When selecting FRP cable trays, the primary focus is corrosion resistance, which is the core guarantee for their suitability in harsh environments. Prioritize requesting that the supplier provide an authoritative test report confirming that after 1000 hours of immersion in the media they will encounter (such as 5% hydrochloric acid, 10% sodium hydroxide, seawater, etc.), the weight change is ≤±1% and the strength retention is ≥80%. This prevents resin shedding and structural brittleness after long-term use due to a mismatch between the material and the media. For outdoor use, UV resistance should also be verified. The product must contain an anti-UV additive, exhibit no cracking or discoloration after xenon lamp aging testing, and have a flexural strength retention rate of ≥75% to prevent brittleness after high-temperature exposure.
Mechanical performance directly determines whether the cable tray can safely bear the weight of cables and external forces during installation, and must strictly comply with the GB/T 21238-2017 "Glass Fiber Reinforced Plastic Cable Tray" standard. A flexural strength of ≥120 MPa is crucial, ensuring that the cable tray does not significantly bend or break when laying multiple heavy cables (such as low-voltage power cables), especially in long-span installations (>6 meters). Impact strength (simple beam method) must be ≥15 kJ/m² to withstand minor everyday impacts (such as equipment handling collisions and dropped tools), preventing the fiberglass from cracking due to its lack of toughness. A tensile strength of ≥80 MPa prevents the cable tray from breaking due to uneven stress during hanging and hoisting, making it particularly suitable for vertical installations or high-altitude installations.
Insulation performance is a core advantage of fiberglass cable trays over metal ones, and specific indicators are required to ensure safe use. The volume resistivity must be ≥10¹⁴Ω・cm at room temperature. This ensures that the cable tray itself is non-conductive, eliminating the need for mandatory grounding, as is required for metal cable trays. This effectively reduces the risk of leakage caused by poor grounding and makes it particularly suitable for environments with strong electric fields, such as substations and high-voltage equipment rooms. Furthermore, voltage withstand performance must be verified, requiring a 1.5kV AC voltage withstand for 1 minute without breakdown or flashover. This verifies the cable tyay's insulation stability under transient high voltages, preventing short circuits caused by insulation failure and ensuring the normal operation of the electrical system.
The combustion performance rating must be selected based on the project's fire protection requirements to avoid further fire spread in the event of a fire. In ordinary civilian buildings (such as office buildings and residential buildings), cable trays must meet Class V-2 in accordance with GB/T 2408-2021, "Plastics - Determination of Combustion Behavior." This means that in a vertical burning test, the flame extinguishes within 30 seconds, and dripping does not ignite the absorbent cotton underneath. High-risk locations, such as fire control rooms, equipment rooms, and underground garages, require an upgrade to Class V-1 (dripping does not ignite the absorbent cotton, and the flame extinguishing time is even shorter) or Class HB (burning velocity ≤ 76 mm/min in a horizontal burning test). Some projects with extremely stringent fire protection requirements also require Class B1 flame retardancy. In these cases, additional smoke density and toxicity testing is required to minimize the release of harmful gases in the event of a fire, allowing for evacuation.
Dimensional stability prevents cable tray deformation due to temperature fluctuations or long-term loads. First, pay attention to the coefficient of thermal expansion, which is generally required to be between 1.5×10⁻⁵/°C and 2.5×10⁻⁵/°C. If the coefficient is too high, the large temperature difference between day and night can easily cause cracking at the cable tray joints when laying cables outdoors over long distances (such as >50 meters). Therefore, it is necessary to reserve reasonable expansion joints (generally 10-20mm every 10-15 meters). Secondly, the heat deformation temperature should be selected according to the ambient temperature. For ordinary indoor temperature scenarios, it should be ≥80°C. For high-temperature scenarios near boilers and ovens, products with a heat deformation temperature of ≥120°C (usually epoxy resin or phenolic resin base materials) should be selected to prevent the cable tray from softening and sagging at high temperatures, which would affect the stability and structural safety of the cable laying.
