architecture big building conduit electronics exhaust factory hydraulic line industrial industry iron large line metal metallic pipe pipeline pipework piping shining silver technology tube tubes tubing angles arm danger dangerous electricity elevated elevation equipment external height heights high hydraulics lifting machinery on-high perspectives power power-lines power-pole raised raising repair-crew replace replacement replacing risks risky safety service trucks up-high vehicles work workman workmen basket cherry-picker connecting connections Harness insulators raised-platform safety-harness