Pole Cross Arms for Utility, Power and Electrical Distribution

Utility pole crossarms are horizontal structural members used to support conductors, insulators, communication equipment, and other utility hardware on poles. Crossarm selection depends on the utility construction standard, circuit configuration, conductor spacing, material, loading, pole arrangement, environmental exposure, and project requirements.

Utility crossarms should not be confused with lighting bullhorns or decorative fixture-mounting arms. A utility crossarm is part of an overhead utility-line structure, while a lighting bullhorn or light pole mounting accessory is generally used to position luminaires on a lighting pole. For lighting-pole applications, see steel light pole bullhorns.

Selection Note: Utility crossarm dimensions, material, drilling pattern, conductor spacing, insulator arrangement, bracing, hardware, strength, and installation requirements should be matched to the applicable utility standard, engineering design, NESC requirements where applicable, and project specifications. LED Lighting Supply can help supply product specifications and available configurations, but final line design and structural suitability should be determined by the utility, project engineer, or other qualified utility professional.

What Are Utility Pole Crossarms?

Crossarms are horizontal structural members installed on utility poles to support insulators, conductors, communication equipment, and other overhead-line components. Their arrangement helps maintain the conductor clearances and equipment positioning established by the utility or project design.

Crossarm dimensions are not determined from voltage alone. Selection can depend on:

• Utility construction standards
• Circuit configuration
• Conductor size and spacing
• Insulator type
• Number and location of conductors
• Crossarm material and section properties
• Pole-top configuration
• Crossarm bracing
• Dead-end, tangent, angle, or equipment-loading conditions
• Wind and ice loading
• Hardware and attachment requirements
• Applicable NESC, utility, and project requirements

Because these variables differ among utilities and line designs, there is no universal crossarm length that applies to a particular distribution or transmission voltage.

Selecting the Proper Utility Crossarm

Start with the utility or project construction standard. That document should establish or help determine the required crossarm material, dimensions, hole pattern, insulator locations, conductor spacing, bracing, hardware, and structural loading.

Important information to confirm before ordering includes:

• Utility or owner specification
• Distribution, transmission, communication, or equipment application
• Circuit voltage
• Phase and conductor configuration
• Required conductor and equipment clearances
• Crossarm dimensions
• Required drilling pattern
• Wood, fiberglass/composite, steel, or other specified material
• Crossarm strength and loading requirements
• Brace configuration
• Insulator and pin arrangement
• Pole attachment hardware
• Environmental exposure
• Wind and ice design criteria
• NESC and utility-specific requirements where applicable

Do not select crossarm material from circuit voltage alone. Wood, fiberglass/composite, steel, and other crossarm systems may be used at different voltage levels depending on the utility design and exact product specifications.

Types of Utility Crossarm Materials

Wood Crossarms

Wood crossarms have a long history in overhead electric utility construction. Species, grade, treatment, dimensions, drilling, allowable loading, and hardware requirements vary by utility and application.

Pressure-treated wood may provide protection against decay and biological deterioration, but performance and service life depend on factors such as:

• Wood species and grade
• Treatment system and retention
• Moisture exposure
• Climate
• Mechanical loading
• Drilling and field modifications
• Hardware and attachment details
• Inspection and maintenance practices

Standardized dimensions are commonly used by utilities, but a particular crossarm size should not be assumed suitable for a circuit merely because it is commonly stocked. Match the crossarm to the utility drawing or project specification.

Fiberglass and Composite Crossarms

Fiberglass or fiber-reinforced composite crossarms are used by some utilities where low weight, resistance to certain forms of corrosion or deterioration, dimensional consistency, or other material characteristics are advantageous.

Suitability depends on the specific composite system. Confirm:

• Structural load ratings
• Drilling and attachment requirements
• UV resistance
• Tracking and electrical performance where applicable
• Temperature limits
• Impact and mechanical performance
• Chemical and environmental compatibility
• Manufacturer installation requirements

Fiberglass/composite material should not be assumed unaffected by salt, chemicals, temperature extremes, UV exposure, or mechanical loading. Those characteristics are product-specific.

Likewise, terms such as nonconductive or dielectric should only be used when supported by the exact manufacturer specification and applicable test data. A composite crossarm should not be treated as a substitute for required electrical clearances or utility safety practices.

