Duct Bank Spacers
Duct Bank Spacers for Reliable Underground Conduit Systems
NEC-compliant conduit spacing solutions for data centers, utilities, transportation, and critical power projects.
Duct bank spacers are engineered plastic components that keep underground electrical conduits properly aligned inside concrete-encased duct banks. Laird Plastics supplies durable duct bank spacers, PVC conduit spacers, and electrical duct spacer systems that maintain code-compliant separation, improve concrete flow, and protect cables from damage over the service life of the installation.
Shop Duct Bank Spacers by Configuration & Application
Choose from standard PVC conduit spacers, heavy-duty duct bank spacers, and stackable systems for complex multi-layer duct banks. Laird Plastics can also help with project-specific layouts and custom spacing requirements.
Standard PVC Duct Bank Spacers
Most PopularLightweight PVC conduit spacers designed for typical commercial and utility duct banks where standard burial depths and load conditions apply.
Multi-Way Electrical Duct Spacers
High CapacityGrid-style conduit spacers with 4-way, 6-way, and 9-way patterns that keep dense duct banks organized for large power and telecom corridors.
Stackable / Multi-Layer Systems
Complex LayoutsStackable duct bank spacer systems that simplify building multi-layer banks and stepped elevation layouts for congested underground corridors.
Heavy-Duty & Specialty Spacers
EngineeredHDPE and specialty conduit spacers for deep burial, corrosive soils, high-load areas, and utility projects with specific standard drawings or NEC constraints.
Quick Facts: Duct Bank Spacer Selection & Performance
Use these typical parameters as a starting point when sizing and specifying conduit spacers. Always confirm final details with your engineer of record, NEC requirements, and local utility standards.
| Parameter | Typical Range / Options | Design Guidance | Common Use Cases |
|---|---|---|---|
| Conduit diameters Core Spec | 2", 3", 4", 5", 6" Schedule 40 / 80 PVC or equivalent. | Match spacer pockets to outside diameter of the conduit. Mixed sizes may require specialty spacers or transition pieces. | Feeder circuits, primary distribution, telecom, and fiber backbone runs. |
| Way configurations | 2-way, 3-way, 4-way, 6-way, 9-way, and stacked multi-layer assemblies. | Select pattern based on total circuit count and available trench width. Higher way counts reduce excavation but increase bank height. | Data centers, campus feeders, substation exits, and urban duct corridors. |
| Material PVC / HDPE | Rigid PVC for standard duty; HDPE or composite for heavy-duty, deep burial, or corrosive environments. | Consider soil chemistry, backfill, groundwater, and expected loads from traffic, structures, or future development. | Utilities, DOT projects, industrial plants, renewable energy sites. |
| Vertical spacing | Typical spacer spacing 4–7 ft along the run, depending on conduit size and weight. | Place spacers closer together on larger or heavily loaded conduit groups and at changes in direction, elevation, or bank geometry. | Long straight runs, sweeps, vertical risers, and terminations. |
| Code alignment NEC | Spacer layouts are designed to support NEC and utility spacing practices for underground duct banks. | Use project drawings, NEC articles, and local utility details as reference for separation distances and bank geometry. | Engineered electrical duct banks for new construction and retrofits. |
| Environment | Standard, corrosive, high-groundwater, freeze/thaw, and high-load surface conditions. | Coordinate spacer selection with conduit type, encasement concrete, cover depth, and site geotechnical recommendations. | Parking lots, road crossings, substations, campuses, airports, and ports. |
| Lead times | Stock configurations often available; project quantities typically ship within 3–7 business days. | Provide conduit size, way count, footage, and required delivery date early in design to avoid schedule delays. | Fast-track projects, shutdown windows, tie-ins, and expansions. |
How to Choose the Right Duct Bank Spacers for Your Project
Use these practical guidelines to match conduit spacers to your duct bank design, installation environment, and construction schedule. For complex layouts, our team can review drawings and recommend a complete spacer package.
Start with conduit size & circuit count
The outside diameter of your electrical conduits and total circuit count determine the spacer pattern and pocket configuration.
- ● List all conduits by size (e.g., 8 × 4", 4 × 3", 2 × 2").
- ● Group circuits by voltage class, service, or destination if required by NEC or utility standards.
- ● Select multi-way spacers that accommodate your highest conduit count per layer.
Match material to environment & loading
Underground conditions and surface loads influence whether standard PVC spacers are sufficient or if heavy-duty options are recommended.
- ● Use standard PVC conduit spacers for typical commercial and light-industrial runs.
- ● Consider HDPE or composite spacers for deep burial, corrosive soils, or heavy traffic above.
- ● Coordinate with geotechnical reports and utility or DOT standard details.
Plan spacer spacing and installation sequence
Proper placement during installation keeps conduits aligned and reduces labor during concrete placement and cable pulling.
- ● Place spacers every 4–7 ft along the run and at changes in direction, risers, and terminations.
- ● Build duct bank layers progressively, checking level and alignment as you go.
- ● Secure conduits to spacers as needed to prevent flotation or movement during pour.
Duct Bank Spacer FAQs
Get direct answers to the most common questions contractors, engineers, and owners ask about conduit spacers, NEC compliance, and underground duct bank design.
Why are duct bank spacers required in underground electrical installations?
Duct bank spacers are used to keep conduits separated, aligned, and supported inside a concrete encasement. Without spacers, conduits can float, shift, or touch during the pour, leading to pinch points, inadequate concrete cover, and difficult cable pulls. Properly spaced conduits help installers meet NEC and utility standards, maintain thermal performance, and reduce the risk of insulation damage during initial and future cable pulls.
How far apart should I place duct bank spacers along the conduit run?
A common rule of thumb is to place duct bank spacers every 4–7 feet along the length of the duct bank, depending on conduit size, weight, and site conditions. Heavier conduit bundles, deep excavations, and alignment-critical sections (such as sweeps, risers, and transitions) may require closer spacing. Always follow project specifications, engineering drawings, and local utility requirements when determining spacer spacing.
How do I choose the right spacer for mixed conduit sizes in one duct bank?
When your duct bank includes a mix of conduit sizes, you have several options. You can use multi-way spacers with uniform pockets sized for the largest conduits and install reducers or fillers, or you can use specialty spacers with pockets sized for each conduit diameter. A third approach is to separate mixed sizes into different rows or tiers with their own spacer pattern. Sharing a conduit schedule and plan view with Laird Plastics allows our team to recommend the most efficient spacer configuration.
Are PVC duct spacers strong enough for deep burial or heavy traffic areas?
Standard PVC conduit spacers are suitable for many commercial duct banks, but deep burial, heavy structural loads, and high-traffic surfaces may justify heavy-duty HDPE or composite spacer designs. In those conditions, spacer durability, creep resistance, and long-term stability are critical. If your project involves deep encasement, high cover, or future surface loading, Laird Plastics can help evaluate whether a heavy-duty electrical duct spacer is appropriate.
What information does Laird Plastics need to quote duct bank spacers?
To provide an accurate quote and lead time, we typically ask for: conduit sizes and counts, way configuration (2-way, 4-way, 6-way, 9-way, etc.), total duct bank length, project location, burial depth or cover, and any applicable utility or owner standard details. If you can share a one-line or plan view drawing, our team can help translate that into a complete duct bank spacer bill of materials.
Need a complete duct bank spacer package for your next project?
Whether you’re building a new data center, utility corridor, campus feeder, or substation exit, TrenchSafe duct spacers and Laird Plastics’ nationwide distribution give you engineered solutions, reliable lead times, and support from design through installation.