Electrical Duct Banks in Casper, Wyoming

Cable is cheap to pull and miserable to replace. A duct bank exists so the electrician can pull new conductors in ten years without digging up a parking lot. That promise only holds if the conduits are straight, clear, correctly spaced and protected from the soil, the frost and the equipment that will drive over them for decades.

A duct bank is a bundle of conduits laid in a trench, held in position by spacers, wrapped in rebar when the design calls for it and encased in concrete. It carries primary power to a building, feeds a pad-mount transformer, links a switchgear room to a pump house or runs between two buildings. The concrete is the armor. The conduit is the road the cable will travel.

We build duct banks as precision work in a muddy trench. The pull boxes, bends and elevations have to line up, or a cable that is easy to draw on paper jams in the field.

What goes into a duct bank

Our duct bank scope covers excavation, base preparation, conduit and fittings, spacers, rebar, concrete or flowable fill encasement, backfill and restoration. We also set the manholes, handholes and pull boxes that punctuate the run, working with the manholes, vaults and structures crew on the same site so the elevations meet.

The conduit type follows the specification: PVC for most buried power, rigid steel or HDPE where the design requires it. Joints are solvent welded or fused, and each run gets a pull string and a proofing mandrel. Spare conduits are included when the drawings show them, and often they are the best value on the job, since a spare costs a fraction of re-trenching later. We cap and mark every spare and record its location.

Spacers, tie-downs and a straight pour

The trench is cut to width and depth with a firm, level base. Spacers go in at set intervals, and conduit is assembled in layers so the bank holds its shape. Rebar, where specified, goes in with the required cover. Then the tie-downs. Concrete is heavier than the conduit is buoyant, and empty PVC will float up through wet concrete unless it is strapped down and the pour is placed in controlled lifts.

The placement matters as much as the layout. We pour from one end and keep the concrete moving, vibrate gently so voids do not form between conduits and avoid dumping on the conduit from height. Many banks are placed by pumping and placement through a hose that reaches the trench from the road. Red dye in the concrete, where specified, warns future excavators that energized cable lies below. The bank is cured, and the trench is backfilled only after the concrete has gained enough strength.

What drives the price of a bank

The conduit count and size set the width of the trench and the volume of concrete. A bank of twelve conduits costs far more than a bank of four, mostly in concrete, labor and spacer hardware. Depth adds shoring and spoil. Crossings with other utilities add hand digging, protection and time.

Site factors matter too. A long run through open ground moves fast, while a run under existing paving adds sawcutting, demolition, traffic control and repaving. Restoration can be a third of the total in a developed area. We list those items separately and propose an alignment that cuts crossings, which is often cheaper than a straight line on the drawings.

Utility rules, code editions and conflicts

The electrical code governs the conduit fill, bends, burial depth and encasement. Wyoming's fire marshal page names the 2026 National Electrical Code for electrical work, while other Wyoming sources still cite the 2023 edition, so the project team should confirm the edition with the department and the local jurisdiction. We build to the drawings and the edition the engineer lists, and we raise any conflict in writing.

The serving utility has its own standards for primary duct banks: minimum cover, bend radius, pull box spacing and inspection. These often exceed the code. We get the utility's construction standards at the start of the job, and we call the utility's inspector before we pour, not after. A bank that fails inspection after the concrete sets needs a jackhammer.

Fitting a bank into the schedule

Duct banks sit on the critical path for energizing a building. The electrical contractor needs them complete before cable pulls, and the utility needs the pad and the vaults in place before it schedules its crew. Late duct banks hold up the certificate of occupancy more often than any interior item. We order conduit, fittings and structures early, and we place the first pour where it releases the next trade.

Winter changes the plan. Concrete encasement needs cold-weather protection, and the trench bottom cannot be frozen. We may use flowable fill with a heated mix and insulating blankets, or hold the pour until a warm window. In the Casper area, the long, cold season means the schedule should carry weather days. Out at Glenrock, a large coal-fired generating station is a reminder that heavy electrical infrastructure shares this region with every other kind of construction, and that its contractors compete for the same crews and trucks.

Who buys duct banks

Electric utilities and energy companies need banks for substations, switching stations and customer service. Commercial and industrial owners need them for buildings with large electrical loads. A data center may need multiple banks for redundant feeds, with separation between circuits to survive a single dig-in.

Communications are the other half of the story. The Wyoming Business Council approved $617,483 in grant funding for Natrona County to install about 30,000 linear feet of fiber optic cable in and around the airport business park on Airport Parkway. Fiber and power banks often share a corridor, and when they do, we coordinate separation, depth and the pull boxes so that each system is accessible without disturbing the other.

Send the one-line and the site plan

Send the electrical one-line, the duct bank details and the utility's standards. We will give you a price, a pour plan and a schedule that works with the cable pull.

Questions Owners Ask

Why encase conduit in concrete instead of burying it in sand?

Concrete protects the conduit from future digging, holds the geometry under load and spreads the weight of vehicles. It also keeps the conduits from shifting during backfill and helps in areas with frost movement. Direct-buried conduit is cheaper in the short run, but encasement is often required by the utility, the engineer or the owner for primary power.

How do you stop conduit from floating when you pour?

We strap or tie the bank to the base or stakes, fill the conduit with a small amount of water when allowed and place concrete in lifts. Spacers keep the conduits apart, and the pour proceeds from one end so the concrete flows around and under the pipes. The result is a bank that holds its elevations from end to end.

What is the difference between a duct bank and direct burial cable?

Direct burial cable is laid in the ground without conduit, and replacing it means excavating. A duct bank leaves a clear path, so cable can be pulled out and replaced. For primary power, critical facilities and anywhere future change is likely, a duct bank is worth the extra cost.

Do you test the conduit?

Yes. After the concrete cures, we pull a mandrel through each run to prove it is clear and straight, and leave a pull string in place. Any obstruction is located and fixed before restoration, since fixing it later means excavating the bank. We record the results and hand them over with the as-builts.

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