Steel and Other Crossarm Systems

Steel and other engineered crossarm systems may also be used for specific utility applications. Material, coating, galvanizing, hardware compatibility, structural loading, corrosion exposure, and grounding or bonding requirements should be confirmed from the utility or project design.

Common Utility Crossarm Configurations

Crossarm arrangements vary according to circuit design and utility construction standards. Common configurations can include:

• Single crossarms: Used in many tangent and distribution structures where the specified loading and conductor arrangement can be supported by one crossarm.
• Double crossarms: Used where the utility design requires additional structural capacity, hardware attachment, dead-end support, angle construction, or other line conditions.
• Braced crossarms: Use braces or other structural members where required by the construction standard to support the crossarm and imposed loads.
• Equipment crossarms: Designed to support switches, cutouts, arresters, communication equipment, or other utility components when specified. Equipment support arrangements must match the applicable utility design and loading requirements.
• Custom configurations: Used for project-specific conductor arrangements, unusual pole-top geometry, clearances, or equipment requirements.

The length, spacing, and number of crossarms should come from the actual line design rather than general assumptions such as “8-foot crossarms for distribution” or “12-foot crossarms for transmission.”

Crossarm Loading and Structural Requirements

Utility crossarms are structural components. Their required strength depends on the forces produced by the conductors, insulators, equipment, wind, ice, line angles, dead-ending, broken-wire conditions where applicable, and other design loads established for the structure.

Crossarm selection may require review of:

• Vertical loads
• Transverse loads
• Longitudinal loads
• Conductor tension
• Dead-end loads
• Angle loads
• Wind loading
• Ice loading
• Equipment weight
• Insulator and hardware loads
• Crossarm deflection limits
• Attachment strength
• Pole structural capacity

A single or double crossarm configuration should therefore be selected from the applicable utility design rather than from a generic voltage or load rule.

Utility Crossarm Installation Considerations

Crossarms should be installed according to the utility construction drawing, crossarm manufacturer instructions, and project requirements. Hardware type, bolt size, hole locations, braces, torque requirements, fastener arrangement, and corrosion protection can differ among systems.

Installation considerations can include:

• Crossarm orientation
• Factory versus field drilling
• Bolt and hardware dimensions
• Brace location and angle
• Insulator and pin positioning
• Conductor spacing
• Pole attachment details
• Galvanic compatibility
• Corrosion protection
• Grounding and bonding requirements where applicable
• Utility climbing and maintenance clearances

Do not assume stainless-steel hardware, double nuts, lock washers, or a universal 45-degree brace angle is appropriate for every crossarm installation. Use the hardware and assembly details specified by the utility, manufacturer, or engineered construction drawing.

Utility Crossarm Standards and Compliance

Utility crossarm compliance cannot be established from a single general lighting standard. Requirements depend on the utility, project, material, line configuration, loading, and governing electrical-safety and structural criteria.

ANSI C136.20 should not be represented as a general utility-crossarm requirement. ANSI C136.20 addresses fiber-reinforced composite lighting poles for roadway and area lighting rather than general electric-utility distribution or transmission crossarms.

Depending on the project, utility crossarm requirements may be established through:

• The utility owner’s material specifications
• Utility construction standards and drawings
• Applicable NESC requirements
• RUS or other utility specifications where applicable
• Material-specific standards
• Crossarm manufacturer ratings and test data
• Project engineering requirements
• Local or owner-specific construction requirements

Confirm the exact standards required by the utility or project before ordering rather than assuming a crossarm complies because it is described as a utility product.

Choosing a Replacement, Standard, or Custom Crossarm

The best purchasing path depends on whether the crossarm is replacing an existing component or is part of a new utility structure. A matching replacement may be appropriate only when the existing construction drawing, dimensions, drilling, material, hardware arrangement, and required rating are confirmed.

