Hi All,
This is regarding Street lighting cable installation which follows the BS standard 7671, In one of my project contractor has installed16Sqmm cable from first lighting column to the last lighting column. However, due to the impedance/earth fault, the cable size needs to increase from 16sqmm to 25sqmm (feeder pillar to the last lighting column) to get a compliant electrical calculation.
To avoid significant work in the ground, the contractor would like to install bigger size cable(25sqmm) from feeder pillar to the first lighting column and retain the small size (16sqmm) cable from first lighting column to the last lighting column in the ground.
Based on BS7671, could anyone let me know that using the bigger size cable from the FP to the first column and drop in cable size from the first column to the last column is acceptable?
Reagrds
Sinu123
