Which Test Should Cable Trays Go Through? How to Detect It？
When the whole project is completed, and the cable tray is already delivered, if there is a problem with the product itself, it may lead to corrosion situation in just a few years or even a few months, thus the property loss caused by the replacement is much higher than the product itself.
Why do we need to conduct strict testing on cable trays?
When the whole project is completed, and the cable tray is already delivered, if there is a problem with the product itself, it may lead to corrosion situation in just a few years or even a few months, thus the property loss caused by the replacement is much higher than the product itself. AndIf the load-bearing performance is not up to standard, it will also cause plastic deformation or even serious collapse. The collapse will not only cause property damage but may also cause short circuit and electrical fire. If there is no strict testing and required standards, it is impossible to avoid the excessively harmful chemical elements contained in the cable tray, which will directly endanger human health and destroy ecological safety.
Therefore, we need to strictly follow thetesting specified in the testing standards to guide production process. Only in this way can we truly ensure the safety of cable routing.
What tests should cable trays go through? How to detect it?
01 Load-bearing test
The bearing capacity is the most basic testing item to identify the quality of the cable tray. The load-bearing test is also called the SWL (safe working load) test, which is to test the bearing capacity of the cable tray according to the standards of the International Electrotechnical Association.
The test shows that qualified cable trays need to pass the relative deflection, which means it should not be greater than 1/200 when it bears the rated uniform load. But the values of different heights and different widths of cable trays are obviously different. In standard testing, the cable tray that occupies 1.5 meters space is generally used as the testing sample.
Take the cable tray frame of 100mm (height)-300mm(width)-3000mm (length)-5.0mm (wire diameter) as an example, the safe bearing capacity of the cable tray meter could reach to 141 kg, at the same time, it would keep the solder joints completed, rather than being de-soldered, avoiding collapsing, and the relative deflection should also be less than 1/200 within 24 hours.
02 Pulling test
The single-point tensile test of the cable tray is the key to ensuring that the strength of the whole product meets the requirements, and it is also a test of the strength of the solder joints for the cable tray. The tensile test uses a tensile instrument to test the tensile strength of solder joints. Taking the cable tray frame of 100mm (height)-300mm (width)-3000mm (length)-5.0mm (wire diameter) as an example, under the conditions of 23±2°C, 50±5% RH, and hydraulic press speed of 5mm per minute, the minimum damage is greater than 1KN, the cable tray is not de-soldered, then it is determined as passed.
03 Salt spray test
The salt spray test uses accelerated corrosion method to assess the ability of products to resist corrosion damage. The commonly used is a 5% sodium chloride solution, which sprays salt water into a fine mist, and then places the sample in the salt spray environment for corrosion resistance testing.
So, what is the standard for different cable trays to pass the salt spray test?
The following is the standards for different type of cable trays:
Salt spray time of electrogalvanized cable tray ≥ 96 hours;
Salt spray time of hot-dip galvanized cable tray ≥ 720 hours;
Salt spray time powder-coated cable tray ≥ 480 hours.
04 Coating Thickness Test
A coating thickness test is a test to detect the thickness of metal and oxide coatings on the surface of materials. It is more common to use a film thickness gauge to detect.
The measurement range of the film thickness meter is 0-1250μm, and its measurement accuracy is ±(1%-3%)+1.5μm.
So what is the galvanized standard for a qualified cable tray?
Galvanized zinc layer thickness ≥ 12μm
Hot-dip galvanized zinc layer thickness ≥ 60μm
Powder coating zinc layer thickness≥ 60μm
05 Environmental testing (RoHS)
RoHS is a mandatory standard established by EU legislation, its full name is "Restriction of Hazardous Substances Directive 2002/95/EC." RoHS stands for Restriction of Hazardous Substances and impacts the entire electronics industry and many electrical products as well. The original RoHS, also known as Directive 2002/95/EC, originated in the European Union in 2002 and restricts the use of six hazardous materials found in electrical and electronic products. All applicable products in the EU market since July 1, 2006, must pass RoHS compliance.
EU RoHS specifies maximum levels for the following 10 restricted substances. The first six applied to the original RoHS while the last four were added under RoHS 3, which took effect on July 22, 2019.
Cadmium (Cd): < 100 ppm
Lead (Pb): < 1000 ppm
Mercury (Hg): < 1000 ppm
Hexavalent Chromium: (Cr VI) < 1000 ppm
Polybrominated Biphenyls (PBB): < 1000 ppm
Polybrominated Diphenyl Ethers (PBDE): < 1000 ppm
Bis(2-Ethylhexyl) phthalate (DEHP): < 1000 ppm
Benzyl butyl phthalate (BBP): < 1000 ppm
Dibutyl phthalate (DBP): < 1000 ppm
Diisobutyl phthalate (DIBP): < 1000 ppm
06 Fire test (E90)
Fire test according to DIN 4102-12-1998 "Fire Performance of Building Materials and Components", Part 12: Fire performance of cable systems to maintain circuit integrity, the fire performance of cable trays is required and tested.
The cable tray is placed at a high temperature of 1000 degrees, and it is placed under loading situation for 90 minutes, the bridge does not collapse.
A good cable tray should adapt to various load and span conditions required by its wiring engineering, meet its mechanical performance requirements, and have a reasonable structure, which can effectively protect cables from corrosion, and fire.