroth said...

They also carry missing pet posters and yard sale signs! What would we do without them?

Unknown said...

Pretty accurate information, although residential areas only require one pot about every 6 homes. Commercial areas require either two or three pots every one or two businesses.

Unknown said...

Pretty accurate information, although residential areas only require one pot about every 6 homes. Commercial areas require either two or three pots every one or two businesses.