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Communications CMP Cable Installed Outdoors

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    Communications CMP Cable Installed Outdoors

    We have a 6c-16AWG, CMP, CL2R, FEP/FEP, 300V, cUL, cable installed outdoors in covered ladder type instrumentation cable tray and is routed through conduit on tray take off to terminations. The weather is around +35 deg c to -40 deg c worst case.

    1. Can we install CMP cables in cable trays? I read some white papers from manufacturers that says it can be. CEC 2018 Table 19 also allows it (in “raceways” with no exceptions to cable tray)

    2. On outdoor environment at freezing temperatures, will it matter if it is in covered cable tray or conduit, as in both cases, cable will still be subjected to below rated operating temperature? covered trays also offer mechanical protection but do not mitigate the freezing temperature. UL standardized the minimum operating temperature for this cable as -20 deg C (unless otherwise marked on the cable). One may argue that if they it is in conduit, the cable will not be subjected to breaks even at temperatures lower than -20 Deg C. However, I would see that the cable may break by itself without any impact due to -40 Dec C.

    I would like to obtain some advise, as this falls in the cracks but I can be wrong.
    Last edited by FieldGuy; 10-16-19, 08:07 AM.

    #2
    The one time I used CMP outdoors, (because that's all I had on the truck) after a few years the jacket broke all over and let water migrate through it which in turn degraded the conductor insulation making the cable fault. Besides not being cold temperature tolerant, it's not UV resistant at all. Granted, this was not in conduit or an enclosed cable tray but I would never do it again.

    -Hal

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