• Replacement crossarms: Compare the existing crossarm and current utility specification for overall length, section dimensions, material, treatment or finish, hole pattern, brace locations, and attachment details. Do not assume an older installed crossarm represents the current approved construction standard.
• Standard stocked crossarms: These may be suitable when their published dimensions, drilling, material, and ratings match the utility or project requirements without modification.
• Factory-drilled crossarms: Factory drilling can help reduce field modification and support repeatable installation when the drilling pattern is supplied or approved by the utility or project authority.
• Custom crossarms: A custom configuration may be needed for nonstandard hole patterns, pole-top arrangements, conductor locations, equipment layouts, or project-specific construction details.
• Material substitutions: A change from wood to composite, steel, or another material should be approved against the applicable utility standard and line design. Matching dimensions alone does not establish equivalent structural, environmental, electrical, or installation performance.

For new construction, replacement of damaged components, or material substitutions, use the current utility drawing or an established engineering specification as the purchase basis.

What to Provide When Requesting a Crossarm Quote

Providing the utility drawing or crossarm specification is the best starting point. When available, include:

• Utility or project name
• Utility construction drawing
• Crossarm material
• Overall dimensions
• Hole pattern or drilling drawing
• Quantity
• Line or circuit application
• Required structural rating
• Treatment or finish
• Hardware requirements
• Applicable standards or utility specifications
• Environmental conditions

LED Lighting Supply can help identify available crossarm products that match the supplied dimensions and specifications. The utility or project engineer should establish conductor spacing, structural loading, electrical clearances, line configuration, and final construction requirements.

Ready to Source Utility Pole Crossarms?

Speak with a Product Specialist about your utility pole project. Whether you are replacing existing crossarms or sourcing components for a new installation, provide the utility specification, dimensions, drilling pattern, material, loading requirements, and quantity whenever possible.

Request a pole or crossarm quote, and our team can help match available products to your established project requirements.

Pole Cross Arms for Utility, Power and Electrical Distribution FAQs

How Do I Select The Proper Utility Pole Crossarm?

Select a utility pole crossarm from the utility or project construction standard, which should establish or help determine the required material, dimensions, hole pattern, insulator locations, conductor spacing, bracing, hardware, and structural loading. Confirm the utility or owner specification, application, circuit and conductor configuration, clearances, material, drilling pattern, loading requirements, attachment hardware, environmental exposure, and applicable requirements before ordering.

Can I Choose A Crossarm Length Based On Circuit Voltage?

No, utility crossarm dimensions are not determined from voltage alone. Length and configuration depend on utility standards, circuit configuration, conductor spacing, insulator arrangement, loading, pole-top configuration, bracing, environmental conditions, hardware, and project requirements.

What Is The Difference Between A Utility Crossarm And A Lighting Bullhorn?

A utility crossarm is part of an overhead utility-line structure that supports conductors, insulators, communication equipment, and other utility hardware. A lighting bullhorn is generally a light pole mounting accessory used to position luminaires on a lighting pole.

How Should I Choose Between Wood, Fiberglass/Composite, And Steel Crossarms?

Choose the crossarm material specified by the utility or project design rather than selecting material from circuit voltage alone. Wood, fiberglass/composite, steel, and other systems may be used at different voltage levels depending on the utility design and exact product specifications.

When Is A Double Crossarm Required?

A double crossarm is used when the utility design requires additional structural capacity, hardware attachment, dead-end support, angle construction, or other line conditions. The single or double crossarm configuration should be selected from the applicable utility design rather than a generic voltage or load rule.

What Determines A Utility Crossarm's Required Strength?

Required crossarm strength depends on forces from conductors, insulators, equipment, wind, ice, line angles, dead-ending, broken-wire conditions where applicable, and other design loads established for the structure. Review may include vertical, transverse, and longitudinal loads, conductor tension, attachment strength, crossarm deflection limits, and pole structural capacity.

What Information Should I Provide For A Utility Crossarm Quote?

Provide the utility drawing or crossarm specification whenever possible. Include the utility or project name, material, overall dimensions, hole pattern or drilling drawing, quantity, line or circuit application, required structural rating, treatment or finish, hardware requirements, applicable standards, and environmental conditions.

How Can I Verify A Utility Crossarm Meets Project Requirements?

Confirm the exact standards required by the utility or project before ordering rather than assuming a crossarm complies because it is described as a utility product. Requirements may be established through utility material specifications, construction standards and drawings, applicable NESC requirements, material-specific standards, manufacturer ratings and test data, and project engineering requirements.