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Electrical Artistry

Posted by Power Partner MN on Apr 2, 2018 2:51:31 PM

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They were a series of educational magazines about animals written for children. I devoured every single one, becoming an expert (in my own seven-year-old evaluation) on all things that swam, slithered, and scampered. My favorite section in every issue was a two-page spread with an anatomical diagram showing the skeleton, muscles, and organs of the featured animal. I was amazed by how the arteries and veins of the creature spread in an elaborate web throughout the organism—connecting and supplying everything at once.

I haven't opened a zoobook in probably 25 years, but those anatomical diagrams came back to me when I saw the project my friend Nate Nord, master electrician, was working on. I was in the basement of a school receiving an addition and Nate was pointing out the electrical grid that fanned out in a hundred different directions from the main breakers.

An animal like a zebra—or you and me for that matter—doesn't need to worry about how to lay out its arteries and veins. Thankfully, these complex systems are all mapped out in our DNA, the product of countless generations of refinement. Horace Mann Elementary School in St. Paul, MN however, doesn't have the benefit of a million years of evolutionary biology to array it's electrical outlets, networking, and lighting controls systems. It has to rely on the work of craftsmen. Hundreds of hours of work by skilled & dedicated professionals who can make those separate elements come together in a safe and functional tapestry of precisely arranged conduit.

 

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For those of you who have never toured a large industrial facility—or even the nether regions of a typical commercial building—the electrical requirements of these structures are met with hundreds of feet of galvanized steel conduit that serve as the arteries and veins of the structure's electrical system. A single one of these conduits might house as many as 400 bundled insulated wires, responsible for supplying power to one electrical subsystem or another. Each of these conduits runs from the main switch-box to many smaller distribution hubs throughout the building, and then gets divided further into the power outlets, banks of overhead lights, AV, networking, and communication systems that we as end-users take for granted and interact with in our everyday lives.

 

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When I plunk myself down to start on a blog (like this one) I don't think about how the power infusing my MacBook begins in a box over a hundred feet away and is routed through eight layers of gizmotry before passing into the intel processor that spellchecks my work (for things like gizmotry). Ok clearly my understanding of how electrical distribution works has some limitations. But even I can appreciate the time and skill that goes into bending the precisely curved conduits—sometimes coupled in groups of a half dozen or more—into tight parallel formations that snake cleanly around the labyrinth of HVAC ductwork in the bowels of Horace Mann Elementary School.

How is this remarkably complex & precise network of conduits created you ask? Good question. I was pretty sure that was done by magic too. Then Nate showed me a long-handled tool with a curved channel at one end. This, he tells me, is a conduit bender. Ok, so it's not exactly a magic wand, but when you see it used by a professional it still seems pretty wild. Using the long handle as a lever while guiding a pipe through the channel, Nate creates a 22.5° bend, then further down the length of the pipe, another bend that's 45°.  "That's how it's done," Nate says. I ask him if all conduit work is shaped using this technique. He tells me we will get into that later, but it depends on the nature of the job and the raceway that's used. "Raceways" are what electricians call the conduit. The most common raceways used for electrical work are IMC (intermediate metal conduit), EMT (electrical metallic tubing), and RMC (rigid metal conduit) 

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But it's not simply access to the tools that makes this possible. Nate goes on to explain the steps required to properly bend conduit to ensure the pipe is going to be the right length when all is said and done. The bend needs to be properly calculated and executed so it can carry its wires from point A to point B while avoiding the obstacles between. I go on to learn about how to calculate stub take up, back take up, shrink, and gain. These terms refer to the length that is either lost or gained when conduit is bent (90° bends add length to a conduit, whereas obtuse angles subtract length). Even the little bit of math involved in planning a relatively straightforward (heh) bend might surprise you.

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So naturally we'll be using it to calculate the length of the raceway we need before it goes through the bending process. 
Electricians use a "multiplier" as one of the variables in the calculation. While I only gained a very basic understanding of how and when to implement the calculation, I did learn that these multipliers are used to help overcome the problem that "shrink" poses, which is the loss of length in a raceway caused by bending it. Multipliers can vary based on the degree of the bend, the radius of the bend, and the diameter of the conduit. If it seems like that is a lot to remember, that's because it is—though Nate assures me that most of the time he's limiting the variables to only one (the angle of the bend) since a standard conduit is used the majority of the time.

Nate shared some numbers to remember to make things easier (for some reason people always think giving me numbers to remember will make it easier for me to learn something new). A bend of 22.5 degrees had a multiplier of 2.5, and a shrink of 3/16", 30 degrees- a multiplier of 2, shrink of 1/4", and 45 degrees- a multiplier of 1.4, shrink of 3/8". These are some of the more common bends that electricians make, and memorizing these sufficed for the bends that Nate showed me. While creating an offset in one of the raceways, Nate predicted that the three foot metal rod would lose 1.25" after two specific bends in the hand bender. That may not sound like much to fuss over, but precision in conduit bending is the name of the game. The tape measure showed 34.75". Okay Nate, not half bad.

An experienced electrician can do quite a lot with a hand bender, but if the conduit is over 1.5"  in diameter it requires something else to bend it. Often larger heavier material is needed for certain projects that a hand bender (like the one shown above) can't quite handle. "You asked earlier if this was how all pipe bending was done." Nate said, and then he showed me pictures of hydraulic and motorized conduit benders for larger raceways. 

The hydraulic muscles of these machines make easy work of bends that would be impossible for a hand bender (curving a 2" pipe as though it were made of silly putty). But even while using a machine for the heavy lifting, Nate's command of trigonometry needs to stay sharp. It turns out the mechanical understanding of how bends need to be laid out must be carefully thought through when using machinery like this. Variables affecting the shrink frequently change when working with the caliber of conduit that a machine bender is required for. 

Unfortunately, mastering conduit bending with a hand bender doesn't necessarily translate to machine bending. The amount of factors taken into account become staggering with some of the specialized piping. We already know the diameter of the pipe and the radius of its bend need to be identified, but so does the material of the pipe and its rigidity. Not to mention, the bending methods of a particular machine often vary, each producing inconsistent results amongst each other. So how is all of this kept straight? Well for all the cynics out there it turns out that, yes, there is an app for that. Online calculators produce the numbers an electrician needs as long as he/she correctly enters the right numbers. It's one of the perks of living in the 21st century.

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Conduit bending is one of the rare practices that falls inside the shaded region of the Science/Art Venn diagram. The installation of conduit is predicated on whether the electrician knows and can execute the math involved in finding the right bend- science. But producing the bend itself requires hours of practice and cultivating a skill, and when done correctly ends up looking like a masterpiece- art. So if you do happen to ask an electrician what their job is like, and they respond with "well, it's a lot of problem solving and figuring how to piece things together", know that they are being humble. Chances are a more accurate answer would be "I solve problems by combining science and art". And next time you're in a room full of bent metal pipes, take a second to appreciate the art behind it all.

If you would like guidance from an electrician on your career path, get in touch with us by filling out the "Get Guidance from and Electrician" form on the top right of this page and we will reach out to you!

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