Aluminum Cable Trays for Solar Power Systems: Selection, Sizing and Installation

Why Aluminum Cable Trays Dominate Solar Power Systems

Aluminum has a density of 2.7 g per cubic cm, roughly one-third of steel at 7.85 g per cubic cm. A 300 mm ladder tray weighs about 4.5 kg per meter in aluminum versus 13.5 kg per meter in hot-dip galvanized steel. That difference cuts shipping cost, reduces the load transmitted to PV mounting structures, and makes field handling safer for installation crews.

Aluminum is also non-magnetic, which prevents eddy-current heating when the tray carries single-core AC conductors or high-frequency monitoring cables. Its surface oxide layer re-forms immediately after scratching, so a dent that would start rust on a galvanized tray does not compromise an aluminum tray. These properties make aluminum the material that best matches the outdoor, high-exposure operating profile of solar power systems.

Material Grades and Corrosion Management

For a solar power system, 6063-T6 aluminum alloy is the standard starting specification because it balances structural strength, extrusion cost, and proven outdoor performance.

Alloy grade and temper

6063-T6 delivers a minimum yield strength in the range of 170 MPa, which is sufficient for ladder and trough trays on standard support spacings. Where the tray will carry heavy power cables or require longer unsupported spans, 6061-T6 with a minimum yield strength of roughly 240 MPa is the better choice. Any tray supplied for a PV project should carry a mill certificate confirming the alloy and temper.

Surface finish options

The alloy grade matters, but the finish determines how the tray behaves in a specific micro-climate. A bare mill finish is acceptable in indoor and arid installations. Coastal sites, high-humidity regions, and dusty industrial areas require an anodized, powder-coated, or PVDF-coated surface.

The complete aluminum alloy cable tray system from Jiangsu Youming Group Co., Ltd. covers ladder, trough, and punched tray profiles in multiple finishes, so a single procurement package can serve both the DC string cable and the communications cable route.

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The table below summarizes the finish options that should be evaluated for a solar project.

Sizing and Load Calculation for Solar Cable Runs

Size a solar cable tray by cable fill, not by tray width alone: per NEC 392.22(B), the sum of cable cross-section areas must not exceed 50 percent of tray cross-sectional area, and every tray must withstand the installed cable load plus a 200 lb concentrated live load as defined in NEMA VE 1.

In practice, this means a 300 mm ladder tray carries about 32 to 42 DC cables sized 4 sq mm, depending on cable dressing and on the allowance for future circuits. Support spacing follows the load class, not the tray width. On a 1.5 m span, an aluminum ladder tray in load class C handles a uniform load of 150 kg per meter; increasing the span to 3.0 m can reduce the allowable load to around 40 kg per meter.

Structural weight is part of the load. The chart below compares the dead weight of a 300 mm ladder tray in the three materials most commonly quoted for solar projects.

Installation Best Practices for PV Projects

Install aluminum cable trays in the sequence of support bracket mounting, tray assembly, expansion control, and cable dressing, and apply solar-specific rules for bend radius, UV exposure at tray entry points, and system bonding.

• Fix supports at calculated spacing

  Mount brackets at 1.5 to 2.0 m spacing on the PV structure. Use slotted adjustment plates so the tray line can be aligned after the structure tolerances have settled.

• Assemble sections and splice plates

  Connect tray sections with galvanized or stainless splice plates and torque fasteners to the manufacturer specification. Do not over-torque aluminum, which is softer than steel.

• Install expansion couplers on long runs

  Place expansion couplers at intervals of 20 to 25 m in unbroken tray runs to absorb thermal movement without buckling the splice plates.

• Dress cables and control bend radius

  Lay DC cables with a minimum bend radius of 5 times the cable outer diameter at every exit from the tray and at every combiner box entry.

• Bond and ground the complete system

  Bond the continuous tray system and connect it to the PV plant grounding network using listed clamps rated for aluminum-to-copper connections.

Matching Cable Trays to Photovoltaic Mounting Systems

Solar cable trays perform correctly only when the tray support brackets are designed together with the PV mounting structure, because ground-mount and tracker frames are motion-critical systems that cannot accept rigid tray attachments.

Ground-mounted arrays

For fixed-tilt ground systems, tray brackets are usually clamped to the purlin or rail. The ground solar mounting structure determines the bracket height, so the tray layout should be confirmed before the steel is fabricated. For tracker systems, a service loop or flexible transition is required between the moving torque tube and the fixed cable path.

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Roof-mounted arrays

Roof projects benefit from aluminum trays because the low dead weight keeps additional roof loading to a minimum. Pair the trays with the photovoltaic mounting brackets from the same supplier so that bolt patterns and corrosion protection are consistent across the roof system.

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Sourcing from a Full-Line Manufacturer

Jiangsu Youming Group Co., Ltd. has been producing cable tray systems since 2015 from its plant in Dongtai, Jiangsu Province. The company profile page documents a workshop area of more than 26,000 sq m and an annual cable tray capacity exceeding 30,000 tons. Its fully automated production lines handle coil slitting, roll forming, welding, riveting, laser cutting, and CNC turret punching, which means a 50 MW project can be quoted as one complete supply package rather than as a collection of parts.

Buyers who work with Youming also get engineering and testing capability for load calculations, custom profiles, and finish selection, which closes the gap between a tray drawing and a tray that installs without field rework.

Frequently Asked Questions