IEC 60364-5-52 (2009), Table B.52.20 shows the derating factors for maximum 9 numbers of cables per tray or ladder. Does this mean that maximum allowable cables in single cable tray can not exceed 9 ?
Is there any other IEC standard that provides the group derating factors for more than 9 LV cables run in single cable tray ? Thanks.
I don't think the intention is to limit to 9 cables. For 9 or more cables I think the intention is that you use the derating for 9 - i.e. this would be the maximum worse case factor to apply.