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ISO IEC TS 29125:2017 pdf free

Cabling may be installed in different types of continuous and non-continuous pathway systems as described in ISO/IEC 14763-2. The installation of a cable within the pathway systems should take into account the specified operating temperature of the cable. Due to the Joule effect, each energized conductor has a temperature rise. Larger cable bundles have more heat generation and therefore the temperature rise is worse than smaller cable bundles.
The cable bundle size is limited by the current capacity in 6.3 and the induced temperature rise that results in an operating temperature of the cable, not to exceed its temperature rating.
The following guidelines for pathway selection and installation should be considered:
a) installation design including the type of pathways selected, the pathway fill factor, whether the pathway is sealed at both ends,
b) the pathway environment and whether the pathway goes through thermally insulated areas, in which case the type of insulation will be a significant factor. For optimal thermal performance, pathway design should avoid any insulated areas,
c) thermal aspects of the entire pathway (e.g. open tray, closed tray, ventilated, non-ventilated, plastic conduit, metal conduit, fire barriers) should be taken into account.
Different segments of a link can have different ambient temperatures, which can influence the amount of remote power that can be delivered. Therefore the ambient temperature in different length segments of a link or channel has a direct impact on the operating temperature of the cable used for the link or channel and can limit the capability of the cable for remote power delivery to powered terminal equipment. The worst case installed cabling condition with respect to the maximum ambient temperature shall be used to determine the maximum operating temperature for a link or channel when subject to remote powering.
When remote power is applied to balanced cabling, the temperature of the cabling will rise due to resistive heat generation (Joule effect) in the conductors. Depending on cable construction and installed cabling conditions, the heat generated will be dissipated into the surrounding environment until a steady state is reached with the temperature of the cable bundle (operating temperature) higher than the ambient temperature of the surrounding environment.The maximum temperature of any cable shall not exceed the temperature rating of the cable. The standards in the ISO/IEC 11801 series require this temperature to be 60 °C (minimum).ISO IEC TS 29125 pdf download.

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