Last month’s article finished looking at the differences between residential and commercial electrical estimating. This month, we will talk about commercial versus industrial estimating.

We use the same line-item estimating methods for industrial electrical estimating as we do for commercial. However, adjustments to the methodology are needed to deal with the differences between the two types of work. 

What is industrial work?

First, I want to define industrial work in the context of electrical estimating: jobs that involve the manufacturing, processing or production of goods, typically in settings like factories, plants or mills. This includes projects such as water, wastewater, food processing, paper mills, automotive factories and aerospace, just to name a few.

Comparing costs

One of the most significant differences between the two types of estimating is the cost of the materials. Residential and commercial projects regularly use less expensive materials, including commercial-grade wiring devices, Romex wiring, metal-clad wiring and electrical metallic tubing. 

Industrial-grade materials are most often  more robust—meaning more expensive. They can include industrial-grade wiring devices, galvanized rigid steel (GRS) and PVC-coated galvanized rigid steel. 

The conduit fittings and supports for the conduit systems are more expensive as well. Many types of industrial work, including food processing plants, require stainless-steel conduit supports. 

Due to the higher cost of industrial-grade materials, I am much more precise with my takeoffs. I do not depend on miscellaneous markups to cover materials that may be inexpensive in commercial work, but very pricey in industrial work. For instance, consider the support for a junction box. In commercial work, that support may be a few sheet metal screws. For industrial work, the same size box may need a stainless-steel strut rack, which is quite costly. It is very important to review the specifications and plan details to understand the material types each project requires before you prepare an estimate.

Work in specially classified areas

Another important difference between the two types of work is the higher likelihood of working in specially classified areas, such as a corrosive environment or an area with explosive materials. It is critical to know the requirements for these spaces because they are sometimes not defined in the plans. 

It is up to the estimator to know the dangers of the areas they are estimating. For example, did you know that under the right conditions, everyday flour is explosive? I learned that from one of the electricians I worked with when I was preparing my first estimate at a bread baking plant. 

Also, industrial materials are generally more difficult to install, creating higher labor costs. Again, the specifications and details on the plans are very important to review and understand. Unfortunately, this can sometimes be difficult, particularly in the case of conduit requirements. I often see contradictions between the specifications and the plans regarding the types of materials required for the project. 

Of course, this is important for material costs, but can have an even bigger effect on the difficulty of installation. For instance, I recently read a specification that required PVC-coated GRS for exposed conduit. However, a table on the plans required PVC Schedule 80 for exposed conduit. That is quite a difference in material and labor costs.

Another area of concern for a company just learning to estimate and install industrial work is process controls. While commercial work usually does include some controls, industrial work often includes extensive and complex control systems. 

During my time as an estimator, I have watched an evolution in the process controls specified. Because of the increasing complexity of control systems, and the failures of many electrical contractors to implement them correctly, most of the industrial project estimates I prepare require a company specializing in controls to do this work. It is essential that the estimator understands what the control contractor must do versus the EC. 

The question of testing

The last thing I want to mention in this part of the series is testing. Most often, the commercial projects I prepare estimates for let the electrical contractor do the testing. On the other hand, most industrial estimates I prepare require a third-party or independent company to do it. Also, the testing for industrial projects is often part of an overall commissioning process, which requires cooperation between many project designers and contractors.

As usual, please be careful when preparing estimates when you are unfamiliar with the work.

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