Siemens BH17 7ER Installation Manual page 48

L D H
OOP ETECTOR ANDBOOK
The installation manuals for all street furniture including cabinets, poles,
signals, detectors, key switches and push buttons should be amended where
necessary to include this information.
Spacing of Cables from LRT Track
Vehicle detector loops and feeder cables may have to be laid under LRT
tracks to detect the passage of light rail vehicles.
The insulation of the cables should be adequate to withstand the maximum
touch voltage and the installation procedure should ensure adequate
separation to prevent chafing due to track movements.
Avoiding Accidental Contact with Tools and Test Equipment
It is common practice to connect power tools and test equipment to the
controller maintenance socket. The case of the tools or test equipment will
therefore be connected to the controller earth and should not come into
contact with the LRT track or vehicles.
Neither the RCD if fitted nor the mains supply fuse will provide protection
against the possible heavy current resulting from accidental contact.
Care must be taken when using metal ladders to gain access to above ground
detectors and signals heads to prevent making contact between the street
furniture and LRT track or vehicles. Installation and maintenance manuals
should be amended where necessary to include this information.
Isolation of Interface between LRT and Traffic Control Equipment
The design of the interface between remote LRT outstations and traffic control
equipment should be isolated so that it is not affected by different earth
potentials at the two sites. The isolation should apply to the signals
conductors and any cable armour or screen, so that earth leakage current
cannot flow between the cabinets.
667/HE/20663/000 Issue 13 Page 48