![]() I made the calculations and have some questions. the sheets you sent helped me a lot in understanding the calculations. RE: Underground cables in Concrete Encased PVC ducts Adam1980 (Electrical) If the 3 cables in one duct of the upper row –first or last will be loaded with 175 A the ampacity of the rest of cables will drop to 161.5 A. The first way result was 166 A and the second-considering also equally loaded cables-163.5 A. There are slight differences between results. This way is difficult to transfer in Excel. This is not a relation but a procedure in order to find the final temperature distribution and iterate the way until reach the maximum permissible. If we intend to load differently one or more cables then we have to follow ch.2.2.3.1 Unequally loaded cables. This way uses global formulae simplifying the calculation. We calculated the ampacity for 27 single core cables equally loaded following IEC 6 ch.2.2.7.3 External thermal resistance of the duct (or pipe) T4”’ connected with 2.2.3.2 Equally loaded identical cables. RE: Underground cables in Concrete Encased PVC ducts 7anoter4 (Electrical) 26 Oct 13 09:21 in PVC duct) to see what is the ampacity and compare with the one given by the manufacturer for laid direclty in ground.įinally, you said that you are using information from ABB for the 9 cables arrangement but is it valid to use the factors from IEC 502 when considering 3 x 3 configurations, the factors are for horizontal arrangement only! correct? ![]() I am doing calcualtions only for one cable (3x1 300 mm.sq. ![]() I believe i have all data i need to calculate the ampacity using the equations in 287-1-1 and 287-2-1 but i am not getting a logical result. for a rough estimation is this valid?įor the duct in question it is a 3 x 3 configuration vertically and horizontally there is 50 mm spacing between the ducts (165 mm center to center)and 75 mm from the concrete encasing border to the duct order also vertically and horizontally. Please contact us for more information.So if the rating for cable in ducts is 166 A and for directly buried is 184 A the factor in between is around 0,9 (assuming all other conditions are the same). With Cal Am Duct Spacers, contractors can save installation time and reduce costs while ensuring the accurate separation of ducts.Īvailable in pre-assembled configurations. In addition, the spacers are environmentally friendly, made from recycled materials, and recyclable. Their lightweight design makes them easy to handle and transport. The ease of assembly and resistance to soil conditions and extreme temperatures make Cal Am Duct Spacers a trusted choice for contractors. Overall, Cal Am Duct Spacers are a reliable and cost-effective solution for any duct placement project. Offering an extensive range of sizing means Cal Am spacers can be tailor-fit to any project-big or small. These sturdy, versatile spacers will not shift under the weight of your workmen and stay firmly in place during fill.Īvailable in eighteen (18) sizes, Cal Am Duct Spacers accommodate ducts ranging in size from 2.00” – 8.00” | 50mm – 200mm while providing duct separation of 1.50” – 3.00” | 40mm – 80mm. They utilize a proven two-piece design precisely engineered to support duct arrays within trenching before encasement. Vertical and horizontal interlocking duct spacers for fast secure field assemblyĬal Am Duct Spacers have been the choice for contractors for decades.
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