Most electrical construction projects involve some form of concrete work. With rising labor costs and the perennial need to keep projects on schedule, it makes sense to consider using precast concrete products.

So says Doug Carter, president of Carter Electric Inc., Apopka, Fla. He founded his company in 2003 and has been using precast ever since.

“I have been using precast manholes and pole bases my entire career. They are normal to me,” Carter said, whose company specializes in medium-voltage underground infrastructure, roadway lighting, government and commercial construction and renovation, theme park work, wastewater treatment plants, data centers and maintenance.

“We have utilized some pour-in-place pole bases, but only small ones for bollard lights,” he said. “We have found it to be much cheaper to use precast for manholes, bollards, light pole bases, and transformer and switchgear pads. Precast works better for us under 99.9% of the circumstances. The only time pour-in-place would be used would be if it was required by the project drawings or specifications.”

The advantages of precast

Carter Electric is among more than 200 electrical contractors served by Lindsay Precast Inc., Canal Fulton, Ohio, a precast concrete manufacturer.

Lindsay Precast’s electrical product line includes light pole bases and pads, maintenance holes and utility vaults, substation foundations and pads and transformer vaults and pads.

Utility structures produced by the precast concrete industry overall include utility vaults, utility maintenance holes, pull/splice boxes, utility trenches, equipment enclosures, equipment pads, tunnel vaults, panel vaults, light pole bases and more.

“The reasons electrical contractors order our products are reduced on-site schedules, reduced costs and better quality,” said Mike Freshwater, preconstruction manager for Lindsay Renewables, a division of Lindsay Precast, which maintains plants in Colorado, Florida, North Carolina, Ohio, Pennsylvania and South Carolina.

“We precast and integrate all of our products in weather-
controlled buildings, which eliminates weather delays and labor shortages,” Freshwater said. “It takes a shorter duration to produce and install a better quality product.”

The Lindsay Precast website boasts more than two million annual work-hour savings for customers using its products. And by no means is Freshwater alone in stating the advantages of using precast.

“There’s no waiting for the products to cure on the job site,” said Will Gold, an engineer for the American Concrete Institute (ACI), Farmington Hills, Mich. “Placement is much faster to get whatever structure up and running.”

Lindsay Precast makes a variety of precast concrete items for the electrical utility industry, including containment vaults such as this.

Quality standards and specifications

ACI is an independent organization that determines the standards and writes general building codes for concrete in all forms. ACI Code 350 pertains to precast concrete and the electrical industry. It addresses maintenance hole construction and more.

Beyond ACI standards, ASTM International standards relate to manufacturing and testing standards for precast items, including:

ASTM C857: Standard Practice for Minimum Structural Design Loading for Underground Precast Concrete Utility Structures

• ASTM C858: Standard Specification for Underground Precast Concrete Utility Structures
• ASTM C891: Standard Practice for Installation of Underground Precast Concrete Utility Structures
• ASTM C1037: Standard Practice for Inspection of Underground Precast Concrete Utility Structures

Outfoxing Mother Nature

Like Freshwater, Gold said quality is easier to control with precast because manufacturing takes place in a controlled environment. 

“Precast concrete producers can more easily control concrete mixing, design and testing,” he said.

Pour-in-place concrete companies with proper certifications also produce high-quality results, Gold said, but durability and quality can be more challenging to achieve in the field.

That’s because terrain and weather conditions can affect the quality of poured concrete. Extreme heat conditions require slow-cooling methods such as wrapping concrete in wet burlap to keep it from cracking and drying out too quickly.

Areas with high water tables require prolonged effort to displace water while concrete sets.

“The water table is normally high in the areas we work here in Florida, so we assume we normally will have to dewater to install precast structures, but it would be the same scenario if we were doing pour-in-place,” Carter said. “Dewatering is expensive. The difference would be the length of time the dewatering needed to run. With precast, we spend less time doing this.”

High concentrations of sulfates in soils can compromise concrete’s structural integrity and longevity. Whether precast or pour-in-place, concrete companies with proper industry certifications know to adjust their concrete mixes to accommodate different soil types, Gold said.

Those are just a few reasons it’s so important to look for certifications among concrete firms, whether using precast or pour-in-place.

Estimating and planning

Hiring a concrete firm to pour on-site can involve extenuating circumstances that increase work hours and final costs. With precast concrete, Carter said, “We order and pay for precast just like we would for conduit, wire or any other material we have delivered to the job site.”

That aspect can simplify the estimating process as well. Time frames do differ. Instead of scheduling a pour at a specific location, precast orders must be placed four to six weeks in advance to allow for production, curing and product delivery.

Customization

Pour-in-place concrete offers customization. Using standardized molds with precast helps keep costs down, but forms can be customized depending on the job.

“Creating a mold involves some expense, but once it exists it can be used again and again on the order of a cake pan or muffin tin,” Freshwater said.

Carter said that, in some instances, he has worked with people to design maintenance holes and other items unique to certain projects.

“If they don’t know what is needed to make it work in the field, we will help them design what is needed,” he said. “We’ve done that a lot with theme parks. Yes, for sure, these components are all pretty much similar but there can be differences in the sizes and quantities of conduits for the job or application. For example, if it is an electric manhole or telecom manhole, the conduit quantity and configurations vary, and anchor bolt sizes and spacing on light poles vary.”

Flexibility

Another scheduling factor to consider is that there’s more flexibility with timing delivery of precast products to the job site. Pour-in-place concrete must be poured within 45–60 minutes of leaving the plant.

“In rural areas involving great distances, one hour might not be enough time to make it from the plant to the job site,” Freshwater said. “We can deliver as many flatbed truck loads as the site can unload. We pour well in advance and store items at our sites until needed.”

Lindsay Precast has 10 million square feet of storage at its nine locations.

For big work crews, larger quantities of products can be delivered. For smaller ones, less can be delivered per day.

For unloading precast items, Freshwater recommended using a crane or hybrid forklift/crane called a telehandler. Using certified precast operations closest to work sites can also keep costs down. Both the National Precast Concrete Association (NPCA) and Precast/Pressurized Concrete Institute maintain a national directory of members on their websites.

Less red tape and permitting

Still another benefit of using precast for electrical contractors is that they don’t have to pull a building permit to use precast in most cases, whereas most pour-in-place structures require one.

“Normally you don’t need engineered drawings for a permit, and these are not normally inspected by the AHJ [authority having jurisdiction], because a certified precast manufacturer already has necessary certifications and they provide engineered shop drawings for submittal to the engineer of record for the project,” Carter said.

Reputable industry-certified precast concrete manufacturers already work with inspectors within their regions and regularly provide proof of their manufacturing practices, certifications and standards, Freshwater said.

More than 75% of state Departments of Transportation (DOTs) recognize the NPCA Plant Certification, and there are more than 375 NPCA-certified plants in North America, according to the NPCA website.

It’s common practice for state DOTs to recommend precast companies to contractors that have successfully bid on state and federal contracts.

“DOT certifications are state-specific and can be difficult to get due to varying requirements that can be more strict than NPCA and ACI,” Freshwater said.

According to Freshwater, using precast also saves having to hire labor for forming the concrete, tying rebar, testing with third-party labs or finishing the concrete. 

“The time saved is a net benefit to general contractors and electrical contractors, and it also minimizes risks,” he said.

“I would recommend precast to just about anyone,” Carter said. 

“Unless a company is large enough to have a concrete crew on staff, precast is the way to go,” he said.

Lindsay Precast Inc. / stock.adobe.com: amorn / Lindsay Renewables