3 Common Misconceptions About Transmission and Substation Design

Transmission and substation structures can look straightforward at a glance. But the decisions behind their design are more detailed than most people realize—and that’s where common misconceptions tend to show up.

Below are three misconceptions we hear often, along with clarifications from a structural design and fabrication perspective.

Misconception #1: Bigger structures always mean better safety

Steel structures are designed for the loads provided within the parameters of the project specification. From a structural safety standpoint, “bigger” does not automatically mean “safer.”

*One important clarification: this discussion is about structural safety, not electrical safety. These are two separate discussions.

How structural safety factors are achieved

There are two ways to achieve a factor of safety in structural design:

• Artificially increasing loads to account for uncertainties in how loads are developed
• Artificially decreasing allowable material strength to account for uncertainty in the strength of the structural material

These approaches can be used independently or in combination to create the required safety factor.

Why “rounded-up loads” can be misleading

Sometimes people assume safety improves simply because loads are rounded upward. For example:

• A load of 900 lbs may get rounded up to 1000 lbs
• A load of 32,750 lbs may get rounded up to 35,000 lbs

At first glance, the larger increase can appear to provide a greater safety factor. But when you look at the ratios:

• 1000/900 = 1.11
• 35,000/32,750 = 1.07

The numbers may look larger, but the safety factor difference is smaller than it seems.

What to focus on instead of size:

Assuming the engineering is correct, one of the biggest factors that affects structural safety is quality production.

The best engineering is useless if the quality of production does not meet the intended design.

Misconception #2: Standard designs work everywhere

People often assume these structures are “cookie-cutter.” They may look that way to the naked eye, but when you dig into the specifics, they are far more custom than they appear.

Utilities often face a real tension between designs intended to fit multiple solutions and custom designs tailored to the application.

When standard designs can increase cost or rework

Almost by definition, a standard design is going to be over-designed for the application it’s being used for.

A helpful comparison is buying a shirt. You have three options:

1. One that is too big
2. One that is too small
3. One that is tailored to fit exactly

If we’re talking about safety, you would never choose the option that is too small. That leaves two options: the tailored one or the too-big one.

With shirts, most people buy the too-big option because tailoring is expensive—shirts typically aren’t made by hand anymore.

Poles are different. Poles are mostly made by hand, so the tailored solution is often cheaper than the “too big” option.

Site conditions that challenge standard designs

Everyone knows about hurricane winds and high seismic zones. But some of the most challenging projects occur when the design is physically restricted, such as:

• Underground utilities limiting the foundation
• Limited space because the owner has run out of room in a substation
• Having to fit the structure in a limited right-of-way

These restrictions can quickly push a project beyond what a standard design can efficiently accommodate. 

Misconception #3: Steel structure design happens after electrical design

For transmission projects, this is mostly correct—but transmission line designers still need an understanding of what is reasonable.

Why it’s more true for transmission projects

In transmission, one of the biggest limitations is balancing:

• How tall to make the structures
• How much tension or sag to apply to the lines

For substation work, whoever is doing the substation design needs to be familiar with structure design, or redesign will inevitably take place.

Substation projects must account for all pieces of equipment—and those pieces need to be in the correct order in the circuit to do their job properly.

When a substation designer is unfamiliar with steel design, it becomes easier to arrange equipment in a way that makes it very challenging for a structural engineer to meet the requirements.

Why these misconceptions continue to show up

These misconceptions continue to come up because people default to thinking that selecting a steel pole is similar to selecting a shirt—just pick S, M, or L.

But these structures are too expensive to be thought of in those ways.

That’s why it’s important to work with a supplier who understands the truth behind these misconceptions and can support the full process—from interpreting requirements to producing structures that meet the intended design. When teams align early and approach structures as engineered solutions—not off-the-shelf items—they’re better positioned to achieve outcomes that are safe, efficient, and appropriate for the application.