Cable ladders PTR type, even though they are suitable for the containment of each type of cable, are particularly suitable when a high capacity load is required together with an extremely low deflection. Constructional features, which are the results of SITIE long experience in the field of industrial installations, permit their use and installation in all kinds of environment where reliability and safety are priority-requirements. Further to a long experience under a quality control system, with the ISO 9001-2008, ISO 14001 and OHSAS 18001 certifications for quality, environment and safety, SITIE has obtained the IMQ mark for this kind of cable trays. Certified typologies are countermarked on this catalogue with mark
Cable ladders PTR type are designed and manufactured in accordance with the standard CEI EN 61537 Class 23-76 and can be manufactured with the following materials:
• Carbon steel S235JR (reference standard UNI EN 10025) hot dip galvanized after working according to CEI 7.6;
• Stainless steel AISI 304;
• Stainless steel AISI 316.
Side-rails and rungs are obtained by cold-profiling of coils. Welding is executed by MAG process on a automated system, which gives to the structure the maximum rigidity. The standard distance between centre-lines of rungs is 300mm; on request, we can supply ladders with a different distance between centre-lines. Bending radii of special pieces take into consideration the CEI 11-17 standard, which settles the minimum bending radius according to cable's diameter; on request, we can supply different bending radii. Standard covers are plane type and 1.00mm thick. On request, higher thickness can be manufactured as well as flowing type covers.
Cable ladders capacity load
Cable ladders PTR type have been tested through strict tests, to define the maximum admissible load (SWL - Safe Working Load) in compliance with the CEI EN 61537 standard. View our catalog to find the diagrams which define, according to the distance between supports, the maximum admissible distributed load (UDL - Uniformly Distributed Load) and the maximum admissible load considering an additional concentrated load (CL - Concentrated Load). As concentrated load we consider a load of 900 N added in the middle span with respect to the supports. The CEI EN 61537 standard states that the maximum acceptable longitudinal inflexion is 1/100 of the distance between supports, and that the maximum acceptable transversal one is 1/20 of tray width.
Cable ladders PTR type have been tested to verify the electrical continuity in accordance with CEI EN 61537 standard. The test consists in the passage all along the elements of a 25A electric current, with a frequency between 50 and 60 Hz; the voltage drop must be measured both through the joint and on the whole tray, therefore:
• between two points, 50mm away from each side of the joint;
• between two points, on one side 500mm away from the joint. The measured impedances shouldn't exceed 50 mΩ through the joint and 5mΩ per metre without the joint. The test has been carried out on two straight elements connected by one joint fixed by 8 cup square screws M6x15.